Immunity to Omicron Low for Children With Prior COVID-19 Infection

FRIDAY, June 3, 2022 (HealthDay News) -- For pediatric patients with prior COVID-19 or multisystem inflammatory syndrome in children (MIS-C), cross-reactive immunity against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) omicron variant is low, according to a study published online May 27 in Nature Communications.

Juanjie Tang, from the U.S. Food and Drug Administration in Silver Spring, Maryland, and colleagues examined virus-neutralizing capacity against the SARS-CoV-2 alpha, beta, gamma, delta, and omicron variants in 177 pediatric patients hospitalized with severe acute COVID-19 or acute MIS-C and in convalescent samples of outpatients with mild COVID-19 during 2020 and early 2021.

The researchers found that less than 10 percent of all patients showed neutralizing antibody titers against omicron. Lower neutralizing antibodies to SARS-CoV-2 variants were seen for children younger than 5 years of age versus those aged older than 5 years. Compared with hospitalized acute COVID-19 patients, convalescent pediatric COVID-19 and MIS-C cohorts had higher neutralization titers. Some loss of cross-neutralization was seen against all variants, with the most pronounced loss against omicron. Children receiving two doses of an mRNA COVID-19 vaccine had higher titers against the alpha, beta, gamma, delta, and omicron variants than those with previous SARS-CoV-2 infection.

"Our study highlights the importance of vaccinating children and younger adolescents even with preexisting antibody immunity by an earlier SARS-CoV-2 strain to prevent severe disease in children from Omicron and future infections," the authors write. "These findings have direct implications for developing age-targeted strategies for testing, disease mitigation, vaccination, and protecting this vulnerable population."

One author disclosed financial ties to the pharmaceutical industry.

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