Virus World

Children are almost as likely as adults to become infected with coronavirus, but they are less likely to have symptoms, according to a new study published Friday.  The new study, published in the journal JAMA Pediatrics, found adults and children living in Utah and New York City shared similar risks of becoming infected with coronavirus. But kids only had symptoms about half the time. "The study demonstrates that all along, children of all ages including infants and toddlers have had a similar risk of SARS- CoV-2 infection compared with adults," Dr. Flor Munoz, a pediatric infectious disease specialist at Texas Children's Hospital and associate professor of pediatrics at Baylor College of Medicine, wrote in an accompanying editorial. SARS-CoV-2 is the name of the coronavirus that causes Covid-19.  "The fact that children, and especially young children, can transmit SARS-CoV-2 is now established and more clearly understood," wrote Munoz, who was not involved in the study. She added that the new findings should be considered in pandemic control efforts as well as vaccine and therapeutics research.

These findings were published just a day after the companies Pfizer and BioNTech officially requested emergency use authorization from the US Food and Drug Administration for their Covid-19 vaccine, at a smaller dosage, in children ages 5 to 11.  The new research, conducted from September 2020 through April 2021, included data on 1,236 people from 310 different households with one or more children in New York City, and certain counties throughout Utah. Dr. Fatimah Dawood of the US Centers for Disease Control and Prevention and colleagues took a close look at the incidence of Covid-19 and found that among households with one or more people infected, the mean infection risk within those households was 52%, adding to the evidence that households remain a common place that the virus spreads.

Original findings published in JAMA Pediatrics (Oct. 8, 2021):

https://jamanetwork.com/journals/jamapediatrics/fullarticle/2785007 

Globally, the COVID-19 pandemic has had extreme consequences for the healthcare system and calls for diagnostic tools to monitor and understand the transmission, pathogenesis and epidemiology, as well as to evaluate future vaccination strategies.

Here we have developed novel flexible ELISA-based assays for specific detection of SARS-CoV-2 antibodies against the receptor-binding domain (RBD): An antigen sandwich-ELISA relevant for large population screening and three isotype-specific assays for in-depth diagnostics. Their performance was evaluated in a cohort of 350 convalescent participants with previous COVID-19 infection, ranging from asymptomatic to critical cases. We mapped the antibody responses to different areas on protein N and S and showed that the IgM, A and G antibody responses against RBD are significantly correlated to the disease severity. These assays-and the data generated from them-are highly relevant for diagnostics and prognostics and contribute to the understanding of long-term COVID-19 immunity.

Magnitude of SARS-CoV-2 virus exposure may contribute to symptom severity. In a sample of seropositive adults (n=1101), we found that individuals who lived with a known COVID-19 case exhibited greater symptom severity and IgG concentrations compared to individuals who were seropositive but did not live with a known case (P<0.0001).

Notably, working in close proximity to others, which has received substantial attention as a risk factor for COVID-19,20 did not exhibit statistically significant associations with symptom severity or IgG antibody concentrations. Our results suggest that high virus exposure levels, which may often occur when exposed to a cohabitant with COVID-19, contribute to greater disease severity and stronger antibody responses. Regardless of which individual in the household was exposed first, our results suggest that preventing transmission within households should be a critical area of focus for public health efforts designed to reduce rates of symptomatic COVID-19. Policies and interventions that apply only to public places (e.g., mask mandates, business capacity limits) may be insufficient unless they are combined with measures that also reduce transmission within households (e.g., intensive testing, contact tracing, and isolation programs).

Preprint available in merRxiv (March 12, 2021):

https://doi.org/10.1101/2021.03.11.21253421