The United States will only provide funding to a global vaccine group if it agrees to phase out vaccines that make use of thimerosal, a preservative that contains a form of mercury, Reuters reports.¹

Gavi, the Vaccine Alliance, is a group that describes itself as being focused on improving access to vaccines for children living in the world’s poorest countries. While the United States previously helped provide funding for the group, that changed last year when the Trump administration came into power.

In June 2025,² Reuters reported that HHS Kennedy announced that the US will no longer provide any funding to the group. According to the news outlet, Kennedy stated that he came to the decision because he believes that the group ignores safety, although he did not provide any evidence to back up this claim. Kennedy also cited the group’s recommendations for the COVID-19 vaccine.

In a statement posted to its website in response to Kennedy’s claims,³ Gavi wrote, “Gavi’s utmost concern is the health and safety of children. Any decision made by Gavi with regards to its vaccine portfolio is made in alignment with recommendations by WHO’sStrategic Advisory Group of Experts on Immunization (SAGE), a group of independent experts that reviews all available data through a rigorous, transparent, and independent process. This ensures Gavi investments are grounded in the best available science and public health priorities.”

Now, the Trump administration reportedly communicated to Gavi that any future funding will be reliant on Gavi removing any shots containing thimerosal. As of yet, the vaccine group has refused to develop a plan to do so.

Why is HHS against the use of thimerosal in vaccines?

Thimerosal is a common target of HHS Secretary Kennedy. The preservative has long been at the center of claims from anti-vaccine groups due to the fact that it contains Mercury, which these groups have suggested can cause autism. Multiple studies have disproven this theory, and the general consensus amongst the medical community is that thimerosal in vaccines does not cause autism.

In July 2025, HHS announced plans to remove thimerosal from all US influenza vaccines.⁴

In a statement issued at the time, HHS Kennedy said, “After more than two decades of delay, this action fulfills a long-overdue promise to protect our most vulnerable populations from unnecessary mercury exposure. 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.”

Thimerosal is a preservative used for vaccines with multi-dose vials that prevents bacterial contamination from repeated punctures. In 2001, the US phased out the use of a preservative, although experts say that was done out of an abundance of caution, PBS reports.⁵ Studies have consistently shown that the substance does not cause any harm in vaccines at the amounts it was used.

The connection likely comes from the fact that while thimerosal is a form of Mercury, it’s specifically ethylmercury, a substance the body is able to excrete. The toxic form of Mercury is methylmercury.

Regardless, HHS’ current leadership continues to push against the use of the substance, even within global organizations. In response to the Gavi’s refusal to draw up plans to not use vaccines with thimerosal, an HHS spokesperson told Reuters, “Until a plan for removal of thimerosal-containing vaccines is developed and the plan initiated, the United States will withhold future new funding.”

Sources

1. Exclusive: US conditions funding to global vaccine group on dropping mercury-based preservative from shots. Reuters. January 28, 2026. https://www.reuters.com/business/healthcare-pharmaceuticals/us-conditions-funding-global-vaccine-group-dropping-mercury-based-preservative-2026-01-28/
2. US to stop financial support of global vaccine alliance Gavi, health secretary says. Reuters. June 25, 2025. Accessed January 28, 2026. https://www.reuters.com/business/healthcare-pharmaceuticals/us-stop-financial-support-global-vaccine-alliance-gavi-says-health-secretary-2025-06-25/
3. Statement. Gavi. June 25, 2025. Accessed January 28, 2026. https://www.gavi.org/news/media-room/statement-response-25-june-2025
4. HHS Adopts ACIP Recommendation to Remove Thimerosal from All U.S. Influenza Vaccines. HHS. July 23, 2025. Accessed January 28, 2026. https://www.hhs.gov/press-room/thimerosal-mercury-removed-from-us-flu-vaccines-acip.html
5. What to know about thimerosal, vaccine preservative from bygone flu-shot debate. PBS. June 26, 2025. Accessed January 28, 2026. https://www.pbs.org/newshour/health/what-to-know-about-thimerosal-vaccine-preservative-from-bygone-flu-shot-debate