Children can have COVID-19 virus and antibodies in system at same time, research finds
With many questions remaining around how children spread COVID-19, Children's National Hospital researchers set out to improve the understanding of how long it takes pediatric patients with the virus to clear it from their systems, and at what point they start to make antibodies that work against COVID-19.
The study used a retrospective analysis of 6,369 children tested for SARS-CoV-2, the virus that causes COVID-19, and 215 patients who underwent antibody testing between March 13and June 21. Out of the 215 patients, 33 had co-testing for both the virus and antibodies during their disease course. Nine of the 33 showed presence of antibodies in their blood while also later testing positive for the virus, according to the study.
The study also assessed the timing of viral clearance and immunologic response. It found the median time from viral positivity to negativity, when the virus can no longer be detected, was 25 days. The median time to seropositivity, or the presence of antibodies in the blood, was 18 days, while the median time to reach adequate levels of neutralizing antibodies was 36 days. Neutralizing antibodies are important in potentially protecting a person from re-infection of the same virus.
Additionally, the researchers found patients 6 through 15 years old took a longer time to clear the virus compared to patients 16 through 22 years old, with a median of 32 days versus a median of 18 days, respectively. Females in the same age group also took longer to clear the virus than males, with a median of 44 days for females compared to median of 25.5 days for males.
The researchers said the next phase of research will be to test if the virus that is present alongside the antibodies can be transmitted to other people. It also remains unknown if antibodies correlate with immunity, and how long antibodies and potential protection from reinfection last.
“The takeaway here is that we can't let our guard down just because a child has antibodies or is no longer showing symptoms," said Burak Bahar, MD, lead author of the study and director of laboratory informatics at Children's National Hospital, in a statement. “The continued role of good hygiene and social distancing remains critical.”