Neutralizing antibody levels against the Omicron variant declined 6 months after a booster dose of the Moderna COVID-19 vaccine but remained detectable in all participants, according to new data published in The New England Journal of Medicine.

The study was conducted at laboratories established by the National Institute of Allergy and Infectious Diseases’ (NIAID) Vaccine Research Center and Duke University Medical Center. Serum samples were collected from 20 booster recipients each of mRNA-1273 at the 50mcg and 100mcg dose levels, multivalent candidate mRNA-1273.211 at the 50mcg and 100mcg dose levels, and multivalent candidate mRNA-1273.213 at the 100mcg dose level. Seven months after the primary series and prior to the booster dose, Omicron neutralization was detected in only 55% of participants. 

Findings showed that neutralizing antibody levels against Omicron increased 20-fold with a 50mcg booster dose of mRNA-1273 compared with peak preboost levels. When compared with peak levels at day 29 postboost, neutralizing antibody levels were found to decline by 6.3-fold at 6 months after the booster but remained detectable in all participants. Over the same time period, neutralizing antibody levels were found to decline faster against the Omicron variant than for the wild-type virus (D614G; 2.3 times lower 6 months after booster).

Continue Reading

Results demonstrated that the 100mcg booster dose of mRNA-1273, mRNA-1273.211 or mRNA-1273.213 generated similar neutralizing antibody levels, with neutralizing titers being 2.5- to 2.6-fold higher compared with the 50mcg booster dose of mRNA-1273.

The Company also announced that the first participant has been dosed in a phase 2 study evaluating an Omicron-specific booster candidate (mRNA-1273.529).

“Given the long-term threat demonstrated by Omicron’s immune escape, we are advancing our Omicron-specific variant vaccine booster candidate and we are pleased to begin this part of our phase 2 study,” said Stéphane Bancel, CEO of Moderna. “We are also evaluating whether to include this Omicron-specific candidate in our multivalent booster program.


  1. Moderna announces first participant dosed in phase 2 study of Omicron-specific booster candidate and publication of data on booster durability against Omicron variant. News release. Moderna Inc. January 26, 2022. Accessed January 27, 2022.
  2. Pajon R, Doria-Rose N, et al. SARS-CoV-2 Omicron variant neutralization after mRNA-1273 booster vaccination. Published January 26, 2022. New England Journal of Medicine. doi: 10.1056/NEJMc2119912.

This article originally appeared on MPR