(CNN) — Ten people with delta variant COVID-19 infections were reinfected with the omicron variant less than 90 days after their first infection, according to a new study from the US Centers for Disease Control and Prevention (CDC). , for its acronym in English).
The study, published Thursday in the CDC’s Morbidity and Mortality Weekly Report, identified five people from Vermont, three from Wisconsin, one from Washington and one from Rhode Island who had these early reinfections.
Since most PCR tests do not identify the specific variant of covid-19 responsible for an infection and some people may have viral RNA remaining after infection, the study used whole genome sequencing (WGS) of the virus to confirm. the variant.
The first cases of covid-19 reinfection, defined as any reinfection occurring within 90 days of a previous WGS-confirmed infection, occurred between October 2021 and January 2022. The shortest interval between reinfections was 23 days for the guy from Washington.
Eight of the 10 patients were under 18 years of age. One was a resident in a long-term facility and another was a health worker. Only one of the patients had received two doses of an mRNA vaccine before the first infection, and two people had received a single dose of an mRNA vaccine between infections. The other seven were not vaccinated.
Nine of the COVID-19 patients reported having symptoms during their first infection, and of the eight patients followed up, six had symptoms during their second infection.
While this study does not represent the general US population, “this study highlights the potential limits of infection-induced immunity against new variants,” the report states.