Which manufacturers and specific 2025–2026 flu vaccine formulations are available in single‑dose prefilled syringes versus multi‑dose vials?
Executive summary
The 2025–2026 U.S. influenza season features a clear policy tilt: public-health advisers and CDC/ACIP recommend using single‑dose formulations that are free of thimerosal for children, pregnant people, and adults, and several manufacturers do offer prefilled‑syringe (PFS) presentations that meet that standard [1] [2]. While multi‑dose vials (MDVs) containing thimerosal still exist for some products, their availability varies by manufacturer and they are explicitly not recommended for routine use this season [2] [3].
1. What regulators decided and why it matters
The Advisory Committee on Immunization Practices and CDC adopted a new recommendation that children ≤18 years, pregnant women, and all adults should receive influenza vaccines only in single‑dose, thimerosal‑free formulations for 2025–2026, a policy that pushes providers toward prefilled syringes and single‑dose vials and away from multi‑dose vials that contain the mercury‑derived preservative [1] [2].
2. Manufacturer-level specifics that are documented in product labeling
Manufacturer product information and FDA/CDC documents confirm some concrete packaging details: Seqirus’s FLUCELVAX is offered as 0.5 mL prefilled syringes that contain no preservative and also as 5 mL multi‑dose vials that do contain thimerosal [4]. Sanofi’s Fluzone materials indicate that single‑dose prefilled syringes and single‑dose vials are manufactured and formulated without thimerosal for approved presentations [5]. These are explicit manufacturer statements in package inserts and FDA documents rather than inference [4] [5].
3. Products with single‑dose PFS presentations frequently available
Several of the season’s approved vaccines are described by CDC and state health resources as having single‑dose, thimerosal‑free PFS options; ACIP’s season overview lists multiple IIV3, RIV3 and LAIV3 formulations expected on the market and emphasizes single‑dose, thimerosal‑free presentations as the ACIP recommendation [1]. Local public‑health communications (for example, New York City) reiterate that recommended seasonal vaccination is with single‑dose, thimerosal‑free formulations and note Afluria and other brands’ PFS presentations where applicable [6] [7].
4. Multi‑dose vials still exist but are limited and not recommended
Although MDVs containing thimerosal have historically accounted for a small share of supply and remain available from some manufacturers, CDC and ACIP state they are not recommended this season; guidance and state documents warn that MDV use may be restricted (for example, children <3 years) or require informed consent if no alternative is available [2] [7] [8]. Clinical and procurement guidance make clear that availability of MDV formats “is expected to vary by manufacturer,” and professional groups note that some global bodies still support MDV use in certain programs even as ACIP cautions against it domestically [3] [9].
5. What is documented versus what remains uncertain
Product inserts and CDC material allow definitive statements about specific products documented in those sources—FLUCELVAX PFS/no preservative and MDV/with thimerosal [4], Fluzone single‑dose PFS and single‑dose vial being thimerosal‑free [5], and the availability of Afluria 0.5 mL PFS with MDV formulations not recommended for some pediatric ages [7] [1]. However, a comprehensive, source‑verified roster that maps every manufacturer and every vaccine formulation to “PFS vs MDV” for every lot and distribution channel is not present in the materials provided; CDC supply projections and NDC crosswalks should be consulted for an up‑to‑date, complete matrix [2] [8].
6. Practical takeaway for providers and procurement officers
The operational effect is direct: clinicians and clinics should plan to prioritize ordering single‑dose, thimerosal‑free prefilled syringes or single‑dose vials where possible and treat multi‑dose vials containing thimerosal as a contingency product with age‑ and consent‑related limits; vaccine ordering and coding documents from CDC/local health departments can identify which NDCs/brands in a shipment are PFS versus MDV [1] [8] [2].