A Brazilian study carried out by researchers at the Escola Paulista de Medicina, at the Federal University of São Paulo (Unifesp) shows that a booster dose of the Pfizer vaccine increases the level of antibodies by up to 25 times after two applications of CoronaVac. Protection grows sevenfold when starting doses are from AstraZeneca. The research results were published in the scientific journal Journal of Infection.
The study was carried out with a group of 48 health professionals from hospitals and regional institutions, with a mean age of 30 years for those vaccinated with Coronavac and 40 years for those who received AstraZeneca.
“We have seen that adherence to the booster dose of the Covid-19 vaccine is not as high as it could be. Our study, however, shows the importance of the population taking the third dose because there is a significant increase in the immune and cellular response, indicating greater levels of protection” said Alexandre Keiji Tashima, professor at the Department of Biochemistry at Unifesp and author of the article.
As of 10 am this Tuesday (8), at least 396,392,423 doses of vaccines against Covid-19 had been applied in Brazil. The information is from CNN Brasil based on the state secretariats that released the preliminary assessment of vaccination.
According to the survey, 155,761,793 people have already received the second dose of the vaccine or received the Janssen single-dose vaccine and are therefore fully immunized. In all, 66,633,232 people received the 3rd dose or booster.
“With the pandemic, we set up a group of researchers at Unifesp to work on studies involving Covid-19. The objective is to carry out a complete biochemical characterization of the antibodies”, says Tashima, who is the doctoral supervisor of Jackelinne Yuka Hayashi, first author of the article.
The work, supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (Fapesp), also had the participation of four researchers from Euroimmun Brasil, a company specializing in solutions for laboratory diagnosis.
The group’s results corroborate studies already published by scientists from Hong Kong and from North American universities.
In addition, other research had shown the effectiveness of the booster dose. One of them, published in early February in Nature Medicine, showed that the application of the third dose of Pfizer vaccine six months after immunization with two of Coronavac confers an efficacy of 92.7% against the disease. Protection against severe cases rises to 97.3%. Data from about 14 million Brazilians were analyzed.