LONDON, January 29, 2026, 17:20 GMT
- U.S. links future Gavi funding to a plan to phase out thimerosal-containing vaccines
- Gavi says portfolio changes need board approval and must follow scientific consensus
- Experts warn a quick shift away from multi-dose vials could raise costs and disrupt immunisation drives
The United States has told Gavi, the Vaccine Alliance, it will hold back new funding unless the group starts phasing out vaccines that contain thimerosal, a mercury-based preservative, a U.S. health official and a Gavi spokesperson said. The condition would apply to an outstanding $300 million pledge and to any future support, the official added. Reuters
The clash matters because Gavi buys and helps deliver vaccines for lower-income countries, where multi-dose vials help stretch budgets and staff. Thimerosal is used mainly in those vials to keep doses stable, and they are cheaper and simpler to distribute than single-dose shots.
It also lands in the middle of a wider U.S. shake-up of vaccine policy, now spilling beyond U.S. borders. Health Secretary Robert F. Kennedy Jr. has argued thimerosal is linked to autism, despite decades of research that global health bodies say has not shown harm at the levels used.
An official at the U.S. Department of Health and Human Services said Washington will “withhold future new funding” until Gavi develops and begins a plan to remove thimerosal-containing vaccines. The official did not say when the request was made and said Gavi had not yet set out a phase-out plan.
Gavi confirmed it had been asked to drop thimerosal from its vaccine portfolio, but said any move would need sign-off from its board and advisory committees. A spokesperson said decisions would be guided by scientific consensus and that the group remained in contact with the U.S. government.
Thimerosal is added to some vaccine vials to stop contamination when the rubber stopper is pierced repeatedly. The preservative has largely been phased out in rich countries, where vaccines are usually packaged for single use, though it is not banned; the United States moved last summer to stop using thimerosal-containing flu shots, which accounted for about 5% of doses.
The United States used to provide about 13% of Gavi’s funding, and Kennedy cut $300 million in annual support for the alliance last June. Gavi, launched in 2000 with partners including the World Health Organization, UNICEF, the World Bank and the Gates Foundation, has started cost-cutting as donor money tightens.
Gavin Yamey, a professor of global health and public policy at Duke University, said a rapid change would ripple from manufacturing to delivery. “It would cause enormous upheaval,” he said, noting multi-dose vials are central to campaigns in low-resource settings. Umn
U.S. officials say a phase-out would align the poorest countries more closely with U.S., Canadian and European practice and have warned Gavi that a financing line through the U.S. International Development Finance Corporation could be paused. Thimerosal contains ethylmercury — different from the methylmercury that accumulates in the body — and Kennedy has said “safe, mercury-free alternatives exist.” Pharmexec
But the timeline, costs and supply risks are murky, and changing vial formats can take years, not weeks. If Gavi’s board resists or manufacturers cannot shift quickly, the funding standoff could linger — and vaccine campaigns in poorer countries could feel it first.
