Vaccine Makers Seek to Address Omicron SARS-CoV-2 Variant

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The companies are testing their existing vaccines against the new variant of concern and are pursuing variant-specific versions.

A SARS-CoV-2 variant first identified in South Africa was designated on Nov. 26, 2021 as a variant of concern, named Omicron, by the World Health Organization (WHO). Further study is underway to evaluate whether the B.1.1.529 (Omicron) variant is more transmissible or causes more disease and whether current vaccines and treatments continue to be effective countermeasures.

Vaccine makers have been monitoring variants and continuing to evaluate the effectiveness of their vaccines. Pfizer and BioNTech continue to conduct surveillance efforts focused on monitoring for emerging variants. “We are beginning to run neutralization tests on the new Omicron variant of concern and expect to have initial data in the coming weeks,” said a Pfizer spokesperson in a statement. “In the event that a variant emerges that escapes protection of our vaccine, Pfizer and BioNTech expect to be able to develop and produce a tailor-made vaccine against that variant in approximately 100 days, subject to regulatory approval.”

Moderna reported in a Nov. 26, 2021 press release that it was working to test the ability of its current, FDA-authorized 50-µg mRNA-1273 vaccine booster dose to neutralize the Omicron variant and expected data in the coming weeks. The company said that if the 50-µg dose proved insufficient, it would turn to a 100-µg booster dose that is already under study to investigate its neutralizing protection against Omicron. Moderna also has two multivalent booster candidates, designed to anticipate mutations such as those that have emerged in the Omicron variant, in clinical studies. According to the press release, the first candidate (mRNA-1273.211) includes several mutations present in the Omicron variant that were also present in the Beta variant of concern, and a second multivalent candidate (mRNA-1273.213) includes many of the mutations present in the Omicron variant that were also present in the Beta and Delta variants. The company said it would also advance an Omicron-specific booster candidate (mRNA-1273.529). Moderna said it was advancing these three lines of defense in parallel.

“From the beginning, we have said that as we seek to defeat the pandemic, it is imperative that we are proactive as the virus evolves. The mutations in the Omicron variant are concerning, and, for several days, we have been moving as fast as possible to execute our strategy to address this variant,” said Stéphane Bancel, CEO of Moderna, in the press release.


Johnson & Johnson said in a Nov. 29, 2021 media statement that it was confident in the robust immune response of its COVID-19 vaccine against variants to date in clinical studies. “We will not be complacent. Building on our long-term collaboration with scientists on the ground in South Africa and the ongoing real world effectiveness studies being conducted with the Johnson & Johnson COVID-19 vaccine, we will work together to generate new data on Omicron,” said Mathai Mammen, global head, Janssen Research & Development, Johnson & Johnson, in the statement. “In parallel, we have begun work to design and develop a new vaccine against Omicron and will rapidly progress it into clinical studies if needed.”

According to a Reuters report on Nov. 26, 2021, AstraZeneca said it was examining the impact of Omicron on its vaccine and was collecting real-world data. The company also said it was testing its long-acting antibody combination against the variant and was hopeful it would retain efficacy.

Sources: WHO, Pfizer, Moderna, Johnson & Johnson, Reuters