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Children infected with COVID-19 continue to have antibodies at least six months after infection, according to a new study.
However, experts caution they don’t know if the antibody levels are high enough to provide significant protection, especially against the omicron variant. Authors also noted many children haven’t been infected.
"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," corresponding author Sarah Messiah, Ph.D., M.P.H., said in a news release. "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."
The study is part of the Texas Coronavirus Antibody REsponse Survey and was conducted by researchers from University of Texas institutions. The findings were published today in in “Durability of SARS-CoV-2 Antibodies from Natural Infection in Children and Adolescents (Messiah SE, et al. Pediatrics. March 18, 2022).
Three times in a six- to eight-month period, 218 children ages 5-19 years were given tests that could detect antibodies to the SARS-CoV-2 nucleocapsid protein from past infection. Vaccination elicits antibodies to the spike protein, which is not detected by the test utilized in this study.
About 34.4% of participants had evidence of nucleocapsid antibodies at the start of the study. Nearly all children in that group continued to have detectable antibodies more than six months later. Researchers did not see differences based on age, sex or body mass. The presence or severity of symptoms also did not seem to play a role in the detection of antibodies.
“These results suggest that infection-induced antibodies persist and thus may provide some protection against future infection for at least half a year,” authors wrote.
However, authors of a related commentary noted experts don’t know what antibody levels are needed to protect against future infections. For children not eligible for vaccination or unvaccinated due to their parents’ hesitancy, the study “is somewhat reassuring,” they wrote, but “should not provide false reassurance.”
“Natural infection with coronaviruses confers only transient humoral immune response; in contrast, mRNA vaccines have less decay in antibody responses over time and may also result in cell-mediated immunity,” according to the commentary.
Authors of both the study and the commentary stressed the importance of vaccination to protect them.
About 58% of 12- to 17-year-olds and 27% of children ages 5-11 are fully vaccinated, according to Centers for Disease Control and Prevention data. Nearly 12.8 million children have tested positive for COVID-19 since the onset of the pandemic, data from the AAP and Children’s Hospital Association show.