LONDON, January 29, 2026, 17:20 GMT
- The U.S. ties future Gavi funding to a strategy for phasing out vaccines that contain thimerosal
- Gavi insists that any portfolio changes require board approval and must align with scientific consensus
- Experts caution that a rapid move away from multi-dose vials might drive up costs and throw immunisation campaigns off track
The United States has warned Gavi, the Vaccine Alliance, that it will withhold new funding unless the group begins phasing out vaccines containing thimerosal, a mercury-based preservative, according to a U.S. health official and a Gavi spokesperson. This demand targets a pending $300 million pledge as well as any future financial support, the official said. 1
This dispute is crucial since Gavi supplies and supports vaccine delivery in lower-income nations, where multi-dose vials maximize budgets and ease staffing demands. Thimerosal, primarily found in those vials, preserves dose stability. Plus, these vials cost less and are easier to distribute than single-dose injections.
This comes amid a broader U.S. shake-up of vaccine policy that’s now echoing beyond its borders. Health Secretary Robert F. Kennedy Jr. claims thimerosal is tied to autism, even though decades of research and global health organizations have found no harm at the levels used.
An official from the U.S. Department of Health and Human Services stated that Washington will “withhold future new funding” until Gavi creates and starts implementing a plan to phase out thimerosal-containing vaccines. The official didn’t specify when this request was made and noted that Gavi has yet to present a phase-out plan.
Gavi confirmed it was asked to remove thimerosal from its vaccine lineup but emphasized that such a step would require approval from its board and advisory committees. A spokesperson added that decisions would follow scientific consensus and that the organization continues to liaise with the U.S. government.
Thimerosal is included in certain vaccine vials to prevent contamination as the rubber stopper is pierced multiple times. While wealthier nations have mostly phased out the preservative—favoring single-dose packaging—it’s not banned. In fact, the U.S. took steps last summer to phase out thimerosal from flu vaccines, which made up roughly 5% of all doses.
The United States once accounted for roughly 13% of Gavi’s funding, but last June, Kennedy slashed $300 million in annual aid to the alliance. Since its 2000 launch alongside partners like the World Health Organization, UNICEF, the World Bank, and the Gates Foundation, Gavi has begun trimming expenses amid shrinking donor contributions.
Gavin Yamey, a Duke University professor specializing in global health and public policy, warned that a swift shift would disrupt everything from manufacturing to delivery. “It would cause enormous upheaval,” he said, emphasizing that multi-dose vials play a key role in vaccination drives in low-resource areas. 2
U.S. officials argue that phasing out thimerosal would bring the poorest countries’ practices in line with those of the U.S., Canada, and Europe. They’ve also cautioned Gavi that funding from the U.S. International Development Finance Corporation might be put on hold. Thimerosal contains ethylmercury, which differs from methylmercury that builds up in the body, and Kennedy has pointed out that “safe, mercury-free alternatives exist.” 3
The timeline, costs, and supply risks remain unclear, and switching vial formats often takes years rather than weeks. If Gavi’s board pushes back or manufacturers can’t adapt swiftly, the funding deadlock might drag on — with vaccine drives in poorer countries likely to suffer first.
