Natural circulating antibodies last for at least seven months in children infected with COVID-19

Children previously infected with COVID-19 develop natural circulating antibodies that last for at least seven months, according to a new study led by researchers at UTHealth Houston.

The study was published today in Pediatrics.

Researchers examined data from 218 children across the state of Texas between the ages of 5 and 19 who were enrolled in the Texas CARES survey, which began in October of 2020 with the goal of assessing COVID-19 antibody status over time among a population of adults and children in Texas.

Volunteers who enrolled in the study provided researchers with three separate blood draws. Samples were collected before the vaccine rollout and during the Delta and Omicron variants. To date, investigators have completed three different phases of the study.

This is the first study from the Texas CARES survey that includes data from all three time points in the survey. These findings are important because the information we collected from children infected with COVID-19 didn't differ at all by whether a child was asymptomatic, severity of symptoms, when they had the virus, were at a healthy weight or had obesity, or by gender. It was the same for everyone."

Sarah Messiah, PhD, MPH, corresponding author of the study and professor of epidemiology, human genetics, and environmental sciences at UTHealth School of Public Health Dallas campus

While 96% of those infected with COVID-19 continued to have antibodies up to seven months later, well over half (58%) of the sample were negative for infection-induced antibodies at their third and final measurement. The findings do not include the impact of vaccine protection.

The results of Texas CARES, Messiah said, are just a step in understanding the virus's impact on children. To date, 14 million kids in the U.S. have tested positive for the virus, she said.

"Adult literature shows us that natural infection, plus the vaccine-induced protection, gives you the best defense against COVID-19. There has been a misunderstanding from some parents who think just because their child has had COVID-19, they are now protected and don't need to get the vaccine. While our study is encouraging in that some amount natural antibodies last at least six months in children, we still don't know the absolute protection threshold. We have a great tool available to give children additional protection by getting their vaccine, so if your child is eligible, take advantage of it," Messiah said.