Combining RSV and Flu Vaccines Found Safe and Effective, may Potentially Ease Vaccine Burden: Study

UK: A Phase III randomized trial demonstrated that administering the RSV prefusion F protein vaccine (Arexvy) simultaneously with the adjuvanted seasonal quadrivalent influenza vaccine elicited a robust immune response and was safe for older adults. The findings were published online in Clinical Infectious Diseases on August 05, 2024.

Respiratory syncytial virus (RSV) is the major cause of acute respiratory illness. Senior citizens, infants, and individuals with medical conditions such as lung disease, heart disease, and diabetes are at major risk of developing RSV. It infects the lungs and respiratory tract. In adults and older, healthy children, respiratory syncytial virus (RSV) symptoms are mild and typically mimic the common cold. Self-care measures are usually all that's needed to relieve any discomfort. Considering this, Rebecca Clark, from Layton Medical Centre, Blackpool, United Kingdom, et.al conducted a study to evaluate the co-administration of adjuvanted seasonal quadrivalent influenza vaccine and respiratory syncytial virus prefusion F protein-based vaccine in ≥65-year-olds.

For this purpose, the research team conducted a randomized, open-label trial involving 37 centers from Belgium, Finland, France, Spain, and the United Kingdom. Declaration of Helsinki from 14 October 2022 to 17 July 2023. Good Clinical Practice and Regulatory Requirements conducted the study. The protocol of the study was approved by the relevant ethics committees.

The study included 1045 participants and the per-protocol sets included 471 Co-Ad and 400 Control participants for the post-vaccination flu analysis and 471 Co-Ad and 374 Control participants for the post-vaccination RSV analysis. Adults with aged ≥65 years and those with chronic stable medical conditions were included in the study, Individuals with suspected or confirmed immunosuppressive or immunodeficient conditions resulting from disease or therapy, and individuals who had received an influenza vaccine within 6 months before FLU- aQIV were administered in the study. Individuals who received the individuals who received RSV vaccine were excluded from the study.

The findings revealed that:

• In terms of HI titers for the A/Victoria (H1N1), B/Victoria, and B/Yamagata influenza strains as well as RSV-A neutralization titers, non-inferiority of FLU-aQIV and RSVPreF3 OA co-administered with sequential administration was shown, but not for A/Darwin (H3N2) HI titers (95%).
• Using a microneutralization test, the immune response to A/Darwin(H3N2) was further evaluated post-hoc. The post-vaccination adjusted GMT ratio (Control/Co-Ad) was 1.23 (95%) indicating that the immunological response to A/Darwin(H3N2) was sufficient after co-administration.
• 95% of the groups' RSV-B neutralization titers were similar.
• The majority of solicited adverse events were mild to moderate and temporary, but the rates of serious and unsolicited adverse events were similar across groups.

“The adjuvanted RSV prefusion F protein-based vaccine (RSVPreF3 OA, Arexvy, GSK) is effective against RSV-related lower respiratory tract disease, demonstrates strong immunogenicity, and has an acceptable safety profile for adults aged 60 and older”, researchers concluded.

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