Antibodies are the only defence to prevent an infection, but their levels typically drop in the months after vaccination or recovery from the disease
A student receives a second dose of the Pfizer coronavirus vaccine at the Morris Heights Heath Center in the Bronx on Tuesday, July 27, 2021. The Pfizer-BioNTech vaccine’s effectiveness wanes slightly over time, according to newly released data from the companies, but remains strong in preventing severe disease. Image: James Estrin/The New York Times
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