The omicron variant contains a number of mutations that experts say could help it partially evade protection provided by Covid-19 vaccines. In response, drugmakers have announced plans to adapt their Covid-19 vaccines to the variant's mutations.

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Could the omicron variant evade vaccine immunity?

The omicron variant contains around 50 mutations, about 30 of which relate to the amino acids on omicron's spike protein—specifically, the area of the spike protein that attaches to human cell receptors, Science reports.

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Jesse Bloom, an evolutionary biologist at the Fred Hutchinson Cancer Research Center, said these differences could make the variant effective at dodging the human antibodies prompted by existing vaccines or infections. In particular, a mutation called E484A could change the shape of an important site on the spike protein that antibodies recognize, which could render those antibodies less potent.

Bloom said that he expects people with existing immunity against Covid-19 will maintain some protection against the omicron variant. But, he said, that protection will likely be diminished. "I would expect, based on this particular combination of mutations, that the drop in neutralization is larger than for all the other major variants," he said.

Separately, Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, also expressed concerns about the "troublesome" mutations in omicron.

"[T]he profile of the mutations strongly suggest that … it might evade immune protection that you would get, for example, from a monoclonal antibody or from the convalescent serum after a person's been infected and possibly even against some of the vaccine-induced antibodies," he said.

However, NIH Director Francis Collins said he believed that since Covid-19 vaccines have been effective against other coronavirus variants, they're likely to be effective against omicron as well. "Given that history, we expect that most likely the current vaccines will be sufficient to provide protection," Collins said. "And especially the boosters will give that additional layer of protection because there's something about the booster that causes your immune system to really expand its capacity against all kinds of different spike proteins, even ones it hasn't seen before"

If current vaccines falter, how quickly could new ones be ready?

In response to omicron's emergence, drug manufacturers have announced plans to test their vaccines or develop new ones to target omicron, CNBC reports.

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Vaccines that are based on mRNA, such as those manufactured by Pfizer-BioNTech and Moderna, could be altered especially quickly. Those vaccines prompt the body to create specific proteins that mimic the coronavirus's spike, and vaccine manufacturers can readily change the exact proteins their vaccines are coded to create.

Moderna CEO Stéphane Bancel previously told the Daily Briefing that his company designed its vaccine against the original coronavirus strain in just two days.

However, even if a new mRNA vaccine is designed quickly, manufacturers would need more time to test the vaccine in clinical trials and to scale up its production to reach millions of people.

Pfizer and BioNTech said they "have immediately initiated investigations" on the variant and can quickly adapt their vaccine if necessary. "[This] data will provide more information about whether [omicron] could be an escape variant that may require an adjustment of our vaccine if the variant spreads globally," Pfizer and BioNTech said.

They added, "Pfizer and BioNTech have taken actions months ago to be able to adapt the mRNA vaccine within six weeks and ship initial batches within 100 days in the event of an escape variant."

For its part, Moderna in a statement on Friday said it had three potential avenues to adapt its vaccine to combat the omicron variant if needed:

• Providing a full-dose booster of its current coronavirus vaccine. Up until now, booster doses of the Moderna vaccine have contained only half the original dosage.
  
  
• Advancing a multivalent vaccine candidate that is already in clinical trials, which was designed to target some of the same mutations that appear in omicron.
  
  
• Designing a new vaccine specifically targeted at omicron, which it suggested could advance "to clinical testing in 60-90 days."

Other vaccine manufacturers are also responding quickly to omicron's emergence.

Johnson & Johnson on Friday announced it is testing its existing vaccine against the variant. "We are closely monitoring newly emerging Covid-19 virus strains with variations in the [coronavirus] spike protein and are already testing the effectiveness of our vaccine against the new and rapidly spreading variant first detected in southern Africa," the company said.

AstraZeneca also announced it is investigating how well its vaccine, developed alongside Oxford University, can protect against the omicron variant. "AstraZeneca is also already conducting research in locations where the variant has been identified, namely in Botswana and Eswatini," AstraZeneca said.

And Novavax announced it's also working on a vaccine to specifically combat omicron. A spokesperson suggested that testing and manufacturing of the vaccine will likely "take a few weeks." But the company has not yet filed for approval of its existing coronavirus vaccine in the United States. (Kupferschmidt, Science, 11/27; Choi, The Hill, 11/28; Vakil, The Hill, 11/28; Kimball/Towey, CNBC, 11/26; Lonas, The Hill, 11/27)