Which 2025 inactivated influenza vaccine brands contained thimerosal versus thimerosal-free formulations?

1. What regulators recommended — a clear steer away from thimerosal‑containing presentations

The Advisory Committee on Immunization Practices (ACIP) issued a new recommendation in June 2025 that children ≤18 years, pregnant women, and all adults should receive only single‑dose influenza vaccines that are free of thimerosal as a preservative for the 2025–26 season; this recommendation is published in CDC’s MMWR guidance ^[2]. CDC and FDA pages also explain that single‑dose presentations and the nasal spray are generally thimerosal‑free while multi‑dose vials use thimerosal to prevent contamination ^{[1] [4]}.

2. How manufacturers packaged vaccines — single‑dose predominates, multi‑dose still exists

Manufacturer product information and clinical reference tables for the 2025–26 season list the common U.S. influenza brands (Afluria, Fluad, Fluarix, Flucelvax, FluLaval, Fluzone, Fluzone High‑Dose, Flublok, FluMist) and indicate that most of these are supplied in single‑dose syringes or single‑dose vials that do not contain thimerosal; multi‑dose vial availability with thimerosal varies by manufacturer and had historically accounted for a small share of supply ^{[5] [6] [7] [8]}. Seqirus’s Fluad prefilled‑syringe labeling explicitly notes “no preservatives” / “thimerosal‑free” for its 2025–26 prefilled syringe product ^[8].

3. How much of the supply was thimerosal‑free — CDC’s supply projections

CDC projected up to about 154 million doses for 2025–26 and stated that most of the projected influenza vaccine supply produced that season did not contain thimerosal as a preservative; CDC also noted multi‑dose vials containing thimerosal had historically been a small proportion of total supply ^[3]. Independent clinical compendia and professional references for 2025–26 likewise describe single‑dose, thimerosal‑free formulations as the dominant presentation ^[5].

4. Which specific brands had thimerosal‑containing vs thimerosal‑free presentations

Available sources indicate that for many brand names both presentation types historically existed: single‑dose prefilled syringes and single‑dose vials (thimerosal‑free) versus multi‑dose vials (thimerosal‑containing), with availability of the multi‑dose option varying by manufacturer ^{[7] [9]}. Product pages and supplier listings for 2025–26 explicitly label prefilled syringes (e.g., Fluad prefilled syringe) as thimerosal‑free ^[8]. However, a comprehensive, brand‑by‑brand public table in these sources showing every manufacturer’s 2025 portfolio broken down by presentation is not provided in the current reporting; in short, brands commonly offered thimerosal‑free single‑dose presentations and some manufacturers also made multi‑dose vials with thimerosal available ^{[7] [1]}.

5. Safety, debate, and competing viewpoints

CDC and FDA materials state there is no evidence that the low doses of thimerosal used in vaccines cause harm, and they describe thimerosal’s long history as a preservative in multi‑dose vials while noting single‑dose options are available ^{[10] [4] [1]}. ACIP’s recommendation to prefer thimerosal‑free single‑dose presentations was approved without GRADE/EtR analysis and was described in MMWR as an explicit programmatic preference rather than a new safety finding; some public health and global organizations (e.g., AAP, WHO, and others cited in clinical compendia) have continued to support use of multidose vials containing thimerosal when necessary to expand access, reflecting a practical tradeoff between preservative use and vaccine campaign logistics ^{[5] [2] [3]}.

6. Practical takeaway for clinicians and patients

If you or your clinic want an influenza shot without thimerosal in 2025–26, request a single‑dose presentation or a prefilled syringe; CDC guidance and product labeling identify those formulations as thimerosal‑free and ACIP recommended their use broadly for the season ^{[1] [8] [2]}. If only multi‑dose vials are available, recognize that CDC and FDA describe the preservative as commonly used for multi‑dose vials and that historically such vials represented a small portion of supply ^{[4] [3]}.

Limitations: public documentation in the supplied sources confirms the general pattern (single‑dose = thimerosal‑free; multi‑dose = thimerosal) and CDC’s ACIP recommendation, but they do not supply a single authoritative, row‑by‑row table in these results listing every 2025 product presentation and which exact NDCs or lots contained thimerosal; product pages and clinical compendia must be consulted for brand‑and‑presentation specifics at the point of care ^{[8] [5] [7]}.