SERRANA, Brazil – As Covid-19 spread across Brazil, killing nearly a quarter of a million people, high infection rates have turned the country into a perfect testing ground for vaccines.
Now, Brazil is using its misfortune to help answer one of the most urgent questions in the pandemic, while millions are being inoculated worldwide: Can someone who has been vaccinated still transmit the virus?
In the first experiment of its kind on a global level, the researchers started a project on Wednesday to vaccinate the entire adult population of Serrana, a city of 45,000 inhabitants 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 contain the coronavirus pandemic. And vaccinating an entire city will counteract the growing antivax movement in Brazil and demonstrate the wider benefits of mass immunization, such as the rapid economic recovery expected with the rapid reopening of Serrana.
“This will give us information about the percentage of people who need to be vaccinated to achieve herd immunity – no one knows that yet,” said Marcos Borges, a professor of medicine at the University of São Paulo in nearby Ribeirão Preto who is leading the study.