Deaths from COVID-19 in the city of Serrana, in the interior of the state of Sao Paulo, fell by 95% after the vaccination of almost all adults with CoronaVac, the vaccine from the Chinese company Sinovac Biotech, was completed, according to a study published Monday.
The coronavirus pandemic can be controlled if 75% of the population is vaccinated against COVID-19, according to a study carried out in a Brazilian city, where its inhabitants were massively immunized with the vaccine from the Chinese laboratory Sinovac, the Institute reported on Monday. Butantan.
According to the study, the first of its kind to be carried out worldwide, deaths fell by 95% after mass vaccination, hospitalizations fell by 86% and symptomatic cases were reduced by 80%.
The results reinforced calls to immunize most of the population to control the pandemic.
With a population of 45,000, Serrana has become an oasis in Brazil, a country that has the second deadliest COVID outbreak in the world, with more than 462,000 deaths and a slow rate of immunization due to a shortage of vaccines.
Butantan, which produces the CoronaVac vaccine from Sinovac, began research in February with the aim of vaccinating the entire adult population of the city (about 30,000 people) to assess the impact of mass immunization in the fight against the COVID-pandemic. 19.
Serrana was chosen for the study because it is a city with a low population with high rates of contagion by COVID-19.
The vaccination process of the so-called ‘Project S’ (Serrana Project) lasted four weeks and in each one of them a group of adults was immunized. At the beginning of the vaccination, the city was facing an increase in COVID cases, but the spread of the virus was contained after 75% of the population was immunized, according to the research.
Those responsible for the study compared the data from the beginning of the project – until the vaccination of all groups was completed – with the rest of the evaluated quarter (February, March and April 2021).
The data indicate that on February 16, one day before the massive vaccination process began, this municipality had 57 deaths and 2,499 confirmed cases of the virus.
After immunization, cases fell to 699 in March and 251 in April. Deaths plummeted from 30 to 6 in the same period.
The results also showed that vaccination protects both adults who received the two doses of the Chinese immunizer and children and adolescents under 18 years of age, who were not vaccinated.
As explained by the director of clinical trials of the Butantan Institute, the Colombian Ricardo Palacios, also director of the study, the immunization generated a kind of “immune belt” in Serrana, “drastically reducing” the transmission of the virus in the municipality.
“The most important result was to understand that we can control the pandemic even without vaccinating the entire population. When coverage of 70% to 75% was reached, the fall in incidence was noticed even in the last group that had not yet completed the vaccination schedule, “he said. “It will not be necessary to vaccinate minors,” he said.
The number of symptomatic cases was reduced by 80% and hospitalizations by 86%, in addition to a 95% reduction in deaths, according to data from Butantan. The results of the investigation had been anticipated on Sunday by TV Globo.
According to Butantan, vaccination in Serrana was carried out with the P.1 variant as the predominant one, which reinforced the efficacy against the coronavirus strain originating in Manaus, which became the main one in the country since the beginning of the year.
The Butantan researchers also claimed that the vaccination did not generate any genetic selection for new coronavirus variants, which was a concern in the mass vaccination process.
Serrana is surrounded by cities that continue to face an increase in COVID cases. Ribeirão Preto, 25 kilometers away, is currently under strict quarantine to try to contain the spread of COVID-19.
For the director of the Butantan Institute, Dimas Covas, this shows that the Sinovac vaccine “is safe, effective and efficient” and contributes to preventing the development of the disease, complications and deaths among those infected.
“We now also know that it has a beneficial effect on the entire population, protecting both vaccinated and unvaccinated people and significantly reducing viral circulation,” he added.
With information from EFE and Reuters
