Durability of mRNA-1273 vaccine–induced antibodies against SARS-CoV-2 variants

Description A boost for boosters The evolution of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern poses a potential obstacle to achieving vaccine-induced immunity. Pegu et al. examined how viral variants, including the B.1.351 (Beta) and B.1.617.2 (Delta) variant, affected the immune response in a small number of individuals who received the Moderna mRNA-1273 vaccine. By analyzing sera obtained 6 months after the second shot in the primary vaccine series, the researchers found that neutralizing antibody titers persisted against all variants tested. However, neutralizing antibodies against the B1.351 variant had dropped considerably by 6 months, and some individuals had weak, and in some cases no, neutralizing activity. These data may help to guide public health policies regarding additional booster vaccinations. —PNK Most individuals vaccinated with mRNA-1273 develop functional antibodies against SARS-CoV-2 variants for at least 6 months. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) mutations may diminish vaccine-induced protective immune responses, particularly as antibody titers wane over time. Here, we assess the effect of SARS-CoV-2 variants B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), B.1.429 (Epsilon), B.1.526 (Iota), and B.1.617.2 (Delta) on binding, neutralizing, and angiotensin-converting enzyme 2 (ACE2)–competing antibodies elicited by the messenger RNA (mRNA) vaccine mRNA-1273 over 7 months. Cross-reactive neutralizing responses were rare after a single dose. At the peak of response to the second vaccine dose, all individuals had responses to all variants. Binding and functional antibodies against variants persisted in most subjects, albeit at low levels, for 6 months after the primary series of the mRNA-1273 vaccine. Across all assays, B.1.351 had the lowest antibody recognition. These data complement ongoing studies to inform the potential need for additional boost vaccinations.