Co-administration of RSV and COVID-19 vaccines is safe and effective in adults aged ≥50 years
Background and Challenge
In a context where respiratory viruses such as SARS‑CoV‑2 and RSV pose simultaneous threats, there has been growing interest in administering both vaccines concurrently to adults aged ≥50 years. Concerns existed that co‑administration might interfere with immune responses, necessitating evaluation of safety and efficacy when the two vaccines are given together.
Study Design and Key Immunogenicity Results
In this trial, 833 participants aged ≥50 years were randomized 1:1 to a co‑administration group or a sequential (control) group. Neutralizing antibodies against RSV‑A and RSV‑B met the non‑inferiority criteria in both groups, with GMT ratios of 1.12 and 1.08, respectively. Neutralizing antibodies against the SARS‑CoV‑2 Omicron XBB.1.5 variant exceeded the predefined margin slightly (GMT ratio 1.31, 95 % CI 1.13–1.51), but were judged not to be of clinical concern.
Safety Profile
Within four days post‑vaccination, the most frequently reported solicited events were injection‑site pain, myalgia, and fatigue, most of which were mild to moderate in intensity. The median duration of these events was ≤3 days, with minimal differences between groups. Serious adverse events and unexpected events occurred at comparable rates, supporting an overall favorable safety profile.
Implications and Outlook
These findings demonstrate that co‑administration of an RSV vaccine and a COVID‑19 mRNA vaccine in adults aged ≥50 years preserves immunogenicity and safety, potentially simplifying immunization schedules and improving vaccine uptake. Future studies may extend this strategy to other age groups and vaccine combinations.
BACKGROUND: This trial evaluated co-administration of the AS01E-adjuvanted respiratory syncytial virus (RSV) prefusion F protein-based vaccine (adjuvanted RSVPreF3) and an Omicron XBB.1.5-based COVID-19 mRNA vaccine in ≥50-year-olds. METHODS: This phase 3, open-label, multi-center trial randomized ≥50-year-olds 1:1 to co-administration (Co-Ad group) or sequential administration approximately one month apart (Control group) of adjuvanted RSVPreF3 and the COVID-19 mRNA vaccine. Primary objectives were to demonstrate non-inferiority of humoral immune responses at one month post-vaccination in terms of RSV-A, RSV-B, and SARS-CoV-2 neutralizing titers, with the upper limit of the 95% confidence interval (CI) of adjusted geometric mean titer (GMT) group ratios (Control/Co-Ad) ≤1.50. Secondary objectives included assessment of reactogenicity up to four days and safety up to six months after vaccination. RESULTS: Overall, 833 participants were vaccinated (Co-Ad: 417; Control: 416). Non-inferiority was achieved for RSV-A (GMT ratio: 1.12 [95% CI: 0.97-1.28]) and RSV-B (GMT ratio: 1.08 [95% CI: 0.94-1.23]), and marginally missed for SARS-CoV-2 Omicron XBB.1.5 (GMT ratio: 1.31 [95% CI: 1.13-1.51]). Within four days post-vaccination, the most frequently reported solicited events were administration-site pain, myalgia, and fatigue. Most solicited events were of mild-to-moderate intensity, and the overall median duration was ≤three days and comparable between groups. Unsolicited and serious adverse events were generally balanced between groups. CONCLUSIONS: Adjuvanted RSVPreF3 co-administered with a COVID-19 mRNA vaccine maintained an acceptable safety profile in ≥50-year-olds. The marginal miss of the non-inferiority criterion for SARS-CoV-2 does not suggest clinically relevant interference. Therefore, the results support the co-administration of these vaccines.
The objective of this study was to determine whether older adults can safely receive two critical respiratory virus vaccines concurrently. Historically, the requirement to administer vaccines separately has complicated scheduling and led to missed doses. By evaluating a co‑administration approach in a randomized clinical trial, the study provides evidence that vaccination efficiency can be increased and patient burden reduced in clinical practice. Ongoing research will explore the extension of this strategy to additional age groups and vaccine combinations.