The booster dose of the Coronavac vaccine against Covid-19 increases by about 20 times the level of neutralizing antibodies, which are those capable of fighting infection by all strains of the new coronavirus, including the Ômicron variant.
The information was given this Wednesday (8) by scientist Xiangxi Wang, a researcher at the Laboratory of Infection and Immunity at the Institute of Biophysics of the Chinese Academy of Sciences, during a symposium promoted by the Butantan Institute in partnership with the pharmaceutical company Sinovac.
Several scientific studies have shown that six months after the second dose of the different Covid-19 vaccines, the production of this type of antibody drops. Therefore, laboratories indicated the need for a booster dose as a mechanism to increase protection against severe cases of the disease.
According to the researcher, mutations present in the Spike protein – used by the virus to invade human cells, can promote resistance to vaccines. “A plausible alternative to resolve this issue is to administer the third dose of vaccine between six and 12 months after the second dose, to improve and extend protection,” said the researcher in a statement.
According to Wang, analyzes carried out in the laboratory with the plasma of individuals who received the third dose of Coronavac proved that the immunizing agent is capable of recovering the production of neutralizing antibodies.
The recorded increases in antibody levels were 17-fold against the Delta variant and the original (Wuhan’s) coronavirus strain, 18-fold against the Alpha variant, 19-fold against the Beta strain, and 14-fold against the variant Gamma.
According to the researcher from the Chinese Academy of Sciences, the neutralizing antibody titration was maintained after six months after the application of the booster dose.
Vaccines can be developed using different technologies, but the ultimate goal is the same: to provide the immune system with the information it needs to activate the various defense mechanisms against a harmful microorganism.
In the immune response, in addition to the production of antibodies, there is an essential function for the body’s defense, which is the activation of other cells, called T lymphocytes. Together, these cells respond against infection, mainly preventing severe cases, hospitalizations and deaths from the disease.
Scientists are constantly studying these immune response induction mechanisms in order to understand the possible impacts of new variants on the effectiveness of vaccines.
Researcher Xiangxi Wang performed the analysis of more than 200 structures of the coronavirus and investigated the binding sites (or sites) of six types of neutralizing antibodies. According to the analysis, the first three antibodies, predominant at the start of immunization, were not able to recognize the variants.
The study showed three other types of antibodies that recognize Spike protein structures and show high neutralizing capacity against variants, including micron. “These antibodies are significantly increased after the third dose. Thus, the additional sweetness leads to a durable and quick recovery of humoral immunity,” said Wang.
Reference: CNN Brasil
