The Butantan Institute announced at a press conference today that the Coronavac vaccine has an overall efficacy of 50,38% against Covid-19, above the rate required by the World Health Organization (WHO) for an immunizer to be considered viable.

As Ricardo Palacios, medical director of Butantan, explained, the research developed by the Institute to certify the vaccine’s efficacy also included those asymptomatic cases, of volunteers who did not need medical assistance, which impacts on the percentage of efficacy – but not on the performance of the immunizer. The vaccine’s efficacy in mild cases is 78%; and in moderate and severe cases, is 100%, according to the research.

Palácios assured that Coronavac is sufficiently effective to reduce the number of severe cases in situations of high exposure to the virus, avoiding the need for hospital care. Regarding the effect of the vaccine on the transmission of the new coronavirus, the scientist said that is necessary a new study for evaluation.

During the research by Butantan, 218 people were infected, 160 of whom received a placebo and 60 received the vaccine. The research, as detailed in the press conference, did not assess the number of asymptomatic volunteers. In the testing phase, Coronavac was applied in a group of 12.508 volunteers, all of whom were healthcare professionals over 18 years old.

Now, it is up to Anvisa, Brazilian Health Regulator, to analyze the request for emergency use of Coronavac in Brazil.