NEW YORK: As new strains appear, updated Covid booster doses will be crucial for boosting population immunity, sugest a study.
The answer, according to researchers at the Washington University School of Medicine in St. Louis, is to choose a booster variety that is so distinct from the original strain of the virus that it causes the maturation of new and varied antibody-producing cells.
The risk of a serious illness and death was decreased by more than 90% with the first Covid vaccinations. Nonetheless, the virus later evolved. Breakthrough infections resulted from the antibodies' reduced ability to recognise and neutralise new variations, which had been so successful against the original strain.
The obvious solution was to update the vaccines to target new variants, but Ali Ellebedy, associate professor of pathology and immunology, medicine, and molecular microbiology at the university, explained that due to the initial vaccines' success against the original strain, designing an efficient variant booster shot proved challenging.
The team's research, which was published in the journal Nature, demonstrated that it is feasible to create a variant-specific booster that not only boosts existing antibodies but also prompts the production of new ones.
As a result, Ellebedy explained, "regularly administering boosters that target new variants would allow population-level protection to be maintained even while the virus changes."
The goal of developing boosters against new variants is to train the immune system to recognise characteristics that set the new variants apart from the original strain.
"Yet, the new variants still have many characteristics in common with the original strain, and it's feasible that the reaction to these similarities may outweigh the reaction to the new features. Instead of producing new memory cells, which is what we need for defence against new variations, the boosters may merely end up activating already-existing immunological memory cells, he said.
The researchers examined 39 individuals who had received the two-shot primary sequence of the Pfizer/BioNTech or Moderna Covid-19 vaccines, followed by an experimental booster shot that targeted the Beta and Delta variants, in order to evaluate the efficacy of boosters at evoking new antibodies.
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