No immunological interference or safety concerns when adjuvanted recombinant zoster vaccine is coadministered with a COVID-19 mRNA-1273 booster vaccine in adults aged 50 years and older: A randomized trial

Background: There is growing consensus that COVID-19 booster vaccines may be coadministered with other age-appropriate vaccines. Adding to the limited available data supporting coadministration, especially with adjuvanted vaccines, could enhance vaccine coverage in adults. Methods: In this phase 3, randomized, open-label study, eligible adults aged [≥]50 years were randomly assigned (1:1) to receive mRNA-1273 (50g) booster vaccination and a first dose of recombinant zoster vaccine (RZV1) 2 weeks apart (Seq group) or concomitantly (Coad group). The second RZV dose (RZV2) was administered 2 months post RZV1 in both groups. Primary objectives were noninferiority of anti-glycoprotein E and anti-Spike protein antibody responses in the Coad group compared to the Seq group. Safety and further immunogenicity assessments were secondary objectives. Results: 273 participants were randomized to the Seq group, 272 to the Coad group. Protocol-specified non-inferiority criteria were met. The adjusted geometric mean concentration ratio (Seq/Coad) was 1.01 (95% confidence interval [CI], 0.89-1.13) for anti-gE antibodies 1-month post-RZV2, and 1.09 (95% CI 0.90-1.32) for anti-Spike antibodies 1-month post-mRNA-1273 booster. No clinically relevant differences were observed in overall frequency, intensity, or duration of adverse events between the 2 study groups. Most solicited adverse events were mild/moderate in intensity, each with median duration [≤]2.5 days. Administration site pain and myalgia were the most frequently reported in both groups. Conclusions: Coadministration of mRNA-1273 booster vaccine with RZV in adults aged [≥]50 years was immunologically noninferior to sequential administration and had a safety and reactogenicity profile consistent with both vaccines administered sequentially (clinicaltrials.gov NCT05047770).