How a vaccination experiment known as 'Project S' transformed one small Brazilian city

Updated 1812 GMT (0212 HKT) June 6, 2021

Serrana (CNN)Hope has returned to the small city of Serrana, Brazil, after researchers vaccinated almost its entire adult population in a city-wide medical experiment this spring.

"Everything is practically open now, and the atmosphere is so different, so much lighter and joyful. We feel safe while the other cities around us are in a very difficult situation," says Ricardo Luiz, owner of a well-known restaurant in Serrana.
Four months after the kickoff of the experiment known as Project S, this quiet city surrounded by sugar plantations has acquired an atmosphere of pre-pandemic days, Luiz says.
His business is getting back on its feet after one year of hardship and it's currently bringing in 70% of the revenue it made before the pandemic.
"People feel safe to leave the house," he says, adding that he no longer feels afraid for his family or acquaintances traversing the city's hot and dry streets. "We know everyone here, and nowadays it's rare to hear about cases and deaths," he says.
Nationwide, Brazil has the second-highest number of deaths from Covid-19 in the world, after the US, and it is heading to its third wave with daily cases and deaths on the rise. Only 10% of Brazil´s population is fully vaccinated.
But people living in Serrana say they're experiencing a very different reality, thanks to Project S.
People in Serrana waiting to be vaccinated on February 25.
The project was coordinated by the biomedical center Butantan Institute in partnership with the Sao Paulo University of Medicine in Ribeirao Preto. This spring, researchers gave the full two doses of the vaccine Coronavac to 27,160 adults -- about 95% of the city's adult population. The Coronavac, designed by Chinese pharmaceutical Sinovac and produced in part in Brazil in partnership with Butantan, has shown a global efficacy of 50.8% in Phase III tests.
Researchers' full findings from Project S have not yet been peer-reviewed or published. However, according to preliminary results released on June 1, the study showed an 80% reduction in the number of symptomatic cases. Covid-related hospitalizations have fallen by 86% and mortality by 95% -- figures hailed by Sao Paulo Governor Joao Doria as a good omen for the rest of the country.
According to the study, the immunization generated a kind of "immune belt" in Serrana, drastically reducing the transmission of coronavirus in the municipality even as the virus raged throughout the country.