Strong humoral immune responses against SARS-CoV-2 Spike after BNT162b2 mRNA vaccination with a 16-week interval between doses.

The standard regimen of the BNT162b2 mRNA vaccine for SARS-CoV-2 includes two doses administered three weeks apart. However, some public health authorities spaced these doses, raising questions about efficacy. We analyzed longitudinal humoral responses against the D614G strain and variants of concern for SARS-CoV-2 in a cohort of SARS-CoV-2-naive and previously infected individuals who received the BNT162b2 mRNA vaccine with sixteen weeks between doses. While administering a second dose to previously infected individuals did not significantly improve humoral responses, these responses significantly increased in naive individuals after a 16-week spaced second dose, achieving similar levels as in previously infected individuals. Comparing these responses to those elicited in individuals receiving a short (4-week) dose interval showed that a 16-week interval induced more robust responses among naive vaccinees. These findings suggest that a longer interval between vaccine doses does not compromise efficacy and may allow greater flexibility in vaccine administration. [Display omitted] • One mRNA vaccine dose induces robust humoral responses in convalescent donors • An extended interval between doses leads to high humoral responses in naive donors • These responses are stronger than in naive donors vaccinated with a short interval • Vaccine-elicited antibodies decline more rapidly in naive than convalescent donors Tauzin et al. characterize longitudinal humoral responses induced with an extended BNT162b2 vaccine interval between doses. They show that delaying the second dose in naive individuals elicits higher humoral responses than in those receiving a four-week interval. Vaccinated convalescent individuals present higher responses that don't improve after a boost. [ABSTRACT FROM AUTHOR]