Kids who had mild COVID still have antibodies months later

"The study shows that children who've had mild infections or even those who did not have any symptoms, develop an immune response that will likely provide some protection against future infections," says Jillian Hurst. (Credit: Rusty Watson/Unsplash)

Researchers have found robust antibody responses up to four months after infection in children and adolescents who had mild to asymptomatic cases of COVID-19.

The study found that the children and adolescents who previously had COVID-19 developed antibody responses capable of neutralizing the SARS-CoV-2 virus. Further, these responses were comparable or superior to those observed in adults.

“These findings are encouraging, especially because we cannot yet vaccinate children under the age of 12 against the virus,” says co-lead author Jillian Hurst, assistant professor in the pediatrics department at Duke University School of Medicine.

“The study shows that children who’ve had mild infections or even those who did not have any symptoms, develop an immune response that will likely provide some protection against future infections.”

The researchers evaluated the SARS-CoV-2-specific immune responses in 69 children and adolescents, with ages ranging from 2 months old to 21 years-old. The median age of participants was 11.5 years, and 51% were female.

The researchers measured antibody responses among children and adolescents with asymptomatic and mild symptomatic SARS-CoV-2 infection and found that the antibody response did not differ based on the presence of symptoms, and SARS-CoV-2 neutralizing antibodies remained detectable in the majority of participants up to four months after infection.

The researchers also compared the children’s immune responses to those of adults. They found that all children, regardless of age group, had equivalent or slightly higher levels of antibodies than adults at two months and four months after acute infection.

“Most studies of the immune responses of children to SARS-CoV-2 have focused on patients hospitalized for severe COVID-19 or multi-system inflammatory syndrome in children (MIS-C), or have assessed immunity only during acute infection,” Fouda says.

“Our study provides important information that SARS-CoV-2-specific immune responses, regardless of disease severity, may decline over time more slowly in children and adolescents.”

The findings suggest vaccinating young children against COVID-19 could also elicit a similar or greater degree of protection than that of adults, the study authors say.

The study of 69 children appears in JCI Insight.

The study received funding from the Duke University School of Medicine; the US Department of Veterans Affairs, Veterans Health Administration, Office of Research and Development; the National Institutes of Health; the US Defense Advanced Projects Agency; and Virology Quality Assurance. COVID-19 samples were processed at the Duke Regional Biocontainment Laboratory, which received partial support for construction from NIH.

Source: Duke University