Background:Coadministering vaccines can effectively enhance vaccination uptake in adults. Despite the potential benefits, there is limited data supporting this practice. We investigated the immunogenicity and safety of coadministering coronavirus disease 2019 (COVID-19) messenger RNA, influenza, and pneumococcal (PPSV23) vaccines in adults.
Methods:As part of the national vaccination program, 3104 adults received a fourth dose (second booster) of an messenger RNA COVID-19 vaccine alone or coadministered with an influenza vaccine, with or without PPSV23 from January to December 2022. We measured severe acute respiratory syndrome coronavirus 2 anti-spike and anti-receptor binding domain (RBD) immunoglobulin G (IgG) concentrations and neutralization activity before and 1 month after vaccination. We estimated the odds of a ≥2-fold geometric mean fold rise (GMFR) and adverse events (AEs) using logistic regression models.
Results:The median age of the 3104 participants was 70 years (interquartile range: 60–77); 1670 (54%) were female. Anti-spike IgG GMFRs were 1.95, 1.56, and 1.42, whereas for neutralization activity, values were 8.99, 12.42, and 8.23, in the COVID-19, COVID-19 + influenza, and COVID-19 + influenza + PPSV23 groups, respectively. The adjusted odds of a ≥2-fold anti-spike IgG GMFR were 0.64 (P < .001) and 0.43 (P < .001), and for neutralization activity, 0.96 (P = .833) and 0.97 (P = .954), for COVID-19 + influenza and COVID-19 + influenza + PPSV23, respectively. The odds for anti-RBD GMFRs followed similar patterns. Systemic AEs were more common in the COVID-19 + influenza + PPSV23 group (adjusted odds ratio: 2.04, P < .001), though no serious AEs were reported.
Conclusions:Coadministering COVID-19, influenza, and PPSV23 vaccines seems feasible, without significantly impairing neutralizing antibody responses. These findings support the recommendation for vaccine coadministration in adults.