People over 55 who have been vaccinated with CoronaVac may need a third dose of Covid-19. According to a study carried out by the Instituto do Coração (InCor) and the Faculty of Medicine of the University of São Paulo (USP), which has not yet been reviewed by peers, these individuals can benefit from taking the booster of some other vaccine.
101 people fully vaccinated with CoronaVac participated in the study, of which 42 were over 60 years old; 72 people who recovered from the disease and 36 who made up the control group, not having been vaccinated or infected.
The results indicate that after a certain age, the protection induced by the Butantan vaccine is not so superior to the protection acquired after exposure to the new coronavirus.
According to the study, 95% of those vaccinated had T cells, which are responsible for eliminating infected cells, or antibodies against the coronavirus. Among infected and recovered individuals, this percentage rose to 99%.
As for the rate of anti-spake antibody, a protein used by the virus to enter cells, it was also higher among those recovered, being 6 times higher in people recovered from the disease aged 55+ than in those vaccinated.
Therefore, the researchers suggest that people over 55 who are immunized with CoronaVac may benefit from the third dose of a different vaccine. “Given the finding that mixing vaccines with different platforms produces stronger immune responses, our results may suggest that CoronaVac vaccinated over 55 years may benefit from a different third dose/boost vaccine,” the authors state, according to the G1.
It is worth remembering that, although the rate of protection declines after the age of 55, all people who participated in the study had some level of protection against Covid-19. The immune response in this age group of those vaccinated against Covid-19 was 94% in women and 83% in men.