Washington: People who have recovered from Covid-19 only need one dose of vaccine. A second shot is important for those who haven’t had Covid-19 to achieve strong immunity, one study suggests.
The study, led by researchers at the University of Pennsylvania in the US, found that Covid survivors had a robust antibody response after the first dose of mRNA vaccine, but little immune benefit was seen after the second dose.
On the other hand, those who did not have Covid-19 – termed Covid naive – did not have a full immune response until after receiving their second vaccine dose, underscoring the importance of completing the two recommended doses for achieving strong immunity levels. .
Two doses are optimal to elicit strong antibody and B cell responses in patients immunologically naïve to SARS-CoV-2 and antibodies induced by vaccination could protect against the more contagious and lethal South African variant , the researchers said.
The findings, published in the journal Science Immunology, provide further insight into the underlying immunobiology of mRNA vaccines, which may help shape future vaccine strategies.
“These results are encouraging for both the short-term and long-term efficacy of vaccines and contribute to our understanding of the mRNA vaccine’s immune response through the analysis of memory B cells,” said John E Wherry , director of the Penn Institute of Immunology.
The human immune response to vaccines and infections results in two important results: the production of antibodies that provide rapid immunity and the formation of memory B cells, which aid in long-term immunity.
For the study, the team included 44 healthy individuals who received the BioNTech / Pfizer or Moderna mRNA Covid-19 vaccine. Of this cohort, 11 had a previous Covid-19 infection. Blood samples were collected for deep immune assays four times before and after vaccination doses.
They confirmed that the mRNA vaccines induced antibodies that could neutralize the D614C and B1351 variants. These responses peaked one week after the second vaccine dose in naive patients, but peaked two weeks after the first dose in recovered patients, with similar patterns in B cell responses for both groups.
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