Virus World

A study found that the floor and walls around the toilet could still get contaminated with viruses from the toilet bowl even when the lid is down during flushing. Will shutting the toilet lid when you flush really keep nasty microbes from leaving the bowl and spraying all over the place? Well, it’s not exactly an open and shut case, according to a new study published in the American Journal of Infection Control. The study found that the floor and walls around the toilet could still go quite viral, so to speak, even when the lid stays down during the flush. Yes, even the walls around the toilet ended up getting contaminated with viruses from the toilet bowl. For the study, a team of researchers from the University of Arizona (Madison P. Goforth, BS Stephanie A. Boone, PhD Justin Clark, MS Priscilla B. Valenzuela, MS, FRSPH, and Charles P. Gerba, PhD) and Reckitt Benckiser, LLC, the makers of Lysol (Julie McKinney, PhD, and M. Khalid Ijaz, DVM, PhD) dumped some bacteriophage MS2 into two different types of toilets...

Experts have long understood that a new polio vaccine developed to try to minimize the risks associated with the oral polio vaccine made by Albert Sabin might also cause the problem it was created to sidestep. It’s now clear that theoretical risk is a real one. The Global Polio Eradication Initiative announced Thursday that six children in the Democratic Republic of the Congo and one in Burundi have been paralyzed by viruses from the new vaccine, which is referred to as novel oral polio vaccine, or nOPV2. (The “2” signals the vaccine targets type 2 polioviruses.) In addition, five environmental samples collected from Burundi contained the so-called type 2 circulating vaccine-derived polioviruses, or cVDPV2s. “We are disappointed,” said Ananda Bandyopadhyay, deputy director for technology, research, and analytics on the polio team of the Bill and Melinda Gates Foundation, a partner in the polio eradication effort. “Any such outbreak is disappointing.” The Gates Foundation is one of a half-dozen partners in the Global Polio Eradication Initiative. The others include the World Health Organization; UNICEF, the United Nations Children’s Fund; the Centers for Disease Control and Prevention; Gavi, the vaccine alliance; and the service club Rotary International.

Bandyopadhyay and the polio eradication initiative itself were quick to point out that this turn of events was not unexpected. The live polioviruses used in oral vaccines are manipulated to eliminate their ability to paralyze. Children who receive these vaccines shed live viruses in their stools. In settings where sanitation and hygiene are poor, the viruses can move from child to child, effectively indirectly vaccinating children whom vaccination teams haven’t reached — a feature that has made the Sabin vaccines the workhorse of polio eradication. But if the viruses spread long enough, they can regain the ability to paralyze — a problem that led the polio program to stop using type 2 oral vaccine in 2016, in a bold and ultimately failed effort, known as “the switch,” to stop spread of type 2 viruses from the Sabin vaccines. The injectable polio vaccine, designed by Jonas Salk and used in affluent countries like the United States, does not contain live viruses and therefore doesn’t trigger paralysis. But while it prevents paralysis, it cannot stop transmission of polioviruses — wild type or vaccine derived — which makes it less useful in countries where vaccine-derived viruses are spreading. In recent years, the nearly 35-year-old effort to rid the world of polio has managed to drive numbers of infections with wild viruses down to low levels. Last year, only three countries — Pakistan, Afghanistan, and Mozambique — reported 30 cases. So far this year, there has been only one case detected, in a child in Afghanistan. But as the battle against wild viruses has gained ground, use of the oral vaccine has seeded chains of transmission of the vaccine-derived viruses. In 2022, nearly 800 children or young adults in roughly two dozen countries developed paralytic polio after being infected with one of the vaccine viruses from the Sabin vaccines. Among them was an unvaccinated young man in New York State, this country’s first polio case in nearly a decade.

Of the three original strains of polio — types 2 and 3 have been eradicated, only type 1 remains — the portion of the Sabin vaccines targeting type 2 viruses triggers the vast majority of vaccine-derived polio cases. A few years ago, with support from the Gates Foundation, the novel oral vaccine targeting type 2 viruses was developed. It was put into use in mid-March of 2021 — two years ago. Since then 590 million doses of nOPV2 have been administered in 28 countries. The seven cases of paralytic polio, which stem from two chains of vaccine-derived viruses, are far fewer than would likely have occurred if those hundreds of millions of doses had been the Sabin vaccine, Bandyopadhyay said. An analysis from the Gates Foundation’s polio team suggested that there would have been 30 to 40 new chains of type 2 vaccine viruses over that period, rather than two, he said. Other experts agreed it is important to put the finding in context. “I’m not alarmed. It’s a much better tool than we used to have,” said Walter Orenstein, a polio expert at Emory University. “It’s not perfect,” he said of the new oral vaccine. “But given its rarity, it hopefully will be able to do the job. At least not generate lots of these kinds of outbreaks.” Kim Thompson, president of the nonprofit organization Kid Risk and a mathematical modeler who has worked on polio eradication for decades, said this event is only showing the world that what was assumed about the new oral vaccine is in fact true. “This possibility has always been out there in the cards. And really this is just the proof of concept that the nOPV2 can lose the attenuated mutations and behave like other live polioviruses, and particularly do so in populations where [vaccine] coverage is low,” she said. But Thompson is worried that given the low levels of immunity to type 2 polio, even less frequent outbreaks of vaccine-derived viruses will amplify a problem the polio program is struggling to contain. “The reality is that since we have transmission happening in these areas with low coverage and this immunity gap that exists … there’s more room for these viruses to go. That’s part of the challenge here, is to figure out what to do to stop type 2,” she said.

Helen Branswell

Senior Writer, Infectious Diseases

Helen Branswell covers issues broadly related to infectious diseases, including outbreaks, preparedness, research, and vaccine development. Follow her on Mastodon and Post News.

New York Gov. Kathy Hochul (D) on Friday declared a state of emergency after poliovirus was detected in the sewage of a fourth county in the state in an effort to boost vaccination rates as some regions lag well behind national vaccination levels.

KEY FACTS

This report describes a case of polio in an unvaccinated adult resident of New York and highlights why it’s important to stay up to date on recommended poliovirus vaccination. 

The following essay is reprinted with permission fromThe Conversation, an online publication covering the latest research. The first case of polio in the U.S. since 2013 was announced by New York state health officials on July 21, 2022. The U.S. resident had not been vaccinated. Polio was a common cause of paralysis in children before safe and effective vaccines were invented in the mid-20th century. Thanks to global vaccination campaigns, polio is now almost eradicated, with only 13 cases of endemic wild poliovirus reported in 2022 to date worldwide.  The New York patient reportedly contracted a form of polio that can be traced back to the live, but weakened, poliovirus used in the oral polio vaccine. This version of the vaccine has not been used in the U.S. since 2000. Health officials said the virus affecting the male patient, who has muscle weakness and paralysis, likely originated somewhere overseas, where oral vaccines are still administered. William Petri is an infectious disease specialist and chair of the World Health Organization’s Polio Research Committee. Here he explains what vaccine-derived poliovirus is and why the inactivated polio vaccine administered in the U.S. today can’t cause it. 

What are the two kinds of polio vaccine?

Vaccines introduce a harmless version of a pathogen to your body. The idea is that they train your immune system to fight off the real germ if you ever encounter it. The oral polio vaccine, originally developed by Albert Sabin, uses a live but weakened poliovirus that one swallows in a sugar cube or droplet. Scientists weaken – or attenuate – the virus so it can no longer cause disease.  The other kind of polio vaccine was originally developed by Jonas Salk. It contains inactivated, dead virus. It is administered by an injection. In the U.S., children receive the inactivated polio vaccine at 2, 4 and 6 months of age. It provides nearly complete protection from paralytic polio.

How can the live vaccine lead to a case of polio?

The weakened form of the live virus in the oral vaccine cannot cause disease. However, because the vaccine is given orally, the weakened virus is excreted in the feces and can spread from someone who is vaccinated to their close contacts. If the weakened virus circulates person to person for long enough, it can mutate and regain its ability to cause paralysis. The mutated virus can then infect people in communities with poor sanitation and low vaccination rates, causing disease and even paralysis.  This is an exceedingly rare occurrence. With more than 10 billion doses of the oral polio vaccine administered since 2000, there have been fewer than 800 cases of vaccine-derived polio reported. Apparently, the current patient in New York was somehow exposed to a mutated poliovirus that had been transmitted after vaccination overseas. Earlier this summer, routine surveillance spotted vaccine-derived poliovirus in London’s sewage system, but no cases have been reported there.

Why use the oral vaccine anywhere if it comes with this risk?

There’s a positive aspect to the fact that the weakened live virus can circulate in the community once oral vaccine recipients shed it in their feces. Traveling a feces-to-oral route, it can help induce immunity even in people who weren’t directly vaccinated. The oral polio vaccine is also cheaper and easier to administer than inactivated polio vaccines. Most importantly, the live-virus vaccine stops transmission of wild poliovirus in a way that the inactivated-virus vaccine does not. The eradication of polio in the Americas, Europe and Africa has been accomplished solely through the use of the live oral vaccine. Once polio has been wiped from a continent, then it is safe to stop using the oral live vaccine and use only the inactivated vaccine, which does prevent disease in recipients and does not pose the rare risk of vaccine-derived paralytic polio.  A new and safer oral polio vaccine that has been engineered not to mutate is now replacing the earlier live-virus vaccine. Thus, even this extremely rare complication of polio vaccination should soon become a thing of the past. 

How close is the world to eradicating polio?

Thanks to tremendous global effort, two of the three viruses that cause polio have been eradicated. The world is now on the verge of eradicating the final one, wild poliovirus 1 (WPV1). Today endemic polio is found only in Pakistan, with 12 cases of paralytic polio so far in 2022, and Afghanistan, with just one case this year. Africa has two cases, imported from overseas, which are being contained by additional vaccination campaigns. Once wild poliovirus has been eradicated from the planet, vaccination efforts may be able to switch to the inactivated polio vaccine, eliminating the risk of any future vaccine-derived cases.

This article was originally published on The Conversation. Read the original article.

New York State reported Thursday that it has detected a case of vaccine-derived polio in a person in Rockland County, north of New York City, the first such recorded case in the United States since 2013.  The unidentified individual developed paralysis, said Beth Cefalu, Rockland County’s director of strategic communications. Polio paralysis is irreversible. The area where the case was detected was the epicenter of a large measles outbreak in 2018-2019 that was fueled by low vaccination rates among communities of Hasidic Jews. The outbreak went on for so long that the country almost lost its measles-free status. The memory of that episode is provoking concern that the area might be ripe for additional vaccine-derived polio cases to occur. “I think it’s concerning because … it can spread,” said Walter Orenstein, a polio expert at Emory University. “If there are unvaccinated communities, it can cause a polio outbreak.” “The inactivated polio vaccine we have is very effective and very safe and could have prevented this,” he said. “We need to restore our confidence in vaccines.” The Centers for Disease Control and Prevention said in a statement that while the risk is low for people who are vaccinated, there is risk for those who have not had the recommended three doses of injectable polio vaccine. “Most of the U.S. population has protection against polio because they were vaccinated during childhood, but in some communities with low vaccine coverage, there are unvaccinated people at risk,” the statement said. “Polio and its neurologic effects cannot be cured, but can be prevented through vaccination.” 

The New York State department of health said in a statement that the person was infected with a type 2 vaccine-derived poliovirus, which would have come from oral polio vaccine used in a number of countries, but not the United States. The U.S. stopped using oral polio vaccine in 2000. Cefalu told STAT the case is still being investigated, but it is believed the individual had not recently traveled outside the country to a place where type 2 vaccine-derived polio viruses are spreading. If that is the case, that would indicate someone else inadvertently imported the virus, suggesting there may be additional undetected transmission. Only a small portion of people infected with polioviruses will go on to be paralyzed.  Kimberly Thompson, a polio expert who is president of the nonprofit organization Kid Risk, said it’s not a surprise to see a vaccine-derived case pop up in this country, noting public health authorities in the United Kingdom recently discovered vaccine-derived polioviruses  in sewage in London, indicating some transmission there.  “With Covid having disrupted immunization (even in the U.S.) and travel now having resumed and much more type 2 poliovirus transmission happening … it’s been only a matter of time before we’d have some detection of polioviruses in sewage, as happened recently in the U.K, or more tragically, a case,” Thompson told STAT in an email. “There’s just a lot more polio going around than there should be.” The oral vaccine contains live but weakened polioviruses, which immunized children excrete in their stools. In places where hygiene is poor, these viruses can spread from child to child, immunizing others as they do. But as they spread, the vaccine viruses can regain the power to paralyze. Such cases are called vaccine-derived polio.  The United States uses injectable polio vaccine that contains killed viruses to teach the immune system to recognize and fight off polio. It cannot cause paralysis.

Mary Bassett, New York State’s health commissioner, said people who are vaccinated against polio do not face a risk from the newly discovered case. But children who are not immunized against the virus should receive the vaccine. “Based on what we know about this case, and polio in general, the Department of Health strongly recommends that unvaccinated individuals get vaccinated or boosted with the FDA-approved IPV polio vaccine as soon as possible,” Bassett said. Rockland County will host vaccine clinics on Friday and Monday, the department’s statement said. The United States used to have upwards of 20,000 paralytic polio cases a year in the early and mid-1950s, Orenstein said, recalling that as a 7-year-old in 1955 he was reluctant to be vaccinated when the Salk polio vaccine — the injected form — was released. “My mother said to me: ‘Better you should cry than I should cry,’’’ he said. With the advent of effective polio vaccines, the disease retreated in much of the developed world. The last recorded case of domestically acquired wild polio was in 1979, though there was an imported case in 1993. But over the years there have been rare imported cases of vaccine-derived polio, from countries where the oral vaccine is still in use. Orenstein said detecting where the virus in the New York case came from is critical. That work can be done by comparing the genetic sequence of the individual’s virus with others in a database the polio eradication program maintains. The world has been trying to eradicate polio for decades, with two of the original three types of polio — types 2 and 3 — having been driven out of existence. But the remaining version, type 1, has defied efforts to end its spread to date. Wild-type polio cases are at low numbers; the viruses are only endemic at this point in Afghanistan and Pakistan, which have recorded a total of 12 cases this year. But recently it was discovered that viruses from Pakistan had made their way to Malawi and Mozambique, a highly unwelcome development. Meanwhile, the numbers of vaccine-derived cases have exploded in Africa and some other parts of the world after the failure of an effort in 2016 to take type 2 viruses out of the oral vaccine. It was felt that given the fact that wild type 2 viruses no longer existed, it was not ethical to use oral vaccine containing type 2 viruses, because of the risk they would regain the power to paralyze.

In a coordinated move called “the switch,” countries around the world were told to stop using trivalent oral vaccine — vaccine that contained all three types of polioviruses — and begin to use a bivalent form that did not include type 2. In the years since, chains of transmission of type 2 vaccine-derived virus have spread to more than 40 countries around the world and the polio eradication program has struggled to contain the spread. So far this year 167 children in 12 countries have been paralyzed by type 2 vaccine viruses, not including the individual in New York. The Global Polio Eradication Program, which leads the effort to rid the world of polio, said in a statement that the discovery highlights the importance of countries continuing to be on the lookout for polio, noting “any form of poliovirus anywhere is a threat to children everywhere.” “It is vital that all countries, in particular those with a high volume of travel and contact with polio-affected countries and areas, strengthen surveillance in order to rapidly detect any new virus importation and to facilitate a rapid response,” the statement said. “Countries, territories, and areas should also maintain uniformly high routine immunization coverage … to protect children from polio and to minimize the consequences of any new virus being introduced.” The polio eradication program is a partnership involving the World Health Organization, the United Nations Children’s Fund, the service group Rotary International, the Centers for Disease Control and Prevention and the Bill and Melinda Gates Foundation.

With six confirmed and two suspected cases, health officials are ramping up a vaccination push amid fears of a wider outbreak.  A polio outbreak centered in Jerusalem has prompted Israel’s return to the World Health Organization’s list of polio “outbreak countries.” Israel now appears along with 28 other countries on the WHO’s Global Polio Eradication Initiative’s list of countries with polio outbreaks, after being declared polio-free in 1988. Nations including Egypt, Iran, Ethiopia and Ukraine are also on the list of outbreak countries — places where the virus was halted but has resurfaced — while Afghanistan and Pakistan are considered endemic countries. Last month, the first case of polio in more than 30 years was confirmed in Jerusalem, spurring deep concerns and a renewed vaccination drive.  According to the latest Health Ministry figures, released last week, there have been six confirmed polio cases, all among unvaccinated patients. In addition, there is a high likelihood of another case in an unvaccinated child, and an eighth potential case that is being investigated. Traces of the disease have also been found in the sewage system in Jerusalem, Beit Shemesh, Tiberias and Modiin Illit.

Over the past month, more than 18,000 children in the Jerusalem area have received a polio vaccine dose as part of the ministry’s push to reach those who were unvaccinated or partially vaccinated. Like much of the world, Israel administers polio vaccines — spread out in multiple doses — to children as part of its standard vaccine regimen. Polio spreads mostly from person to person or through contaminated water. It attacks the nervous system and can sometimes paralyze people within hours. The disease mostly affects children under 5 and has been largely wiped out in wealthy countries. Dr. Sharon Alroy-Preis, the Health Ministry’s public health director, explained last week that during the years 2005-2013, polio vaccinations were scaled back as the disease was vanquished in the country and many babies did not get all the necessary doses. “We are definitely seeing an outbreak of polio in Israel,” Alroy-Preis said. “It reaches unvaccinated pockets and is spreading.” One Jerusalem child who was recently diagnosed with polio has weakness and paralysis on one side, she reported. “That is just the tip of the iceberg, under which there are many other infected children,” she assessed. Disease experts have warned of the real prospect of a resurgence of polio cases — in manageable numbers but enough to leave some children with long-term damage. Traces of the virus have occasionally been found in sewage samples in Israel, but have not resulted in any clinical cases for several decades.

The vaccine, designed to prevent harmful mutations, is seen as key to eradicating polio. A vaccine against a type of polio that is spreading in the Southern Hemisphere is expected to receive emergency approval before the end of the year. If it does, it will be the first time the World Health Organization has steered an unlicensed vaccine or drug through its emergency listing process. Wild polio has been almost eradicated. Only two countries — Afghanistan and Pakistan — still report cases. But a version of the virus that arose naturally from the weakened polio virus used in vaccination is increasing. What is called circulating vaccine-derived poliovirus (cVDPV) is increasing in both Afghanistan and Pakistan, as well as in the Philippines, Malaysia, Yemen and 19 African countries — with Chad, the Democratic Republic of the Congo and Côte d’Ivoire the worst affected in Africa.

So far in 2020, there have been more than 460 cases of vaccine-derived polio worldwide. This is more than 4 times the number detected by this time in 2019, which is a major problem for the 32-year, US$17-billion global campaign to wipe out the disease. Researchers who model polio infections say that for every known case, there are about 2,000 infections in the population. “Millions of people potentially have no immunity to the vaccine-derived virus, and that’s why we’re very concerned,” says Kathleen O’Reilly, an epidemiologist at the London School of Hygiene and Tropical Medicine who models polio infections. Independent scientific advisers to the World Health Organization (WHO) have been assessing a vaccine that is designed specifically to protect against cVDPV. This vaccine, a decade in the making, has been tested for safety and efficacy, but is not yet licensed and still has to undergo further trials. The WHO is in the last stages of considering whether to approve it more quickly, under what is called an emergency-use listing — a procedure that was created during the 2014–16 Ebola outbreak in West Africa, and which the agency is also preparing to use for coronavirus vaccines...

Published in Nature (Oct. 29, 2020):

https://doi.org/10.1038/d41586-020-03045-2

Many mass immunization efforts worldwide were halted this spring to prevent spread of the virus at crowded inoculation sites. The consequences have been alarming. As poor countries around the world struggle to beat back the coronavirus, they are unintentionally contributing to fresh explosions of illness and death from other diseases — ones that are readily prevented by vaccines. This spring, after the World Health Organization and UNICEF warned that the pandemic could spread swiftly when children gathered for shots, many countries suspended their inoculation programs. Even in countries that tried to keep them going, cargo flights with vaccine supplies were halted by the pandemic and health workers diverted to fight it.

Health officials are rushing a genetically engineered product into the field to counter uncontained outbreaks of vaccine-derived polio. To stem a growing polio crisis, health officials are accelerating the development of a new oral vaccine with plans for emergency approval and deployment in regions with active polio transmission as early as June 2020. The new vaccine, called nOPV2, might conclusively end the outbreaks, caused by the live virus in the vaccine reverting to a virulent form. But expedited approval means skipping the real-world testing of large clinical trials. Instead, key questions about the vaccine’s effectiveness will be answered in the field. “The nOPV strains have been tested in a small number of volunteers and we do not see reversion to neurovirulence,” says Vincent Racaniello, a virologist at Columbia University, “but when they are used for mass immunization of millions of individuals, rare events can become evident.”

Oral polio vaccine strains, originally developed by Albert Sabin in the 1950s, can in rare instances revert to virulence, spread, and paralyze children just like polio itself, a phenomenon first recognized in 2000. Because the Sabin vaccine had successfully eradicated wild type 2 poliovirus in 2015, health officials across the world quit administering it the following year. However, herd immunity had not been achieved before the cessation of the type 2 vaccine, which gave an opportunity for un-immunized people to later become infected by the virus that had begun reverting to virulence in people who had gotten the vaccine. With successive transmission through the unvaccinated, the vaccine strain can regain the virulence of wild polio. Nowadays, cases of polio caused by vaccine-derived strains outnumber those caused by the wild virus–and they continue to spread unchecked, most recently from the Phillipines to Malaysia. Vaccine-derived polio threatens as many as 210 million children globally, according to the World Health Organization. Using the reversion-prone Sabin type 2 vaccine to fight outbreaks caused more new outbreaks than it stopped, a virologist at the Centers for Disease Control and Prevention (CDC) told Science earlier this year. 

nOPV2, the new type 2 oral polio vaccine, has been genetically engineered to avoid the pitfalls of Sabin’s vaccine. The project is funded by the Gates Foundation and coordinated by PATH, a nonprofit developer of public health innovations, with scientific work taking place at the National Institute for Biological Standards and Control (NIBSC) in the UK, the University of California, San Francisco, the CDC, and the Food and Drug Administration. Poliovirus “evolves readily to any situation it finds,” says Andrew Macadam, a principal scientist at NIBSC and a designer of nOPV2. As RNA viruses, polio and polio vaccine strains evolve using mutation and recombination. Polio “has a polymerase that is not very accurate,” says Macadam, so mutations occur frequently during replication. More importantly for rapid adaptation, recombination allows the virus to incorporate RNA strands from other C type enteroviruses in human hosts that enable gains in virulence. These partners include all the Sabin strains and Coxsackievirus, for example. nOPV2 obstructs some key genetic routes to pathogenicity, believed to be controlled by “gatekeeper” mutations. In particular, a single point mutation at nucleotide 481 increases neurovirulence and actually occurs in most people soon after immunization. The pivotal change at 481 makes a return to virulence possible, according to Macadam. “The gatekeeper idea,” he explains, “is that it needs to revert at 481 before it can do anything else and then you can incorporate these other mutations” that cause the vaccine to become pathogenic. So nOPV2 developers modified 18 nucleotides near 481 in the poliovirus genome so that the well-known single substitution no longer opens the gate to virulence. This safeguard in turn is protected from wholesale replacement via recombination by relocating a gene necessary for replication to another part of the genome so that if the modifications near 481 are lost through recombination, the gene needed for replication will also be lost. As a result, reversion “requires two recombination events instead of one,” according to Macadam, one being the acquisition of a second copy of the replication gene and the other being the loss of the 481-related modifications. “Therefore, it’s less likely,” says Macadam. In addition, Macadam’s team outfitted nOPV2 with a higher-fidelity polymerase that introduces fewer errors during replication while another gene received alterations to decrease the virus’ propensity for recombination....

Health authorities here confirmed that the Davao River had been found positive of the polio virus, prompting them to order a massive polio vaccination drive next month, targeting all children in the city.

Dr. Josephine Villafuerte, City Health Officer, said the water samples earlier submitted to the Research Institute for Tropical Medicine (RITM) confirmed the presence of polio virus in the Davao River, prompting health authorities here to set in motion a massive vaccination drive that would begin next month to stop the spread of the virus.

“In October, there will be an outbreak response vaccination. Every children is targeted to be covered,” she said. Villafuerte, however, gave assurance that there was no confirmed polio case here yet.  She said Davao City, President Rodrigo Duterte’s hometown, would be among areas for a massive vaccination campaign aside from the National Capital Region (NCR), Lanao del Sur province, Central Luzon and Calabarzon (Cavite-Laguna-Batangas-Rizal and Quezon) provinces. Villafuerte said the City Health Office would involve the community in the fight against polio resurgence. All village officials would be gathered on Sept. 24 for a planning session.

Village chiefs, she said, should be at the forefront of the fight against polio resurgence and report cases of paralysis immediately. She added that village officials should also be responsible for proper human waste disposal. There was no need for resorts to shut down swimming pools, though, she added. But she cautioned the public against swimming in the city’s resorts until the waters were declared safe.  She added that swimmers, especially children, “may ingest contaminated water.” She also asked resort owners to make sure their water is clean. “They should disinfect the water,” she added.

Parents should be aware of the symptoms of polio like fever, fatigue, headache, vomiting, stiff neck and sudden floppiness of arms or legs. Villafuerte said if parents see these signs on their children, “please go to the doctor immediately.” Department of Health data showed that coverage of polio immunization in Davao City was only 72 percent from 2016 to 2018. Villafuerte said people who have had complete shots of polio vaccine need not worry.

Using two types of polio vaccines seems to provide stronger protection against the disease and may boost efforts to eradicate polio, a new study shows. The research involving nearly 1,000 children in India found that giving the Salk inactivated poliovirus vaccine (IPV) to those who had already been given the Sabin live-attenuated oral poliovirus vaccine (OPV) appeared to improve their immunity to the virus that causes polio. The findings, reported in the Aug. 22 issue of the journal Science, could prove crucial in eliminating the world's remaining pockets of polio in places such as Iraq and Syria.

"This study revolutionized our understanding of IPV and how to use it in the global eradication effort to ensure children receive the best and quickest protection possible from this disease," study senior author Dr. Bruce Aylward, assistant director-general for Polio, Emergencies and Country Collaboration at the World Health Organization, said in a journal news release. "IPV should be used to accelerate the eradication of the virus in populations that have limited access to vaccination," study author Dr. Hamid Jafari, WHO's director for polio operations and research, said in the news release. "The study has also provided the evidence for use of IPV among travelers to limit further international spread of the virus."

Since polio vaccine was developed in the 1950s, efforts to eradicate polio have relied mainly on OPV rather than IPV. However, these findings show that giving both vaccines to patients may be the best approach. "The global eradication effort is at a critical crossroad," Jafari said. "Endemic polio is increasingly geographically restricted to populations in insecure and inaccessible areas. Yet the virus in these areas persists with incredible tenacity and threatens the increasingly vulnerable populations in polio-free countries with weak or conflict-affected health systems."

An outbreak of polio in 1950s Denmark led one hospital to pioneer mechanical ventilation, constant monitoring of vital signs and other innovations that are saving lives to this day. The COVID-19 pandemic has brought home the central role of intensive care units (ICUs) in saving the lives of those in critical condition in hospitals today. Yet if you asked most people where the ICU concept came from, few would know that it was an outgrowth of a polio epidemic in Denmark. In her brilliant new book, Hannah Wunsch, an anaesthesiologist and critical-care-medicine specialist at the University of Toronto, Canada, traces the origins of the modern ICU to 1952 and the Blegdam hospital in Copenhagen — something she has written about before in Nature (go.nature.com/45B6snd). There, a series of innovations arose out of dire need, including positive-pressure ventilation (the precursor to mechanical ventilators), blood-gas measurements for pH and carbon-dioxide levels and close monitoring by an interdisciplinary team of nurses, doctors (notably anaesthesiologists), pharmacists and others. The treatment of one patient, a 12-year-old girl named Vivi Ebert who presented with bulbar paralytic poliomyelitis — in which poliovirus infects the brainstem — forms the centrepiece of Wunsch’s book. Of the first 31 people to be admitted to the Blegdam in the summer of 1952 with paralytic or respiratory polio symptoms, 87% died, 70% within three days. Thanks to interventions including manual ventilation, supervised by anaesthesiologist Bjørn Ibsen, Ebert survived another twenty years, eventually succumbing to pneumonia at the age of 32.

In those early days it took 50 people to provide the muscle power required for round-the-clock ventilation for 6–8 people with paralytic polio. The hospital’s initial success led to more than 1,500 medical and dental students being employed as manual ventilators for patients admitted in the summer and autumn of 1952. Eventually, ‘iron lungs’ — mechanical ventilator machines — took the place of humans, and the ICU concept was built, focusing on the sickest patients, who required a breathing machine and constant monitoring. Over the next few years, the use of ICUs expanded to the treatment of people with major trauma, shock, tetanus and a variety of other acute, life-threatening conditions. The treatment of polio, the main story of The Autumn Ghost, has rich parallels to the COVID-19 pandemic. In the 1950s, the prevailing hypothesis about the spread of polio was that the virus was inhaled into the body’s upper airways. It took decades for the gastrointestinal transmission route — oral contact with the faeces of an infected person — to become accepted. Similarly, for COVID-19, there was an initial fixation on liquid droplets on surfaces and in the air as the main means of transmission, whereas it was determined later that it was spread predominantly within tiny droplets or aerosols in the air. Furthermore, a substantial proportion of both poliovirus and SARS-CoV-2 infections were asymptomatic. And both viruses have long-term consequences: for polio, not only potential paralysis, but also the debilitating neuromuscular syndrome that can occur decades later. Long COVID affects 10–12% of infected individuals, with a variety of enduring symptoms that can be incapacitating with potentially more longer-term effects that are yet unknown.

Polio taught us about the efficacy of positive-pressure ventilation for those having difficulty with breathing. With COVID-19, we learnt that ventilating patients while they were lying face down was crucial to good outcomes. For poliovirus, large, randomized trials of γ-globulin — a substance derived from bone marrow and lymph gland cells containing antibodies thought to help fight the virus — had some success in the years before a vaccine became available. For COVID-19, large observational studies were undertaken of treatment with blood plasma from those who had recovered, although a lack of randomized studies makes it hard to assess the treatment’s effectiveness. Perhaps the most striking difference between the two viruses is how long it was before a vaccine was developed. For SARS-CoV-2, it was 10 months from sequencing the virus to producing results from large, randomized trials demonstrating high levels of vaccine efficacy. Large-scale distribution quickly followed. Poliovirus was identified as the pathogen for polio in 1908, but it wasn’t until 1955 that US virologist Jonas Salk developed the first effective vaccine to be delivered by means of an injection, followed quickly by an oral vaccine developed by US physician and microbiologist Albert Sabin in 1961.

Wunsch provides a detailed history of polio, the iron lung, the rise of the field of anaesthesiology, the development of the Salk and Sabin vaccines and the work at Denmark’s Statens Serum Institute, a medical laboratory in Copenhagen, in manufacturing and rolling out the Salk vaccine ten days after it was announced. But she really hits her stride when she describes those whose lives were saved. Another early patient treated by tracheostomy and hand ventilation at the Blegdam hospital was 26-year-old Rosa Abrahamsen. She was a poet, and her beautiful poems, translated into English for the book, begin several chapters. The Autumn Ghost might have been improved with a timeline, given that it bounces back and forth at many points. Although the extraordinary progress and innovations made in Denmark were central to the development of ICUs, the contribution of parallel efforts from around the world might not have been adequately highlighted. When I was at the University of Virginia in Charlottesville in the 1970s, I worked as a respiratory technician on the night shift, maintaining Engström ventilators (alluded to in the book as the “Rolls Royce of artificial respiration”) for patients in the ICU. I had no idea how those ventilators, or indeed ICUs, came to be. But seeing many patients ‘come back to life’ inspired me to go to medical school. Only five decades later, thanks to reading this book, have I learned the remarkable background to these profound innovations — and how the poliovirus radically transformed the future of medicine.

Health department says it's working with Jerusalem 'to ensure a coordinated response' after 4 cases of virus recently detected in Safed. The State of New York’s health department called for residents to get vaccinated against polio before traveling to Israel, where several children have recently tested positive for the virus. In a statement Friday, the New York Department of Health noted the four cases diagnosed in the northern city of Safed earlier this month, a year after a small outbreak of the disease in the country. It called on New Yorkers “to get fully immunized” before flying to Israel or other countries with polio. Health officials in New York have been in touch with their Israeli counterparts “to ensure a coordinated response,” the statement said, adding that travelers should adhere to guidelines from the US Center for Disease Control. Besides Israel, the statement noted the CDC has issued precautions against polio before traveling to the United Kingdom, Ukraine, Afghanistan, Pakistan, Indonesia, Nigeria, Côte d’Ivoire and several other central African countries.

Polio is a viral disease that mainly affects children and can cause disability, paralysis and death. Today, polio vaccinations are standard for children and are an effective preventive measure, but vaccine skepticism has enabled the disease to pop up from time to time. The outbreak in Israel last March, which came after the first case of polio in 33 years was discovered in the country, prompted a vaccination drive to combat the disease. The finding landed Israel on the World Health Organization’s Polio Eradication Initiative’s list of countries with outbreaks, after it was declared polio-free in 1988. Following the cases detected earlier this month, the Health Ministry cited evidence of polio spreading in sewage systems and said over 150,000 Israeli children are unvaccinated against the virus.

Before its discovery in New York’s wastewater, the virus made a series of ominous appearances around the world.  At the beginning of this year, there was a thrum of excitement among global health experts: Eradication of polio, a centuries-old foe that has paralyzed legions of children around the globe, seemed tantalizingly close. Pakistan, one of only two countries where wild poliovirus still circulates, had not recorded cases in more than a year. Afghanistan had reported only four. But eradication is an uncompromising goal. The virus must disappear from every part of the world and stay gone, regardless of wars, political disinterest, funding gaps or conspiracy theories. New signs of the virus in a single country can derail the effort.  In polio’s case, there were several ominous setbacks. Malawi in February announced its first case in 30 years, a 3-year-old girl who became paralyzed following infection with a virus that appeared to be from Pakistan. Pakistan itself went on to report 14 cases, eight of them in a single month this spring. In March, Israel reported its first case since 1988. Then, in June, British authorities declared an “incident of national concern” when they discovered the virus in sewage. By the time New York City detected the virus in wastewater last week, polio eradication seemed as elusive as ever. “It’s a poignant and stark reminder that polio-free countries are not really polio-risk free,” said Dr. Ananda Bandyopadhyay, deputy director for polio at the Bill & Melinda Gates Foundation, the largest supporter of polio eradication efforts.  The virus is always “a plane ride away,” he added. Polio is a highly contagious and sometimes deadly enemy, capable of ravaging the nervous system and causing paralysis within hours. Those who recover could relapse and become seriously ill years later.

The virus multiplies in the intestine for weeks and could spread through feces or contaminated food or water — for example, when an infected child uses the toilet, neglects washing hands and then touches food.  For decades the virus terrorized families, causing paralysis among more than 15,000 American children each year and hundreds of thousands more worldwide. Its retreat is a triumph of vaccination. After the first vaccine arrived in 1955, the number of cases dropped precipitously, and by 1979 the United States was declared polio-free. Although the United States and Britain have high immunization rates, they also have pockets of low immunity that allow the virus to flourish. In those communities, all unvaccinated people — not just children — are at risk. If polio continues to spread in the United States for a year, the country may lose its polio-free status under W.H.O. guidelines. The Covid-19 pandemic left many other countries vulnerable to a resurgence of polio: It disrupted vaccination drives for months and diverted staff and resources away from prevention programs, resulting in the worst backslide in immunization rates in 30 years. “The moment you take your eye off the ball, you know that the virus will simply reappear,” said Aidan O’Leary, director for polio eradication at the World Health Organization. “We have to literally face down every single chain of transmission that we can identify.”  Aid organizations first aspired to eradicate polio in 1988 and poured billions of dollars into the Global Polio Eradication Initiative, a consortium of six partners, including the Gates Foundation, the W.H.O. and the Centers for Disease Control and Prevention. Despite the recent cases, the progress is unmistakable: Global cases of polio have fallen by 99 percent — from 350,000 cases of paralysis in 1988 to about 240 so far this year.

A recent case in a New York suburb has reignited concerns over the disease.  During the slog of yet another Covid wave, and mounting monkeypox anxieties, health officials reported a case of polio in a New York suburb in July— the first detected in the United States in nearly a decade. State health officials said that polio was detected in an unvaccinated person in Rockland County, New York, and that the virus had been found in county wastewater samples in June, as well as in wastewater samples in two different locations in Orange County, New York, in June and July. On Aug. 12, health officials announced that poliovirus had been detected in sewage samples in New York City, indicating that the virus is likely circulating there too. These occurrences, as well as reports that health officials in Britain had detected evidence of poliovirus in sewage samples in London, have reignited polio concerns. However, experts said that people who are vaccinated against polio do not need to change their daily behaviors or panic about the disease. Here’s what you need to know.

The health department said it is still investigating the virus' origin, after finding eight of the positive wastewater samples are genetically linked. New York state health officials have found indications of additional cases of polio virus in wastewater samples from two different counties, leading them to warn that hundreds of people may be infected with the potentially serious virus.  Just two weeks ago, the New York Health Department reported the nation's first case of polio in almost a decade, in Rockland County, north of New York City. Officials said that case occurred in a previously healthy young adult who was unvaccinated and developed paralysis in their legs. Since then, three positive wastewater samples from Rockland County and four from neighboring Orange County were discovered and genetically linked to the first case, the health department said in a press release on Thursday, suggesting that the polio virus is being spread within local communities. The newest samples were taken from two locations in Orange County in June and July and one location in Rockland County in July. "Based on earlier polio outbreaks, New Yorkers should know that for every one case of paralytic polio observed, there may be hundreds of other people infected," State Health Commissioner Dr. Mary T. Bassett said. "Coupled with the latest wastewater findings, the Department is treating the single case of polio as just the tip of the iceberg of much greater potential spread. As we learn more, what we do know is clear: the danger of polio is present in New York today."  The health department reiterated that it is still investigating the virus' origin, and said that it is not yet clear whether the infected person in Rockland County was linked to the other cases.

Polio is "a serious and life-threatening disease," the state health department said. It is highly contagious and can be spread by people who aren't yet symptomatic. Symptoms usually appear within 30 days of infection, and can be mild or flu-like. Some people who are infected may become paralyzed or die. Before the polio vaccine was introduced in the 1950s, thousands of Americans died in polio outbreaks and tens of thousands, many of them children, were left with paralysis. After a successful vaccination campaign, polio was officially declared eradicated in the U.S. in 1979.   Unvaccinated New Yorkers are encouraged to get immunized right away, the health department said. Unvaccinated people who live, work or spend time in Rockland County, Orange County and the greater New York metropolitan area are at the greatest risk. Most school-aged children have received the polio vaccine, which is a four-dose course, started between 6 weeks and 2 months of age and followed by one shot at 4 months, one at 6 to 12 months, and one between the ages of 4 and 6. According to the health department, about 60% of children in Rockland County have received three polio shots before their second birthday, as have about 59% in Orange County — both below the 79% statewide figure.  According to the CDC's most recent childhood vaccination data, about 93% of 2-year-olds in the U.S. had received at least three doses of polio vaccine. Meanwhile, adults who are not vaccinated would receive a three-dose immunization, and those who are vaccinated but at high risk can receive a lifetime booster shot, according to the health department.  The vaccine is 99% effective in children who receive the full four-dose regime, health officials said. "It is concerning that polio, a disease that has been largely eradicated through vaccination, is now circulating in our community, especially given the low rates of vaccination for this debilitating disease in certain areas of our County," Orange County Health Commissioner Dr. Irina Gelman said. "I urge all unvaccinated Orange County residents to get vaccinated as soon as medically feasible." Rockland County Department of Health Commissioner Dr. Patricia Schnabel Ruppert issued a similar statement, calling on people who are not vaccinated to get the shots "immediately." Polio has rarely appeared in the U.S. since it was declared eradicated over 40 years ago. The last reported case was brought by a traveler in 2013, according to The Associated Press.

Health officials say parents should ensure their children have been vaccinated against the disease.  The virus that causes polio has been detected in a concerning number of sewage samples in London, health officials have said. The disease was common in the UK in the 1950s but was eliminated by 2003. The UK Health Security Agency (UKHSA) says it was probably imported to London by someone who was recently vaccinated overseas with a live form of the virus. It says the risk is low, but parents should ensure their children have been fully immunised against the disease. "Most of the UK population will be protected from vaccination in childhood, but in some communities with low vaccine coverage, individuals may remain at risk," said Dr Vanessa Saliba, consultant epidemiologist at UKHSA. An inactivated polio vaccine is used in the UK as part of the routine childhood programme. It is given to children three times before the age of one, and then again at three and 14 years of age.  Take-up of the first three doses is about 86% in London, well below target levels, with the rest of the UK over 92%. Health authorities have now declared a national incident and informed the World Health Organization (WHO) of the situation.

Malawi has declared a polio outbreak after a case was detected in a young child in the capital Lilongwe, the first case of wild poliovirus in Africa in more than five years, the World Health Organization (WHO) said. Africa was declared free of indigenous wild polio in August 2020 after going 4 years without a recorded case. Because testing showed that the new case detected in Malawi is linked to a strain from Pakistan, it does not affect Africa’s polio-free status, WHO noted.  “As long as wild polio exists anywhere in the world, all countries remain at risk of importation of the virus,” Matshidiso Moeti, MD, MPH, WHO’s regional director for Africa, said in a statement. The incidence of wild polio has declined nearly 100% since 1988. It continues to be endemic in only two countries, Afghanistan and Pakistan, although only six total cases have been detected in those two countries since the beginning of 2021, according to the Global Polio Eradication Initiative (GPEI).  The GPEI reported that the child in Malawi is a 3-year-old girl who experienced an onset of paralysis on Nov. 19 last year. It said the virus was genetically linked to a strain detected in Pakistan’s Sindh province in October 2019.

“Detection of [wild poliovirus] outside the world’s two remaining endemic countries, Pakistan and Afghanistan, is a serious concern and underscores the importance of prioritizing polio immunization activities,” the GPEI said in a statement. “Until polio is fully eradicated, all countries remain at risk of importation and must maintain high vaccination coverage to protect all children from polio.” According to WHO, health authorities in Malawi have responded to the case with increased surveillance and supplemental immunizations, supported by WHO. Neighboring countries have also ramped up surveillance. A GREI rapid response team based in WHO’s Africa office is deploying to Malawi to support efforts. “Any case of wild polio virus is a significant event, and we will mobilize all resources to support the country’s response,” Modjirom Ndoutabe, MD, polio coordinator at WHO’s Regional Office for Africa, said in a statement.

After a 32-year campaign to rid the African continent of wild poliovirus, the World Health Organization declared Africa entirely polio-free. Nobody will ever know the identity of the thousands of African children who were not killed or paralyzed by polio this year. They would have been hard to keep track of no matter what because in ordinary times, they would have followed thousands last year and thousands the year before and on back in a generations-long trail of suffering and death. Instead, no African children were claimed by polio this year or last year or the year before. It was in 2016 that the last case of wild, circulating polio was reported in Nigeria—the final country on the 54-nation African continent where the disease was endemic. And with a required multi-year waiting period now having passed with no more cases, the World Health Organization today officially declared the entirety of Africa polio-free. A disease that as recently as the late 1980s was endemic in 125 countries, claiming 350,000 children per year, has now been run to ground in just two remaining places, Pakistan and Afghanistan, where there have been a collective 102 cases so far in 2020. That’s 102 too many, but there is no denying the scope of the WHO announcement. “Today’s victory over the wild poliovirus in the African region is a testament to what can happen when partners from a variety of sectors join forces to accomplish a major global health goal,” says John Hewko, general secretary and CEO of Rotary International. “[It is] something the world can and should aspire to during these turbulent times.”

It was Rotary, an international nonprofit service organization, that kicked off the polio endgame in 1988 with the launch of the Global Polio Eradication Initiative (GPEI). That program aimed to leverage the power of Rotary’s 35,000 clubs and 1.22 million members in 200 countries and territories worldwide to make polio only the second human disease—after smallpox—to be pushed over the brink of extinction. The job was made easier by the partners Rotary immediately attracted: the WHO, the U.S. Centers for Disease Control and Prevention (CDC) and UNICEF. The Bill and Melinda Gates Foundation joined in 2007, followed by Gavi, the Vaccine Alliance, just last year. The 32-year initiative has depended on volunteer workers and charitable donations, which together have produced an army of 20 million field workers administering vaccines to over 2.5 billion children at a cost of $17 billion. Some countries were a lighter lift than others. In the U.S. the disease was eradicated in 1979, well before the GPEI even began its work. Other nations followed: In 1994 the Americas were declared polio-free. Europe as a whole got a clean bill of health in 2002, when all 53 countries in the WHO’s designated European region were declared free of the virus. Massive vaccination efforts began in India in 1997, which eradicated the virus in 2014. 

How Polio Was Eradicated from the African Continent

But Africa, with its vast sprawl of village populations, long distances to urban hospitals, spotty infrastructure like adequate roads and reliable “cold chains”—refrigerated transport networks to keep vaccines viable—was always going to present special challenges. In 1996, when the case count on the continent regularly reached 75,000 victims every year, South African President Nelson Mandela partnered with Rotary to launch the “Kick Polio Out of Africa” Campaign, and the group scrambled fast—or as fast as was possible with so many children to vaccinate on so vast a land mass. In 2000, the first synchronized campaigns began in 17 countries, with 76 million children being vaccinated by tens of thousands of volunteers. The work fanned out across the continent from there, including an especially heavy push from 2008 to 2010, when an outbreak in 24 countries in western and central Africa was met by a large-scale, multi-national vaccination of 85 million children. Finally, Nigeria stood alone as the only African nation where the disease was still endemic, in part because of resistance by religious leaders in the northern part of the country who objected western interference in local affairs and claimed that the vaccine was unsafe. That opposition broke down, partly thanks to Muhammad Sanusi II, the Emir of the city of Kano—a hereditary leader descended from a ruling family—who appeared at a public ceremony before the kick off of a seasonal vaccination campaign in 2016, called for a vial of polio vaccine to be brought to the stage, and with the audience watching, broke its seal and drank down its entire contents. That year, the country recorded its last case of polio, and this year, Nigeria’s WHO certification is the reward for its efforts....

Prophylactic vaccination is the most effective intervention to protect against infectious diseases. The commonly accepted paradigm is that immunization with both attenuated virus (live but with substantially reduced virulence) and inactivated (killed virus particles) vaccines induces adaptive and generally long-term and specific immunity in the form of neutralizing antibodies and/or activating pathogen-specific cellular immune responses. However, an increasing body of evidence suggests that live attenuated vaccines can also induce broader protection against unrelated pathogens likely by inducing interferon and other innate immunity mechanisms that are yet to be identified. The stimulation of innate immunity by live attenuated vaccines in general, and oral poliovirus vaccine (OPV) in particular, could provide temporary protection against coronavirus disease 2019 (COVID-19).

OPV was developed by Albert Sabin in the 1950s and consists of live attenuated polioviruses of the three serotypes. Early clinical studies showed that besides protecting against poliomyelitis, OPV reduced the number of other viruses that could be isolated from immunized children, compared with placebo recipients. Additional evidence of nonspecific effects of OPV came from the 1959 poliomyelitis outbreak in Singapore caused by type 1 poliovirus that was successfully stopped by the use of monovalent OPV that contained only type 2 poliovirus (1). Monovalent OPVs do not induce cross-neutralizing antibodies that target other virus serotypes, so the most plausible explanation was viral interference, which presumably is mediated by innate immunity.

Large-scale clinical studies of OPV for nonspecific prevention of diseases were carried out in the 1960s and 1970s. These involved more than 60,000 individuals and showed that OPV was effective against influenza virus infection, reducing morbidity 3.8-fold on average (2, 3). OPV vaccination also had a therapeutic effect on genital herpes simplex virus infections, accelerating healing. OPV not only demonstrated positive effects against viral infections but also had oncolytic properties, both by directly destroying tumor cells and by activating cellular immunity toward tumors (2). These observations were among the first examples of viral oncotherapy, which is being actively pursued.

Published in Science (June 12, 2020):

https://doi.org.10.1126/science.abc4262

As the global effort to eradicate polio gets tantalizing close to its goal, the program is running in to new challenges. One of the biggest obstacles this year is the proliferation of so-called "vaccine-derived" polio outbreaks. Conventional polio caused by the traditional form of the disease is now only occurring in two countries in the world — Afghanistan and Pakistan. The World Health Organization calls this form "wild" polio and there've been roughly 100 cases so far this year. This is a tiny number compared to the 350,000 cases that occurred globally before the Global Polio Eradication Initiative was launched in 1988.

But what's troubling now is that there are currently more kids being paralyzed by cases of vaccine-derived polio than by the original "wild" variety. "We have seen a lot more countries impacted this year than last year," says Dr. John Vertefeuille, the head of polio eradication at the U.S. Centers for Disease Control and Prevention. There've been outbreaks this year in the Philippines, China, Myanmar, Pakistan and a half a dozen African countries. "Because of the rising number of individual outbreaks," Vertefeuille says. "The CDC has taken a decision to do a surge staffing effort focusing on Africa." He says the CDC is in the midst of sending up to 100 additional personnel to Africa to help track, manage and wipeout vaccine-derived polio outbreaks over a six-month period.

Currently around the world, all children are supposed to get vaccinated against polio. In the U.S. and other wealthy nations, kids get 4 injections of inactivated polio vaccine spread out over their first 7 years of life. This injectable vaccine does not contain live virus, so it does not and cannot cause vaccine-derived polio. In lower income countries with weaker health systems, an oral vaccine containing a live but weakened version of the polio virus is used. It's cheap and easy to administer through a few drops in a child's mouth. In the early days of polio eradication, this live oral vaccine also had the added benefit that it could circulate in a community just like the real, wild virus. In places with poor sanitation, wild polio and the virus in the oral vaccine can spread from sewage to drinking water. At first this was great. Kids who hadn't been vaccinated by health workers ended up getting exposed to the oral vaccine and protected against wild polio because of their lousy drinking water supplies. But over time the virus from the oral vaccine starts to regain strength and if it's allowed to circulate long enough, it reverts back to the point that it can cause paralysis just like the original virus.

"We actually do genetic analysis so that we can understand the closest relative of each (virus) detection that we see globally," says Vertefeuille at the CDC. And in these vaccine-derived outbreaks, they can see that the virus that's paralyzing kids is directly linked to the vaccine that was distributed earlier. "You have to keep vaccinating all the children so you won't have any paralyzed children," Noymer says, "But the more you vaccinate, the more live virus continues to circulate. And the minute you step off the treadmill, you get some paralyzed kids." One way to get off that treadmill would be to get rid of the live oral vaccine and switch to the not-live, injectable vaccine used in the United States. The Global Polio Eradication Initiative has tried to move in that direction but there are several challenges. First there just isn't enough supply globally of the injectable vaccine to cover the hundreds of millions of kids in low income countries. Training vaccinators to give injections is much harder than training them to give two drops in to a child's mouth. Also the vaccines work slightly differently — with the oral version doing a better job of breaking chains of transmission and stopping outbreaks....

Defending against viruses is one of the thorniest problems in medicine. Vaccines have been a major success story but can still only fend off a fraction of known viruses. They work by “teaching” our immune system to recognize a specific virus so it can mount an effective immune response if it spots that invader in future. Another approach is the use of antivirals, which prevent viruses from replicating and can be used to treat a current infection if administered quickly. Developing safe antivirals is difficult, however, because viruses hijack the host’s own cellular machinery in order to replicate, so interfering can also harm host cells.

A problem for both approaches is the huge diversity of viral pathogens. For instance, the viral group responsible for at least half of all cases of the common cold—rhinovirus–has at least 160 different types. Developing more than 100 vaccines to cure one illness is obviously not practical, and in any case, other viruses also cause colds. Complicating matters further, many viruses can mutate in ways that make them resistant to drugs or capable of overcoming immunity. All of which is why an important goal in virology is the development of “broad spectrum” antivirals that are effective against many viruses simultaneously.

In a study published Monday in Nature Microbiology, microbiologist Jan Carette of Stanford University and his colleagues report they have found a human gene that produces a protein essential to the function of numerous enteroviruses, a genus that includes rhinoviruses. Experiments in human cells and mice showed a range of enteroviruses cannot replicate without this host protein. The work could pave the way for antivirals effective against multiple illnesses—including most cases of the common cold—and sheds new light on how viruses exploit their host’s own cellular material.  Carette and his colleagues have “done a tour de force here, to find this gene and characterize it,” says Ann Palmenberg, a virologist at the University of Wisconsin-Madison, who provided some advice and materials for the study but was not directly involved in it. “It’s a beautiful piece of work.”

Enteroviruses also include poliovirus, coxsackievirus (which causes myocarditis, or heart inflammation) and EV-D68, a virus that has been linked to acute flaccid myelitis . To search for commonalities between these viruses, the researchers used cutting-edge gene-editing technology to inactivate single genes from human cells grown in a lab dish. First they created a bank of cells that each lacked a different gene, spanning the whole human genome. Then they infected these cells with two enteroviruses: EV-D68 and a “type-C” rhinovirus called RV-C15. The latter is a fairly newly discovered rhinovirus type that can seriously exacerbate asthma symptoms and increase the risk of infected infants developing asthma and chronic obstructive pulmonary disease. Although they are both enteroviruses, EV-D68 and RV-C15 are relatively distant relations that mostly make use of different host-cell proteins. The team then looked at which genes were missing in cells that continued to flourish after infection, focusing on the few whose absence thwarted both viruses. In addition to two genes that produce proteins known to be needed by enteroviruses, one little known one stood out: SETD3, which makes a protein of the same name. Carette and his colleagues next investigated how widely enteroviruses, in general, depend on the protein SETD3. They created cells lacking SETD3 and infected them with seven viruses representative of the different species of human enteroviruses: one of each of the three types of rhinovirus (A, B and C), poliovirus, two types of Coxsackievirus and EV-D68. None of these could flourish in SETD3-deficient cells—their replication rate was reduced 1,000-fold as compared with control cells that possessed the gene....

Original findings published on September 16, 2019 in Nature Microbiology:

https://doi.org/10.1038/s41564-019-0551-1