Cell: The third mRNA vaccine can better protect against the Omicron variant

Scientists at the Ragon Institute of MGH, MIT and Harvard recently discovered that immunity against SARS-CoV-2's Omicron variant can only be developed after a booster shot of Moderna or Pfizer's mRNA vaccine.

In late November 2021, South African health officials reported that a previously unknown variant of SARS-CoV-2 was spreading rapidly within the country

To find out, Balazs teamed up with researchers such as Dr.

Balazs and colleagues constructed a pseudovirus that mimics the behavior of Omicron, which has 34 mutations in its spike protein that were not found in the original strain of SARS-Cov-2

Next, Garcia-Beltran, working with colleagues at Massachusetts General Hospital, took blood samples from 239 people who had completed their vaccinations and had received one of three COVID-19 vaccines

"Representing diverse populations in the study was important to us," Garcia-Beltran said

The results were surprising

It's unclear why the mRNA booster significantly improved immune protection against Omicron, but Garcia-Beltran believes that one possibility is that the extra doses produced antibodies that bind more tightly to the spike protein, increasing their potency

Balazs noted that the three-dose mRNA vaccine regimen, a booster to the traditional two-dose Pfizer or Moderna vaccine, had slightly lower levels of neutralizing antibodies against Omicron than against the wild-type or delta-variant COVID-19 strains Neutralizing antibody levels

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mRNA-based COVID-19 vaccine boosters induce neutralizing immunity against SARS-CoV-2 Omicron variant

Published: December 23, 2021 DOI: https://doi.