Phil Kerpen, a conservative opinion-writer and president of the "American Commitment," claimed that "there is literally zero evidence that these vaccines prevent Omicron infections" on Twitter. His tweet was posted on January 7th, as the U.S. Supreme Court weighs in on President Biden's vaccine mandate for large businesses and health care facilities. This tweet has already been shared widely. We find this claim false. There is growing evidence that the currently available MRNA vaccines provide some protection against the Omicron variant (B.1.1.529) of the SARS-COV-2 virus, the coronavirus that causes COVID-19. According to the CDC, preliminary results for Omicron from South Africa showed that the Pfizer vaccine provided 70% protection against COVID-19 hospitalization and 33% against infection, during the current Omicron wave. Granted, the protection is reduced compared with the Delta variant (93% for hospitalization and 80% for infection). Moderna said its COVID-19 booster does appear to provide protection against the omicron variant.
More recently, a report by the United Kingdom's Health Security Agency, drawing on data collected during the country's Omicron surge in late December, found that, while vaccines protect much less against catching COVID-19 with Omicron than with Delta, protection against hospitalization remains high. Protection against hospitalization waned over time after a second dose, but a booster shot increased it again.
A letter posted on December 29th in the New England Journal of Medicine discusses how researchers compared the vaccine effectiveness against Covid-19 hospitalization associated with the Omicron variant during the period from November 15 to December 7 in South Africa. They found that vaccine effectiveness was rated at 70%, compared to 93% during the peak of the Delta variant (September 1-October 31, 2021).
A study recently published on the medRxiv preprint server concluded that two vaccine doses are highly ineffective against infection by the Omicron variant.
Pfizer said that while two doses of its vaccine may not be protective enough to prevent infection, lab tests showed a booster shot increased by 25-fold people's levels of virus-fighting antibodies.
Moderna has stated that its two-dose vaccine remained "durable" six months after the second shot, immunity against the coronavirus will continue to wane and eventually diminish vaccine efficacy.
According to a study by researchers at the Ragon Institute of MGH, MIT and Harvard in the journal Cell found that an additional “booster” dose of Moderna or Pfizer mRNA-based vaccine is needed to provide immunity against the Omicron variant. The study’s results strongly support the CDC’s advice that COVID-19 booster shots are appropriate for anyone 16 and older, and that mRNA vaccines are preferred.
While our existing mRNA vaccines still offer some protection against Omicron, there appears to be a significant decline in neutralizing antibodies against this variant in people who have received two shots of an mRNA vaccine.
However, initial results of studies conducted both in the lab and in the real world show that people who get a booster shot, or third dose of vaccine, may be better protected. Though these data are preliminary, they suggest that getting a booster will help protect people already vaccinated from breakthrough or possible severe infections with Omicron during the winter months.