A Bivalent Omicron-Containing Booster Vaccine Against Covid-19
Overview
Authors
Affiliations
Background: The safety and immunogenicity of the bivalent omicron-containing mRNA-1273.214 booster vaccine are not known.
Methods: In this ongoing, phase 2-3 study, we compared the 50-μg bivalent vaccine mRNA-1273.214 (25 μg each of ancestral Wuhan-Hu-1 and omicron B.1.1.529 [BA.1] spike messenger RNAs) with the previously authorized 50-μg mRNA-1273 booster. We administered mRNA-1273.214 or mRNA-1273 as a second booster in adults who had previously received a two-dose (100-μg) primary series and first booster (50-μg) dose of mRNA-1273 (≥3 months earlier). The primary objectives were to assess the safety, reactogenicity, and immunogenicity of mRNA-1273.214 at 28 days after the booster dose.
Results: Interim results are presented. Sequential groups of participants received 50 μg of mRNA-1273.214 (437 participants) or mRNA-1273 (377 participants) as a second booster dose. The median time between the first and second boosters was similar for mRNA-1273.214 (136 days) and mRNA-1273 (134 days). In participants with no previous severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, the geometric mean titers of neutralizing antibodies against the omicron BA.1 variant were 2372.4 (95% confidence interval [CI], 2070.6 to 2718.2) after receipt of the mRNA-1273.214 booster and 1473.5 (95% CI, 1270.8 to 1708.4) after receipt of the mRNA-1273 booster. In addition, 50-μg mRNA-1273.214 and 50-μg mRNA-1273 elicited geometric mean titers of 727.4 (95% CI, 632.8 to 836.1) and 492.1 (95% CI, 431.1 to 561.9), respectively, against omicron BA.4 and BA.5 (BA.4/5), and the mRNA-1273.214 booster also elicited higher binding antibody responses against multiple other variants (alpha, beta, gamma, and delta) than the mRNA-1273 booster. Safety and reactogenicity were similar with the two booster vaccines. Vaccine effectiveness was not assessed in this study; in an exploratory analysis, SARS-CoV-2 infection occurred in 11 participants after the mRNA-1273.214 booster and in 9 participants after the mRNA-1273 booster.
Conclusions: The bivalent omicron-containing vaccine mRNA-1273.214 elicited neutralizing antibody responses against omicron that were superior to those with mRNA-1273, without evident safety concerns. (Funded by Moderna; ClinicalTrials.gov number, NCT04927065.).
Omole T, Pelayo E, Weinberg A, Chalkias S, Endale Z, Tamms G Vaccines (Basel). 2025; 13(2).
PMID: 40006738 PMC: 11860627. DOI: 10.3390/vaccines13020192.
Lee J, Sachithanandham J, Lee J, Shapiro J, Li M, Sitaris I Microbiol Spectr. 2025; 13(3):e0219024.
PMID: 39887251 PMC: 11878001. DOI: 10.1128/spectrum.02190-24.
Tometten I, Brandt T, Schlotz M, Stumpf R, Landmann S, Kantauskaite M Front Immunol. 2025; 15:1476294.
PMID: 39877366 PMC: 11772199. DOI: 10.3389/fimmu.2024.1476294.
An Update on Anti-COVID-19 Vaccines and the Challenges to Protect Against New SARS-CoV-2 Variants.
Mambelli F, de Araujo A, Farias J, de Andrade K, Ferreira L, Minoprio P Pathogens. 2025; 14(1).
PMID: 39860984 PMC: 11768231. DOI: 10.3390/pathogens14010023.
Cruz P, Lam J, Abdalla J, Bell S, Bytyci J, Brosh-Nissimov T Vaccines (Basel). 2025; 13(1).
PMID: 39852798 PMC: 11768488. DOI: 10.3390/vaccines13010019.