Which flu shots in 2025 do not have thimerisol
Executive summary
For the 2025–26 U.S. flu season, federal agencies recommend using only single‑dose flu vaccine formulations that are free of the preservative thimerosal; most flu doses already supplied in single‑dose syringes do not contain thimerosal and manufacturers projected ~154 million doses for 2025–26 with most thimerosal‑free [1] [2]. Multi‑dose vials that use thimerosal accounted for a very small share of vaccines in 2024–25 (about 4%) and remain an exception rather than the norm [3] [4].
1. What the official guidance says — “single‑dose only” for 2025–26
The CDC and ACIP updated guidance for the 2025–26 season recommends that children, pregnant women and adults receive seasonal influenza vaccines only in single‑dose formulations that are free of thimerosal as a preservative [1] [5]. HHS adopted the ACIP recommendation to remove thimerosal from all influenza vaccines distributed in the United States, formalizing the move away from thimerosal‑containing multi‑dose vials [6].
2. How common thimerosal‑containing doses were before the change
Even before the recommendation, thimerosal‑containing multi‑dose vials were rare: reporting shows about 4% of flu shots administered in 2024–25 contained thimerosal, and over 95% of doses were thimerosal‑free across age groups [3] [4]. Public projections for 2025–26 anticipated most of the projected 154 million doses would be thimerosal‑free [2].
3. Why single‑dose vials usually mean “no thimerosal”
Thimerosal has been used as a preservative in multi‑dose vials to prevent contamination each time a dose is withdrawn; single‑dose prefilled syringes and nasal spray vaccines are intended for one use and therefore generally do not include a preservative such as thimerosal [7] [3]. CDC materials note that most single‑dose formulations are free of thimerosal and that providers can offer thimerosal‑free vaccines if patients ask [7] [1].
4. Safety debate and competing viewpoints in the record
Health authorities including CDC, FDA and WHO have said studies do not link thimerosal in vaccines to autism or other developmental disorders; historically, thimerosal was removed from most pediatric vaccines beginning in 1999 as a confidence‑building precaution rather than because of demonstrated harm [7] [8]. Some public reporting and medical groups framed the ACIP vote as responding to long‑standing public concern and noted thimerosal’s ready safety record, while other outlets and professional groups criticized the recommendation as influenced by misinformation and warned the committee bypassed usual evidence processes [9] [10] [11].
5. Practical implications for patients and providers
For most people the change is unlikely to affect access: single‑dose, thimerosal‑free vaccines already constituted the bulk of supply and manufacturers said they do not expect disruptions while transitioning away from multi‑dose vials [1] [11]. CDC and clinician guidance continued to emphasize that influenza vaccination remains recommended for everyone 6 months and older, and that vaccines appropriate for age and risk should be used [1] [12].
6. What is not covered or remains uncertain in available reporting
Available sources do not mention detailed, binding changes to insurance reimbursement, the Vaccines for Children program logistics, or how remaining multi‑dose stocks will be handled in every state; some articles flagged those operational questions without firm answers [10] [11]. Additionally, while manufacturers projected supply and signaled minimal disruption, local availability and clinic stock practices can vary and are not fully documented in the current reporting [1] [11].
7. Bottom line and how to act if you prefer a thimerosal‑free shot
If you want to avoid thimerosal, ask your clinician or pharmacist for a single‑dose formulation; public health agencies explicitly state you can request a thimerosal‑free flu vaccine and that most available 2025–26 doses are expected to be thimerosal‑free [7] [2]. Health authorities also stress that the scientific consensus finds no proven harm from thimerosal at vaccine levels, while the new policy aims to eliminate its use in routine influenza vaccination in the U.S. [8] [7].