Safety of simultaneous administration of adjuvanted zoster vaccine and adjuvanted flu vaccine

Novel nonaluminum adjuvants are immunostimulants used in vaccines to improve immunogenicity and efficacy. Adjuvanted inactivated influenza vaccine (Fluad) and adjuvanted recombinant zoster vaccine (Shingrix) contain novel adjuvants. Fluad, a trivalent adjuvanted influenza vaccine (and Fluad Quadrivalent, not marketed in Canada) contain the novel adjuvant MF-59, a squalene-based oil-in-water emulsion. Shingrix, an adjuvanted recombinant zoster vaccine in suspension form, contains the novel adjuvant AS01B.1 Data are limited on the comparative safety of the simultaneous administration of these vaccines. To address this issue, U.S. researchers compared the safety and reactogenicity after simultaneous doses of Shingrix (dose 1) and Fluad Quadrivalent versus simultaneous doses of Shingrix (dose 1) and quadrivalent high-dose inactivated influenza vaccine (Fluzone High-Dose Quadrivalent), with the vaccines administered in opposite arms.1The randomized blinded clinical trial was conducted in community-dwelling adults (≥ 65 years of age) at two U.S. centres during the 2021–2022 and 2022–2023 flu seasons.1 The primary outcome was the proportion of participants with one or more severe solicited adverse reactions during days 1-to-8, using a noninferiority test (10% noninferiority margin). Additional outcome measures included serious adverse events and adverse events of clinical interest during days 1-to-43 of the study period. Patients were also stratified according to age (65–69 and ≥ 70 years).1Results showed the following:A total of 267 adults (median age, 71 years; 51.3% men) were randomized; 130 received simultaneous Shingrix and Fluad Quadrivalent, while 137 received simultaneous Shingrix and Fluzone High-Dose Quadrivalent. The proportion of patients reporting one or more severe reactions after simultaneous administration of both adjuvanted vaccines (Shingrix and Fluad Quadrivalent; 15 of 115 [11.5%]) was noninferior (not higher) compared with simultaneous Shingrix and Fluzone High-Dose Quadrivalent (17 of 119 [12.5%]) (absolute difference, −1.0% [95%CI, −8.9% to 7.1%]). No significant differences were observed in the number of serious adverse events or adverse events of clinical interest between the two groups.Clinically similar patterns of severe reactions were seen among participants aged 65–69 years and those aged ≥ 70 years.Postvaccination effect on health-related quality of life was similar between the two groups.1The authors comment that to their knowledge, this is the first randomized clinical trial directly comparing the safety and reactogenicity after the simultaneous administration of two vaccines containing novel adjuvants, among adults 65 years of age or older. They conclude that in this clinical trial, overall safety findings were similar whether patients received simultaneous doses of the two adjuvanted vaccines (Shingrix and Fluad Quadrivalent) or simultaneous doses of Shingrix (adjuvanted) and Fluzone High-Dose Quadrivalent (a nonadjuvanted high-dose vaccine). From a safety standpoint, this study supports the simultaneous administration of the two adjuvated vaccines (Shingrix and Fluad) among older adults.1In Canada, the 2024–2025 National Advisory Committee on Immunization (NACI) guidance document recommends the preferential use of high-dose inactivated influenza vaccine (Fluzone High-Dose Quadrivalent), adjuvanted inactivated influenza vaccine (Fluad) or recombinant influenza vaccine (Supemtek, a quadrivalent unadjuvanted vaccine) over other influenza vaccines for adults 65 years of age or older.2,3 NACI points out that adjuvanted recombinant zoster vaccine (Shingrix) has been shown to be safe and effective when given concurrently with unadjuvanted, standard-dose influenza vaccines. However, no studies had yet been conducted to assess the concurrent administration of Shingrix with adjuvanted influenza vaccine or high-dose influenza vaccine. NACI states that it is not known how the adjuvants in Shingrix and Fluad might interact when these vaccines are given concurrently.3 The new U.S. study results suggest that from a safety perspective, administering Shingrix with Fluad produces similar adverse events as administering Shingrix with Fluzone High-Dose Quadrivalent; both combinations are acceptable options for vaccine delivery to older adults.1 References:Schmader KE, Walter EB, Talaat KR, et al. Safety of simultaneous vaccination with adjuvanted zoster vaccine and adjuvanted influenza vaccine. A randomized clinical trial. JAMA Network Open. 2024;7(10):e2440817. (accessed October 29, 2024).National Advisory Committee on Immunization (NACI). An Advisory Committee Statement (ACS). Statement on seasonal influenza vaccine for 2024–2025. (accessed October 29, 2024).National Advisory Committee on Immunization (NACI). An Advisory Committee Statement (ACS). Supplemental guidance on influenza vaccination in adults 65 years of age and older. (accessed October 29, 2024).

Safety of simultaneous administration of adjuvanted zoster vaccine and adjuvanted flu vaccine

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