Home / Science / Health /  ‘Booster doses may be effective against multiple variants’
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NEW DELHI : New research showed that a combination of vaccination and naturally acquired infection appears to boost the production of antibodies against the coronavirus.

Scientists said the findings point to the possibility that vaccine booster doses may be equally effective in improving antibodies’ ability to target multiple variants of the virus, including the delta variant, which is now the predominant strain, and the recently detected omicron variant.

The study by the University of California, Los Angeles (UCLA) and published in the peer-reviewed journal mBio was done before the emergence of delta and omicron strains of the virus. However, Otto Yang, senior author of the study, said the results could apply to those and other new variants.

“The main message from our research is that someone who has had covid-19 and then gets vaccinated develops not only a boost in antibody amount but also improved antibody quality — enhancing the ability of antibodies to act against variants," said Yang.

“This suggests that having repeated exposures to the spike protein allows the immune system to continue improving the antibodies if someone had covid-19 and then been vaccinated," Yang said.

Yang, however, said it is not yet known whether the same benefits would be realized for people who have repeated vaccinations but who have not contracted covid-19.

The researchers compared blood antibodies in 15 vaccinated people who had not been previously infected with SARS-CoV-2, the virus that causes covid-19, with infection-induced antibodies in 10 people who were recently infected with SARS-CoV-2 but not yet vaccinated.

Several months later, the 10 participants in the latter group were vaccinated, and the researchers then re-analyzed their antibodies. Most people in both the groups had received the Pfizer–BioNTech or Moderna two-dose vaccines.

The scientists evaluated how antibodies acted against a panel of spike proteins with various common mutations in the receptor-binding domain, the target for antibodies that help neutralize the virus by blocking it from binding to cells.

They found that the receptor-binding domain mutations reduced the potency of antibodies acquired both by either natural infection or vaccination alone to about the same degree in both groups of people. However, when previously infected people were vaccinated about a year after natural infection, their antibodies’ potency was maximized to the point that they recognized all of the covid-19 variants the scientists tested.

“Overall, our findings raise the possibility that resistance of SARS-CoV-2 variants to antibodies can be overcome by driving further maturation through continued antigenic exposure by vaccination, even if the vaccine does not deliver variant sequences," the researchers said in the study.

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