What is the risk of BA.5 infection in people with documented infection with earlier variants?

A recent correspondence published in The New England Journal of Medicine

Study : Risk of BA.5 infection in people exposed to previous SARS-CoV-2 variants. Crédit image : DarkClearSky/Shutterstock

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About the study

National SARS-CoV-2 genetic surveillance in Portugal was used to determine periods of major variant dominance, during which variants were present in more than 90% of samples. Individuals who acquired a first infection during the period of dominance of each variant were identified from the registry. Figures were pooled for BA.1 and BA.2 infections due to the slow transition between their periods of dominance.

The study population also had over 98% vaccination coverage, including Comirnaty (Pfizer/BioNTech), Spikevax (Moderna), Vaxzevria (AstraZeneca), and Janssen vaccines. Coverage of the first booster before June 1, 2022 was over 82%, and only mRNA vaccines (Comirnaty and Spikevax) were used.

Results

Conclusions