HealthDay News — From December 2021 to February 2022, the seroprevalence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) increased, reaching about 75% among children and adolescents by February 2022, according to research published in the April 26 early-release issue of the US Centers for Disease Control and Prevention Morbidity and Mortality Weekly Report.
Kristie E. N. Clarke, MD, from the CDC COVID-19 Emergency Response Team, and colleagues examined US trends in infection-induced SARS-CoV-2 seroprevalence during September 2021 to February 2022. A convenience sample of blood specimens submitted for clinical testing was analyzed for anti-nucleocapsid antibodies every 4 weeks during the study period; in February 2022, the sampling period was under 2 weeks in 18 of the 52 jurisdictions.
The researchers found that per 4-week period, there was an increase of 0.9 to 1.9 percentage points in the overall seroprevalence during September to December 2021, followed by an increase in overall US seroprevalence from 33.5 to 57.7% during December 2021 to February 2022. During the same period, seroprevalence increased from 44.2 to 75.2% and from 45.6 to 74.2% among children aged 0 to 11 years and aged 12 to 17 years, respectively. Among adults aged 18 to 49 years, seroprevalence increased from 36.5 to 63.7%, while among those aged 50 to 64 years and aged 65 years and older, seroprevalence increased from 28.8 to 49.8% and from 19.1 to 33.2%, respectively.
“These findings illustrate a high infection rate for the omicron variant, especially among children,” the authors write.