A large number of US adults may have been infected with SARS-CoV-2 and never knew, according to new data from the Center for Disease Control and Prevention.
Investigators studied blood serum in a sample of US adults between August 2021 and May 2022 in a quest to discover who had antibodies to the virus. Fully 42% of participants had signs of prior infection or vaccination, they found. Among this group, approximately 44% were “possibly asymptomatically infected,” they reported.
The study also uncovered distinctive patterns. Signs of vaccination without infection were lower among adults who were younger, Hispanic, non-Hispanic Black or African American, and those who had relatively lower education levels. Among those whose blood samples had signs of infection and/or vaccination, a higher percentage of younger and Black adults did not report being vaccinated. This finding suggests that many in those groups acquired their antibodies through infection rather than through vaccination, the investigators wrote.
In addition, the evidence reflect higher vaccination rates among older adults and higher infection rates among younger people, confirming the results of similar studies.
“CDC recommends that everyone stay up to date with COVID-19 vaccination,” the investigators concluded. “These results can guide ongoing efforts that are needed to achieve equity in primary series vaccination and booster dose coverage.”
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