Antibody Response to Omicron BA.4–BA.5 Bivalent Booster

This correspondence reports findings from a study assessing neutralizing antibody and T-cell responses following administration of bivalent mRNA Covid-19 boosters targeting the BA.4–BA.5 variants. Compared to the original monovalent vaccines, bivalent boosters did not elicit markedly superior antibody responses across SARS-CoV-2 strains. Titers were highest against the ancestral D614G strain, while responses against other Omicron sublineages were modest. The authors raise concerns about immune imprinting from prior antigen exposure and suggest further longitudinal studies to evaluate sustained immunity.

This correspondence reports findings from a study assessing neutralizing antibody and T-cell responses following administration of bivalent mRNA Covid-19 boosters targeting the BA.4–BA.5 variants. Compared to the original monovalent vaccines, bivalent boosters did not elicit markedly superior antibody responses across SARS-CoV-2 strains. Titers were highest against the ancestral D614G strain, while responses against other Omicron sublineages were modest. The authors raise concerns about immune imprinting from prior antigen exposure and suggest further longitudinal studies to evaluate sustained immunity.