Safety, Tolerability, and Immunogenicity of the Pneumococcal Vaccines PPSV23 or PCV15 Co-Administered with a Booster Dose of mRNA-1273 SARS-CoV-2 Vaccine in Healthy Adults ≥50 Years of Age.

Background/Objectives: Streptococcus pneumoniae with, or following, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has been associated with increased mortality, particularly in older adults. However, vaccination can be an effective preventative measure. This Phase 3 study (NCT05158140) assessed the immunogenicity and safety of co-administering the SARS-CoV-2 vaccine mRNA-1273 with the 23-valent pneumococcal polysaccharide vaccine (PPSV23) or the 15-valent pneumococcal conjugate vaccine (PCV15). Methods: Participants were healthy adults ≥50 years of age who had previously received a two-dose primary series of mRNA-1273 ≥5 months before the first study visit and may have received a booster dose of mRNA-1273 ≥4 months prior to the first study visit. Participants were randomized (1:1:1:1) to receive mRNA-1273 concomitantly with PPSV23 or PCV15 on Day 1 followed by placebo on Day 30, or sequentially with mRNA-1273 and placebo on Day 1 and PPSV23 or PCV15 on Day 30. The primary study endpoints were pneumococcal-serotype-specific opsonophagocytic activity (OPA) geometric mean titers (GMTs) and SARS-CoV-2-specific binding antibody GMTs at 30 days after vaccination, as well as safety and tolerability following vaccination. Results: In total, 850 adults participated in the study. Serotype-specific OPA GMTs at 30 days post-vaccination with PPSV23 or PCV15 were generally comparable between the concomitant and sequential groups. SARS-CoV-2-specific GMTs increased in all groups from pre-vaccination to 30 days post-vaccination with mRNA-1273, with a consistent response between concomitant and sequential groups. Safety profiles were comparable across study groups. Conclusions: Co-administration of mRNA-1273 with PPSV23 or PCV15 in healthy adults ≥50 years of age was immunogenic and well tolerated. [ABSTRACT FROM AUTHOR]