Why the study?
The emergence of SARS-CoV-2 variants with decreased susceptibility to neutralization created interest in evaluating booster doses and variant-specific vaccines.
Does a single booster dose of mRNA-1273 or variant-modified mRNAs improve neutralization titers against SARS-CoV-2 variants in healthy adults who previously received the mRNA-1273 primary series?
Does a single booster dose of mRNA-1273 or variant-modified mRNAs improve neutralization titers against SARS-CoV-2 variants in healthy adults who previously received the mRNA-1273 primary series?
A single booster dose of mRNA-1273 or variant-modified mRNAs safely increases neutralization titers against SARS-CoV-2 variants to levels comparable to or higher than peak titers after the primary series.
Answers are grounded in this paper and cite their sources.
May support boosters to restore titers in mRNA-1273 recipients; leaves open clinical protection in larger trials.
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.
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Choi et al. (2021) studied this question.
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