Virus World

Versiti’s blood tests screen for antibodies that may make typical clot treatments harmful to help healthcare providers choose alternative therapies.  Following international probes into rare blood clots among recipients of Johnson & Johnson and AstraZeneca’s COVID-19 vaccines, blood testing company Versiti has put forward a suite of antibody tests to help identify patients that may be at risk. While these cases only number in the dozens among the millions of shots administered worldwide, one of the more dangerous aspects of these potentially severe clots—known as cerebral venous sinus thrombosis—is that the typical anticoagulation treatment can make matters worse. The blood thinner heparin is often used to treat blood clots, but in patients carrying certain platelet-activating antibodies, heparin can trigger harmful drops in platelet counts that could lead to spontaneous bleeding, worsening of their original clots and other complications, according to the Centers for Disease Control and Prevention (CDC).  

Versiti’s blood tests screen for these antibodies, to help healthcare providers choose alternative anticoagulation therapies.  They include an ELISA diagnostic for the PF4, heparin-dependent antibody, followed by additional heparin-induced thrombocytopenia testing or serotonin release assays, depending on the initial result.  The company also offers antibody identification panels if the patient shows low platelet counts in a standard blood draw. The American Society of Hematology recommends testing for PF4 antibodies ahead of treatment for vaccine-induced thrombotic thrombocytopenia, which it describes as an evolving disorder based on limited data.  After a 10-day pause on the use of the J&J vaccine in the U.S.—while the FDA and other agencies reviewed safety data, including the deaths of three recipients—a CDC advisory panel last week recommended restarting nationwide distribution. The shot, like AstraZeneca’s, will carry warnings about rare and severe blood clots and guidance for proper treatment. Both use adenovirus-based vectors to deliver the vaccine’s instructions into human cells.

Versiti's Press Release (April 27, 2021):

https://www.versiti.org/newsroom/news-releases/versiti-unveils-new-testing-options-for-vaccine-in 

It comes after a review of all currently available evidence into extremely rare cases of unusual blood clots in some vaccinated people.

• The Oxford-AstraZeneca shot has been dogged by safety concerns in recent weeks, with several European countries briefly suspending their use of the vaccine last month.
• The World Health Organization, the U.K.’s medicines regulator and the International Society on Thrombosis and Hemostasis have all said that the benefits of administering the Oxford-AstraZeneca shot far outweigh the risks.
• AstraZeneca has previously said its studies have found no higher risk of blood clots as a result of its vaccine.

LONDON — Europe’s medicines regulator on Wednesday announced a possible link between the coronavirus vaccine developed by AstraZeneca and the University of Oxford and rare blood clotting issues in adults who received the shot. It comes after a review of all currently available evidence into extremely rare cases of unusual blood clots in some vaccinated people. The Oxford-AstraZeneca shot has been dogged by safety concerns in recent weeks, with several European countries briefly suspending their use of the vaccine last month. The European Medicines Agency said on March 31 that it had found the shot to be safe and effective, but added it could not rule out the possibility of a causal link between the vaccine and clotting events so would continue to investigate. The World Health Organization, the U.K.’s medicines regulator and the International Society on Thrombosis and Hemostasis have all said that the benefits of administering the Oxford-AstraZeneca shot far outweigh the risks. AstraZeneca has previously said its studies have found no higher risk of blood clots as a result of its vaccine. Most countries have since resumed use of the shot but many have suspended inoculations across certain age groups. A senior official at Europe’s medicines regulator reportedly said Tuesday that there is a clear “association” between the Oxford-AstraZeneca vaccine and very rare blood clots in the brain, though the direct cause was not yet known. In an interview with Italian newspaper Il Messaggero published Tuesday, Marco Cavaleri, chair of the EMA’s vaccine evaluation team, said: “In my opinion we can now say it, it is clear that there is an association with the vaccine. However, we still do not know what causes this reaction.” The EMA subsequently denied it had established any link between the Oxford-AstraZeneca shot and rare blood clots in a statement to Agence France-Presse.

UK vaccine trial in children paused

Federal health officials called for a halt in the use of the company’s coronavirus vaccine while they study serious illnesses that developed in six American women.

WASHINGTON — Injections of Johnson & Johnson’s coronavirus vaccine came to a sudden halt across the country on Tuesday after federal health agencies called for a pause in the vaccine’s use as they examine a rare blood-clotting disorder that emerged in six recipients. All six were women between the ages of 18 and 48, and all developed the illness within one to three weeks of vaccination. One woman in Virginia died, and a second woman in Nebraska has been hospitalized in critical condition. More than seven million people in the United States have received Johnson & Johnson shots so far, and another 10 million doses have been shipped out to the states, according to data from the Centers for Disease Control and Prevention. “We are recommending a pause in the use of this vaccine out of an abundance of caution,” Dr. Peter Marks, the director of the Food and Drug Administration’s Center for Biologics Evaluation and Research, and Dr. Anne Schuchat, the principal deputy director of the C.D.C., said in a joint statement. “Right now, these adverse events appear to be extremely rare.” While they framed the move as a recommendation to health practitioners, the impact was immediate. By Tuesday evening, every state, the District of Columbia and Puerto Rico had announced a pause in Johnson & Johnson vaccine injections.  The same went for the U.S. military, federally run vaccination sites, and CVS and Walgreens, two pharmacy giants that participate in the federal program, officials said. Rite Aid, Walmart and Publix also announced that they had paused Johnson & Johnson injections.

Beyond American shores, Johnson & Johnson said it would delay the rollout of its vaccine in Europe, where several countries were poised to start administering it this week. South Africa, devastated by a more contagious variant of the virus that emerged there, also suspended use of the vaccine. Australia announced it would not purchase any doses. The Biden administration tried to portray itself as well prepared for the setback. President Biden said he would meet his goal to have enough doses to vaccinate every American adult who wanted it by the end of next month. “There is enough vaccine, that is basically 100 percent unquestionable, for every single, solitary American,” he insisted. The reaction prompted an intense debate among public health experts about whether guarding against such a rare disorder was worth the cost. Scores of vaccine appointments were canceled this week, and some public health officials feared that by fueling vaccine hesitancy and conspiracy theorists, the pause could prompt fewer Americans to get vaccinated — and expose them to far more risk.  Others said the F.D.A. and the C.D.C. simply had no choice. “It’s incredibly challenging, but to ignore it would have been worse,” said Rachael Piltch-Loeb, an expert in health risk communication at the N.Y.U. School of Global Public Health. If the public suspected that the government was concealing serious potential side effects, she said, far more people might decide against vaccination.

Dr. Janet Woodcock, the acting commissioner of the F.D.A., said at a news conference that the pause might last only “a matter of days,” although she said that depended on “what we learn in the next few days.” Dr. Schuchat said the pause was enacted partly to “prepare the health care system to recognize and treat patients appropriately.” Scientists with the F.D.A. and the C.D.C. will jointly examine possible links between the vaccine and the disorder and determine whether the F.D.A. should continue to allow emergency use of the vaccine for all adults or modify the authorization, possibly by limiting the vaccine to certain population groups. An emergency meeting of the C.D.C.’s outside vaccine advisory committee has been scheduled for Wednesday. Despite Mr. Biden’s assurance, the pause will complicate the nation’s vaccination efforts at a time when many states are confronting a surge in new cases and seeking to address vaccine hesitancy. Regulators in Europe and elsewhere are concerned about a similar issue with another coronavirus vaccine, developed by AstraZeneca and Oxford University researchers. At the news conference, Dr. Marks drew a link between the two vaccines, saying the clotting cases were “very, very similar.” The vaccines are based on similar technology, but AstraZeneca’s has not yet been authorized for emergency use in the United States....

Johnson & Johnson release on the above issue (April 13):

https://www.jnj.com/johnson-johnson-statement-on-covid-19-vaccine-updated 

FDA-CDC Announcement on Janssen's vaccine:

https://www.fda.gov/news-events/press-announcements/joint-cdc-and-fda-statement-johnson-johnson-covid-19-vaccine 

Isolating the cause has allowed scientists to develop a treatment for the blot clots once diagnosed.

• Scientists at Greifswald University Hospital said in a statement Friday that in rare instances, the vaccine has created an antibody that triggered the formation of blood clots in the brain.
• The findings confirm those from an independent team in Norway earlier this week.
• Isolating the cause has allowed scientists to identify how to treat patients who have developed the blot clots, by giving them intravenous immunoglobulin, which targets the antibody, and blood thinners.

“Very, very few people will develop this complication,” Professor Andreas Greinacher said in a press conference Friday, according to the Wall Street Journal. “But if it happens, we now know how to treat the patients.”

Several European countries this week briefly halted use of the vaccine over fears of blood clots, which have been reported 37 times among the 17 million inoculated with the vaccine. The countries resumed use after the European Medicines Agency (EMA) determined the AstraZeneca vaccine was “safe and effective” and that the benefits outweigh the potential risks. Still, Norway, Sweden, Denmark and Finland have decided to keep the vaccine on hold until more research is done and public health experts worry the debacle will erode confidence in vaccines more generally.