A study shows that antibodies produced by a person previously infected with the coronavirus do not appear to be able to block the Brazilian variant.
Scientists from the University of Sao Paulo (USP) and the University of Campinas (Unicamp) reported that the Brazilian strain called P.1 could escape the antibodies generated by the Coronavac vaccine.
The researchers collected plasma from eight volunteers who participated in clinical trials and used the samples to test the effectiveness of the vaccine with the strain detected in Manaus city, Amazonas state, earlier this year.
The results of the research were published by the journal The Lancet in its section of articles not yet peer-reviewed.
In addition to pointing out that research with larger samples is needed to confirm their findings, the researchers explained that other factors could influence the results obtained. Among them is the role those other elements of the immune system such as "memory lymphocytes" play in severe COVID-19 cases.
In this regard, they believe that a third booster dose of the modified vaccine for the Brazilian variant may be necessary to stop the spread of the new strain throughout the country.
The USP-Unicamp study also shows that antibodies produced by a person previously infected with the coronavirus do not appear to be able to block the Brazilian variant.
"Thus, reinfection may be plausible with variants with mutations in the 'spike' protein," the researchers said and explained that this protein is the element used by the coronavirus to penetrate human cells.
In the past week, two scientific studies have also indicated that P.1 may have a viral load up to ten times higher. This would make it a more transmissible variant and capable of evading the immune system of those who already had antibodies.
So far, authorities have reported the presence of the Brazilian strain in 17 out of 27 states.