Project S, an effectiveness study carried out by Butantan in the São Paulo municipality of Serrana, has transformed the course of vaccination campaigns since its inception, becoming a landmark in immunization against Covid-19 in Brazil and in the world. At that time, however, there was no idea of the consequences of the pandemic – nobody knew, for example, that six months after completing the vaccination schedule, a booster dose would be needed. With an estimated duration of one year, the project has generated many other researches, such as serological, which investigates the duration of immunity caused by the vaccine, and has produced extensive scientific data of international reference.
“Project S is like a big umbrella with several subprojects inside it, but from the point of view of the ethics committee, they are distinct projects”, says the director of the Serrana State Hospital, Marcos Borges. ""As it became a sentinel city, where the pandemic can be observed, other studies have emerged to assess immunity and the amount of antibodies produced by the vaccine at different ages.""
In its first stage, Project S vaccinated 27,000 residents with two doses of CoronaVac within a 28-day interval. The result was a drop of 80% of symptomatic cases and 95% of mortality. Immunization proved to be effective, even with around 10 thousand residents of Serrana working in the city of Ribeirão Preto, where there was a high number of cases in the same period.
The current phase of the research is evaluating the long-term immunity of the vaccinated, in a sufficient sample to represent the entire population. This stage comprises a prospective cohort study approved and monitored by the Ethics Committee for Research on Human Beings at the Hospital das Clínicas, at the Ribeirão Preto School of Medicine, University of São Paulo (USP). Through the study, immunization between adults and the elderly is being compared, taking into account the aging of the immune system.
This serological step aims to show how the organism reacts to vaccination. All volunteers will repeat blood tests every three months to measure the evolution of immunity over time. There is also a household survey that aims to estimate the incidence of SARS-CoV-2 in the population of Serrana and will be carried out once over a year.
The third booster dose began to be applied to elderly people in the region in September this year. “We didn't foresee the need for a third dose at the time Project S was designed. Later, in another phase, there will also be an analysis of these data”, says Marcos. He predicts that much more research will be generated in Serrana from Projeto S to assess the effects of the booster dose.
The first conclusions of the studies in Serrana have served as a reference for international immunization strategies and will be presented at the CoronaVac Symposium, of Instituto Butantan and Sinovac, between the 7th and 9th of September. On the first day of the international online event, researcher Marcos Borges will present the research methodology, values of direct and indirect effectiveness in the population of Serrana and serology data.