Omicron Variant: Moderna Announces Updates to SARS-CoV-2 Strategy for Variants of Concern


The Omicron variant was first identified in South Africa on November 24, 2021.

A 3-pronged strategy is underway to address new SARS-CoV-2 variants of concern, including the Omicron variant, according to a Moderna press release.1

Omicron—first detected in South Africa on November 24, 20212—includes Delta SARS-CoV-2 mutations that increase transmissibility and Beta and Delta SARS-CoV-2 mutations that promote immune escape. This combination of mutations, according to a company press release, “represents a significant potential risk to accelerate the waning of natural and vaccine-induced immunity.”

Because booster doses are the only strategy currently available to address waning immunity, Moderna has implemented the following updates to their strategy to address SARS-CoV-2 variants of concern.

Moderna has already tested a higher dose booster of mRNA-1273 (100 µg) in healthy adults in a safety and immunogenicity study of 306 adults, and the dose has also been studied by the National Institutes of Health. A 100 µg dose has “generally resulted in the highest neutralizing titers against prior SARS-CoV-2 strains.” Efforts are currently underway to test sera from high-dose booster recipients to determine if this dose provides “superior neutralizing protection” against Omicron.

Moderna has already begun studying 2 multi-valent booster candidates designed to anticipate mutations like those that have emerged with Omircon. The first—mRNA-1273.211—includes several mutations found in the Omircon variant that were also presented in the Beta variant. This dosing was completed in a “potentially pivotal” study of safety and immunogenicity at both the 50 µg and 100 µg doses in 300 and 584 adults, respectively.

The mRNA-1273.213 candidate includes “many” of the Omicron mutations that were present in both Beta and Delta variants. Dosing (100 µg) has been completed in 584 healthy adults; the company intends to evaluate the 50 µg dose in 584 participants.

Moderna also plans to expand sera testing from both completed and ongoing multi-valent booster studies to determine if either of these booster candidates provides superior neutralizing protection.

Finally, Modern plans to rapidly advance an Omicron-specific booster candidate, mRNA-1273.529. This booster follows others specific to the Beta and Delta variants.

“The mutations in the Omicron variant are concerning…and we have been moving as fast as possible to execute our strategy to address this variant,” said Stéphanie Bancel, Moderna CEO, in a company press release.1


  1. Moderna announces strategy to address Omicron (B.1.1.529) SARS-CoV-2 varianat. News release. Moderna. November 26, 2021. Accessed November 30, 2021.
  2. Classification of Omicron (B.1.1.529): SARS-CoV-2 variant of concern. World Health Organization. Published November 26, 2021. Accessed November 30, 2021. 
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