Moderna’s booster significantly increases antibody levels against omicron variant, Cambridge company says

As omicron rages across the U.S. and world, Moderna says its booster dose appears to be effective against the highly contagious COVID-19 variant.

The Cambridge company’s authorized 50-microgram booster of its mRNA vax increased neutralizing antibody levels against omicron by about 37-fold compared to pre-boost levels. The 37-fold booster jump is higher than Pfizer’s 25-fold increase.

A 100-microgram dose that Moderna also tested spiked neutralizing antibody levels by about 83-fold compared to pre-boost levels.

“The dramatic increase in COVID-19 cases from the omicron variant is concerning to all,” said Moderna CEO Stephane Bancel. “However, these data showing that the currently authorized Moderna COVID-19 booster can boost neutralizing antibody levels 37-fold higher than pre-boost levels are reassuring.”

Moderna continues to work on booster candidates to address emerging variants of concern, including the new omicron variant that is running rampant this holiday season.

“To respond to this highly transmissible variant, Moderna will continue to rapidly advance an omicron-specific booster candidate into clinical testing in case it becomes necessary in the future,” Bancel said. “We will also continue to generate and share data across our booster strategies with public health authorities to help them make evidence-based decisions on the best vaccination strategies against SARS-CoV-2.”

The 50-microgram booster and 100-microgram booster testing was done at labs established by the National Institute of Allergy and Infectious Diseases’ Vaccine Research Center and Duke University Medical Center. A preprint submission is being prepared based on the data.

All test groups had low neutralizing antibody levels against omicron prior to boosting. At day 29 post-boost, the authorized 50-microgram booster increased neutralizing geometric mean titers against omicron to 850, which is about 37-fold higher than pre-boost levels.

At day 29 post-boost, the 100-microgram dose booster increased neutralizing geometric mean titers to 2,228, which is about 83-fold higher than pre-boost levels.

Three doses of Pfizer’s mRNA vaccine can knock back the omicron variant by producing a 25-fold increase in antibodies, the company announced earlier this month, but said two doses might not be enough to keep the mutant fully at bay.

“Although two doses of the vaccine may still offer protection against severe disease caused by the Omicron strain, it’s clear from these preliminary data that protection is improved with a third dose of our vaccine,” said Albert Bourla, chairman and CEO of Pfizer.

A preliminary study showed that three doses of the vaccine neutralized omicron with a 25-fold increase in antibodies. Those who only got two vaccine doses saw a reduction in protection against omicron compared to other coronavirus strains.

However, two doses may still protect against severe disease, according to Pfizer. The results are still preliminary, and Pfizer is also working on an omicron-specific vaccine, should it be necessary.