Infants and children who have experienced Sars-CoV-2 infection “have significantly higher levels of antibodies” against the virus than adults. This is what emerges from a study conducted by scientists from the Johns Hopkins University Bloomberg School of Public Health, in collaboration with the American Cdc (Centers for Disease Control and Prevention). The results of the new research, published online in the journal ‘Jci Insight’, differ from previous surveys which instead reported low responses in children exposed to Covid. In contrast, the work in question suggests that babies tend to have “strong antibody responses” after becoming infected with the pandemic coronavirus.
The analysis is based on samples taken from 682 children and adults from 175 Maryland families who participated in a surveillance study on the infection in home settings and who had not yet received an anti-Covid vaccine at that time. Participants ranged in age from 0 to 62 and samples were collected between November 2020 and March 2021. Researchers found evidence of anti-Sars-CoV-2 antibodies, indicating previous infection with the virus, in 56 people from 22 families. Of these, 15 were children between the ages of 0 and 4, and the youngest a 3-month-old baby. Another 13 were children between the ages of 5 and 17, and 28 were adults over 18.
Antibodies to a key site of the virus’ spike protein, the ‘receptor binding domain’ (Rbd), were present at much higher levels in children than in adults: more than 13 times higher in children aged 0. and 4 years and almost 9 times higher in 5-17 year olds. AND Levels of neutralizing Sars-CoV-2 antibodies, which can help predict protection against severe Covid, were nearly double in 0-4 year olds compared to adults. In most nuclei where both young and old had antibodies, 0-4 year olds had the highest levels of Sars-CoV-2 Rbd antibodies and neutralizing antibodies among all family members.
“This study shows that even children in their first years of life have the ability to develop strong antibody responses” to this infection, responses that “in some cases outweigh the responses of adults,” says Ruth Karron, principal investigator and director of Johns Hopkins. Vaccine Initiative at Bloomberg School.
Karron and colleagues set up their prospective home surveillance study (Search-Sars-CoV-2 Epidemiology And Response in Children) to learn more about infection in the relatively under-studied population under 5. None of the people analyzed were hospitalized for Covid. “These results – concludes Karron – should provide some reassurance that with the appropriate vaccine doses we can effectively immunize very young children against Sars-CoV-2”.
Karron and colleagues are continuing to analyze the follow-up samples of the protagonists of the analysis and of those who became infected during the Search study, to understand more about the quality of the antibody responses and to see how long they are. The study was funded by the CDC.