Department of Health and Human Services Announces Removal of Thimerosal from All US Flu Vaccines

On July 23, 2025, HHS secretary Robert F. Kennedy, Jr accepted a recommendation from the CDC’s Advisory Committee on Immunization Practices (ACIP) to remove thimerosal (sodium ethylmercurithiosalicylate), a mercury-based preservative, from all influenza vaccines distributed in the United States—despite decades of research showing no evidence of harm. The decision comes amid continued and growing action against vaccines, which further fuels public skepticism and mistrust in vaccination.¹

Mobile phone with logo of American Department of Health and Human Services | Image Credit: © Timon - stock.adobe.com

“After more than 2 decades of delay, this action fulfills a long-overdue promise to protect our most vulnerable populations from unnecessary mercury exposure,” RFK said in an official statement from the HHS. “Injecting any amount of mercury into children when safe, mercury-free alternatives exist defies common sense and public health responsibility. Today, we put safety first.”¹

The removal of thimerosal was initially presented by ACIP, who voted 5:1:1 at a meeting that took place in Atlanta on June 25, 2025, and June 26, 2025. According to reporting from The Guardian, the committee—comprised of members selected by RFK—voted “in favor of removing thimerosal…after a controversial presentation from Lyn Redwood, a former leader of World Mercury Project, the predecessor to Kennedy’s group Children’s Health Defense, itself a prolific anti-vaccine campaign group.”²

The announcement raises concerns among health experts while conversely empowering the anti-vaccine movement.

Thimerosal is an ethylmercury-based preservative that has been used in vaccines and drugs in the US since the 1930s and has been a topic of scrutiny since 1999. Growing vaccine hesitancy and antivaccine sentiment have persisted since the COVID-19 pandemic. Thimerosal is the latest target in a broader push by federal agencies to address public concern over vaccine ingredients, despite decades of evidence supporting its safety.^3,4

Despite its status as a mercury-based preservative, thimerosal is not comprised of the same mercury commonly found in certain fish. Mercury is comprised of 2 types: methylmercury and ethylmercury. Methylmercury is what is found in fish and can be toxic at high levels of exposure. Thimerosal is made of ethylmercury, the less toxic type of mercury that clears from the human body more quickly than methylmercury, thereby reducing harm. ^3,4

Efforts to reduce and eliminate thimerosal in vaccines began in 1999 when the American Academy of Pediatrics (AAP), the US Public Health Service, and vaccine manufacturers came to a joint agreement that thimerosal should be removed as soon as possible. Following in 2001, thimerosal was removed from all routine childhood vaccines.^1,2

Notably, the AAP has since rejected their initial claims about thimerosal. In a statement from June 2025, the AAP stated that “extensive research proves that thimerosal is a safe ingredient in vaccines, and it does not cause neurological problems or autism” and that “banning vaccine ingredients without solid scientific reasons sets a dangerous precedent and ultimately makes children less safe.” Their statement also notes that autism rates actually rose following the removal of thimerosal, suggesting there is no positive correlation between the two.^5,6

These changes are expected to take place in the 2025 to 2026 flu season, and other recommendations by the committee in June are under review.¹

“With the US now removing mercury from all vaccines, we urge global health authorities to follow this prudent example for the protection of children worldwide,” RFK said in the official statement.¹

The dissemination of misinformation is more crucial than ever as large, sweeping changes are made to vaccine policy and public health guidance. Pharmacists are uniquely positioned on the frontline of health care with the ability to properly inform patients about vaccines and assist them in vaccine decision-making.

“It’s really important for pharmacists to understand what type of information their patients are consuming,” Adam James, PharmD, told Pharmacy Times^® in an interview. “Sometimes, it helps to bring up vaccine ingredients, talk about vaccine safety, and highlight the different products available. For example, if thimerosal is a concern, we can clarify that almost every vaccine we administer in pharmacies is a single-dose, prefilled syringe—meaning it doesn’t contain thimerosal. Being transparent and proactive helps build trust and can counteract misinformation from other sources.”⁷

REFERENCES

1. HHS adopts ACIP recommendation to remove thimerosal from all U.S. influenza vaccines. US Department of Health and Human Services. July 23, 2025. Accessed July 24, 2025. https://www.hhs.gov/press-room/thimerosal-mercury-removed-from-us-flu-vaccines-acip.html

2. Glenza J. RFK Jr to remove preservative thimerosal from all US vaccines. The Guardian. July 23, 2025. Accessed July 24, 2025. https://www.theguardian.com/us-news/2025/jul/23/rfk-jr-thimerosal-vaccines

3. Thimerosal and vaccines. CDC. December 19, 2024. Accessed July 24, 2025. https://www.cdc.gov/vaccine-safety/about/thimerosal.html

4. Halpern L. Thimerosal reenters public debate as ACIP scrutinizes use in influenza vaccines. Pharmacy Times. June 27, 2025. Accessed July 24, 2025. https://www.pharmacytimes.com/view/thimerosal-reenters-public-debate-as-acip-scrutinizes-use-in-influenza-vaccines

5. Fact checked: Extensive research shows thimerosal is safe. American Academy of Pediatrics. July 15, 2025. Accessed July 24, 2025. https://www.aap.org/en/news-room/fact-checked/fact-checked-extensive-research-shows-thimerosal-is-safe/?srsltid=AfmBOor6UbOu4zlh-DXV3ivWtNLkPfQ9H_iOnZf_aArhyUYzANx6yWi-

6. Schechter R, Grether J. Continuing increases in autism reported to California's Developmental Services System. JAMA Psychiatry. January 2008. Accessed July 24, 2025. doi:10.1001/archgenpsychiatry.2007.1

7. James A, Altman C, Halpern L. Pharmacists can tackle thimerosal misinformation through education, empathy, and transparency. Pharmacy Times. July 23, 2025. Accessed July 24, 2025. https://www.pharmacytimes.com/view/pharmacists-can-tackle-thimerosal-misinformation-through-education-empathy-and-transparency