Brazilian town experiment shows mass vaccination can wipe out COVID-19

A small commuter town surrounded by sugarcane fields in southeastern Brazil, one of the countries hardest hit by COVID-19, has shown that even a vaccine that had low efficacy in some clinical trials can dramatically control the pandemic virus.

As part of an unusual experiment to track the real-world effectiveness of CoronaVac, a COVID-19 vaccine made by a Chinese company, almost all adult residents of Serrana, in the state of São Paulo, received the required two shots between February and April, long before most would otherwise have become eligible for the vaccine. The results were dramatic. Symptomatic cases of COVID-19 have dropped by 80% since the start of mass vaccination, related hospitalizations fell 86%, and deaths plummeted 95%, the research team in charge of the experiment reported during a press conference yesterday.

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