Safety and immunogenicity of SARS-CoV-2 variant mRNA vaccine boosters in healthy adults: an interim analysis.

Journal Article (Journal Article;Multicenter Study)

The emergence of SARS-CoV-2 variants of concern (VOCs) and variants of interest (VOIs) with decreased susceptibility to neutralization has generated interest in assessments of booster doses and variant-specific vaccines. Clinical trial participants who received a two-dose primary series of the COVID-19 vaccine mRNA-1273 approximately 6 months earlier entered an open-label phase 2a study ( NCT04405076 ) to evaluate the primary objectives of safety and immunogenicity of a single booster dose of mRNA-1273 or variant-modified mRNAs, including multivalent mRNA-1273.211. As the trial is currently ongoing, this exploratory interim analysis includes preliminary descriptive results only of four booster groups (n = 20 per group). Immediately before the booster dose, neutralizing antibodies against wild-type D614G virus had waned (P < 0.0001) relative to peak titers against wild-type D614G measured 1 month after the primary series, and neutralization titers against B.1.351 (Beta), P.1 (Gamma) and B.1.617.2 (Delta) VOCs were either low or undetectable. Both the mRNA-1273 booster and variant-modified boosters were safe and well-tolerated. All boosters, including mRNA-1273, numerically increased neutralization titers against the wild-type D614G virus compared to peak titers against wild-type D614G measured 1 month after the primary series; significant increases were observed for mRNA-1273 and mRNA-1273.211 (P < 0.0001). In addition, all boosters increased neutralization titers against key VOCs and VOIs, including B.1.351, P.1. and B.1.617.2, that were statistically equivalent to peak titers measured after the primary vaccine series against wild-type D614G virus, with superior titers against some VOIs. This trial is ongoing.

Full Text

Duke Authors

Cited Authors

  • Choi, A; Koch, M; Wu, K; Chu, L; Ma, L; Hill, A; Nunna, N; Huang, W; Oestreicher, J; Colpitts, T; Bennett, H; Legault, H; Paila, Y; Nestorova, B; Ding, B; Montefiori, D; Pajon, R; Miller, JM; Leav, B; Carfi, A; McPhee, R; Edwards, DK

Published Date

  • November 2021

Published In

Volume / Issue

  • 27 / 11

Start / End Page

  • 2025 - 2031

PubMed ID

  • 34526698

Pubmed Central ID

  • PMC8604720

Electronic International Standard Serial Number (EISSN)

  • 1546-170X

Digital Object Identifier (DOI)

  • 10.1038/s41591-021-01527-y


  • eng

Conference Location

  • United States