The Coronavac, applied in 27,1 thousand residents of the municipality, localized in the region of Ribeirão Preto protected vaccinated and non vaccinated, creating a collective “immunological belt” against the virus, reducing drastically its transmission, as revealed by the unprecedented study in the world. 

The immunization of all the adult population of the municipality of Serrana, in the countryside of São Paulo, with the Butantan´s CoronaVac caused a great reduction of 80% of the symptomatic cases and 95% of deaths after the second vaccination of the last group of the city (please see the trust gap in the end of the text). 

This is the main conclusion of the clinical study of effectiveness - named “Project S” - an unprecedented study in the world, coordinated by the Institute that is related to the Government of São Paulo. 

The reduction was stated by the comparison of the data from the beginning of the project until the vaccination of all the groups was completed - with all the trimester evaluated (february, march and april of 2021). 

The results also showed that the vaccination protects not only the adults that received the two doses of the immunization but also the children and teenagers with less than 18 years old who were not vaccinated. 

This proves that the intervention made in the city by Butantan created in it a true “immunological belt” with a collective barrier against the virus, drastically reducing the transmission in the municipality. 

Another important conclusion of the research is the incidence of the disease in Serrana in comparison with the nearby cities. Serrana has around 10 thousand residents that works  in Ribeirão Preto daily. However, while Ribeirão Preto and others cities in the region are presenting high levels of COVID-19 cases, Serrana maintained low taxes if compared to the cities with similar profile, due to the vaccination. 

In other words, the success of the vaccination was confirmed not only by the decrease in the number of infected people but also showed that the residents of Serrana that goes daily from one city to another did not bring a relevant increase in the number of cases. 

Between February 17 and April of this year, during 8 weeks, around 27 thousand residents of the municipality received the completed vaccination scheme: two doses of the Coronavac with a gap of 28 days between the first and second doses. This represents a coverage of approximately 95% of the adult population of residents, according to the health census made previously by Butantan. 

The research, conducted by Butantan Institute and approved by the ethical and sanitary authorities, co