SERRANA, Brazil: As Covid-19 has swept across Brazil, killing nearly a quarter of a million people, high infection rates have made the country the perfect testing ground for vaccines.
Now, Brazil is using its misfortune to help answer one of the most pressing questions of the pandemic, as millions are inoculated around the world: can someone vaccinated still transmit the virus?
In the first such experiment worldwide, researchers began a project on Wednesday to vaccinate the entire adult population of Serrana, a suburban city of 45,000 in the state of São Paulo before the rest of the country.
They say the results will help scientists around the world understand how quickly vaccines can slow the coronavirus pandemic. And vaccinating an entire city will counter Brazil’s growing vaccine movement and demonstrate the broader benefits of mass immunization, such as a rapid economic recovery expected with a rapid reopening of Serrana.
“It will provide us with information on the percentage of people who need to be vaccinated to achieve herd immunity, yet no one knows,” said Marcos Borges, a professor of medicine at the University of São Paulo, near Ribeirão Preto, who leads the study.