The Association Between Pre-Booster Vaccination Antibody Levels and the Risk of SARS-CoV-2 Infection.

The correlation between Anti-SARS-CoV-2 antibody levels and infection was reported. Here, we estimated the role of pre-fourth-dose levels using data from 1,098 health-care-workers. The risk of infection was reduced by 46% (95% CI: 29-59%) with a 10-fold increase in pre-booster levels. Pre-booster antibody levels could be used to optimally time boosters.

Comparing immunogenicity and efficacy of two different mRNA-based COVID-19 vaccines as a fourth dose; six-month follow-up, Israel, 27 December 2021 to 24 July 2022.

We assess the immunogenicity and efficacy of Spikevax and Comirnaty as fourth dose COVID-19 vaccines. Six months post-fourth-dose, IgG levels were higher than pre-fourth dose at 1.58-fold (95% CI: 1.27-1.97) in Spikevax and 1.16-fold (95% CI: 0.98-1.37) in Comirnaty vaccinees. Nearly 60% (159/274) of vaccinees contracted SARS-CoV-2. Infection hazard ratios (HRs) for Spikevax (0.82; 95% CI: 0.62-1.09) and Comirnaty (0.86; 95% CI: 0.65-1.13) vaccinees were similar, as were substantial-disease HRs, i.e. 0.28 (95% CI: 0.13-0.62) and 0.51 (95% CI: 0.27-0.96), respectively.