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Ciara O'Rourke
By Ciara O'Rourke November 30, 2021

Claims that vaccines won’t work against omicron variant are premature and not based in science

If Your Time is short

  • Speculation abounds, but we don’t yet know how well the existing COVID-19 vaccines will work against the omicron variant, or if they will need tweaks to fight it. 

If you google "omicron variant" and "vaccine," you’ll find a lot of speculation, expectations and unknowns. 

"Omicron vs. Delta: More mutations don’t necessarily make a meaner COVID-19 virus," says one CNN headline

"COVID-19 vaccine effectiveness will likely drop against omicron variant, Moderna CEO says," Fox Business reported on Nov. 30

In the Wall Street Journal that day: "Omicron unlikely to cause severe illness in vaccinated people, BioNTech founder says." 

The omicron variant of the coronavirus, recently declared by the World Health Organization as a "variant of concern," has fueled fears about how well the COVID-19 vaccines that are currently available will fare against it. But some takes are being shared prematurely. 

"Breaking news," one Nov. 26 Facebook post says. "None of your previous vaccines will protect you now from the emerging variant omicron." 

This post was flagged as part of Facebook’s efforts to combat false news and misinformation on its News Feed. (Read more about our partnership with Facebook.)

As the aforementioned news headlines illustrate, researchers don’t yet know how well the vaccines will protect against the new variant. We’ve previously dug into what we do know about omicron and other coronavirus variants. In short: While the variant includes some potentially worrisome mutations, it’s not guaranteed to become as strong as or stronger than the delta variant. It will take a few weeks to know whether it’s significantly more transmissible, whether it causes worse illness, and whether it will be able to evade our current vaccines. 

As of now, according to the WHO, "it is not yet clear" whether omicron is more transmissible when compared to other variants or if it causes more severe disease. Preliminary data suggests that hospitalization rates are rising in South Africa, where scientists first detected the variant, but, the WHO said, "this may be due to increasing overall numbers of people becoming infected, rather than a result of specific infection with omicron."

As of Nov. 30, the presence of the variant had been confirmed in at least 20 countries, and health leaders in western Europe announced they had found samples that predate those found in southern Africa.

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The WHO didn’t offer much information about vaccine effectiveness against omicron as of Nov. 28, noting that it was working to understand "the potential impact of this variant on our existing countermeasures, including vaccines." Still, the WHO said, "current vaccines remain effective against severe disease and death." 

Scientists are cautiously optimistic.

"Most scientists believe we should still have protection against severe disease with vaccinations, and vaccination remains the mainstay of control," Dr. Monica Gandhi, professor of medicine at the University of California-San Francisco, told PolitiFact. 

Studies are underway to assess vaccine performance against omicron. The New York Times reported on Nov. 28 that "early findings are a mixed picture."

Experts old the Times that "the variant may be more transmissible and better able to evade the body’s immune responses, both to the vaccination and to natural infection, than prior versions of the virus" and "vaccines may well continue to ward off severe illness and death, although boosters may be needed to protect most people." 

Pfizer’s chief scientific officer compared the company’s researchers to firefighters, STAT reported — they don’t know how serious the blaze will be, but they need to prepare for the worst, which could potentially require new vaccines. 


Moderna’s chief executive, meanwhile, told the Financial Times that he thinks "there is no world" in which the vaccines will be as effective against omicron as they are against the delta variant. 

Jesse Bloom, an evolutionary biologist at the Fred Hutchinson Cancer Research Center in Seattle, told the New York Times that "probably in a few weeks we’ll have a better sense of how much this variant is spreading and how necessary it might be to push forward with a variant vaccine." 

But to claim definitively in November 2021 that the vaccines won’t work against omicron is not accurate. It’s yet unknown and subject to more research. 

We rate this claim False.


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Claims that vaccines won’t work against omicron variant are premature and not based in science

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