Research based on the Boston Children’s Hospital-led Overcoming COVID-19 National Study and the hospital’s Taking On COVID-19 Together Group provides evidence that children previously infected with COVID-19 (or the inflammatory disease MIS- C) were ill are not protected against the newer Omicron variant.

However, vaccinations offer protection, according to the study. The results, published in nature communication on May 27 parallel similar findings in adults.

“I hear parents say, ‘Oh, my kid had COVID last year,'” says Adrienne Randolph, MD, MSc, of Boston Children’s Hospital, which launched Overcoming COVID-19 in 2020. Randolph was senior author of the current article with Surender Khurana, PhD, from the Food and Drug Administration’s Division of Viral Products, Center for Biologics Evaluation and Research. “But we found that antibodies produced by previous infections in children, Omicron did not neutralize, meaning unvaccinated children remain susceptible to Omicron.”

Researchers obtained blood samples from 62 children and adolescents hospitalized with severe COVID-19, 65 children and adolescents hospitalized with MIS-C, and 50 outpatients who had recovered from mild COVID-19 . All samples were taken in 2020 and early 2021 before the Omicron variant emerged.

In the lab, they exposed the samples to a pseudovirus (derived from SARS-CoV-2 but stripped of its virulence) and measured how well antibodies in the samples were able to neutralize five different SARS-CoV-2 variants: alpha , beta, gamma, delta and omicron.

Overall, children and adolescents showed some loss of antibody cross-neutralization against all five variants, but the loss was most pronounced with Omicron.

Omicron is very different from previous variants, with many mutations on the spike protein, and this work confirms that it is able to evade the antibody response. Unvaccinated children remain vulnerable.”

Adrienne Randolph, MD, MSc, Boston Children’s Hospital

In contrast, children who received two doses of the COVID-19 vaccine showed higher neutralizing antibody titers against the five variants, including Omicron.

Randolph hopes this data will encourage parents to vaccinate their children and adolescents. According to the CDC, as of May 18, 2022, only 28 percent of 5- to 11-year-olds and just 58 percent of 12- to 17-year-olds had received two doses of the vaccine, numbers that have changed little since March. An FDA panel will meet on June 15 to review approval of COVID-19 vaccines for children under the age of 5.


Boston Children’s Hospital

Magazine reference:

Tang, J. et al. (2022) Cross-reactive immunity to the SARS-CoV-2 omicron variant is low in pediatric patients with prior COVID-19 or MIS-C. nature communication.

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