The US government has frozen funds to Gavi, the global vaccine alliance, until it commits to a plan to phase out the preservative thimerosal from all the vaccines it distributes.

The US demand, first reported by Reuters, is linked to the unproven belief held by US Health and Human Services (HHS) Secretary Robert F Kennedy Jr and allies that thimerosal, which contains mercury, is linked to autism.

However, even the US Food and Drug Administration has pronounced that “thimerosal has been the subject of numerous studies and has a long record of safe and effective use preventing bacterial and fungal contamination of vaccines, with no ill effects established other than minor local reactions at the site of injection.” 

The FDA also notes that a vaccine with 0.01% thimerosal as a preservative contains “roughly the same amount of elemental mercury [as] contained in a three-ounce can of tuna fish”.

Around 14% of Gavi’s vaccines contain thimerosal, which is used in some multi-dose vials to destroy any bacteria and fungi that may enter a vial each time a new dose is drawn.

Multi-dose vaccines are used in many low- and middle-income countries as they are cheaper.

Affected Gavi vaccines include the five-in-one pentavalent vaccine (Diphtheria, Pertussis , Tetanus, Hepatitis B and Haemophilus influenzae type b), the Diphtheria, Pertussis and Tetanus (DPT) vaccine, Tetanus-Reduced Diphtheria (Td), Hepatitis B, Meningococcal A Conjugate (MenA) and Pneumococcal Conjugate Vaccine (PCV).

Most US vaccines do not contain thimerosal, while it is seldom found in Europe, which relies mainly on single-dose vaccines.

Scientific consensus

“We received a request from the US government to remove thimerosal from our portfolio. We remain in contact on this subject,” a Gavi spokesperson told Health Policy Watch.

“While we very much hope to find a pathway to welcoming the US back as a donor, any decision related to Gavi’s portfolio would require a decision by Gavi’s Board and input from preceding governance committees, which will be guided by scientific consensus.”

Hanging in the balance is some $300 million already allocated by the Biden administration but not yet paid, as well as any new funds.

All Gavi-supported vaccines have to be recommended by the World Health Organisation’s (WHO) Strategic Advisory Group of Experts (SAGE), an independent body that examines all available scientific evidence and issues global guidance on the use of vaccines.  

In addition, each manufacturing site where Gavi-supported vaccines are produced must be approved or “pre-qualified” by WHO.

Gavi-supported vaccines must also be recommended by the National Immunisation Technical Advisory Group (NITAG) in each country where they are being used. Most Gavi-supported countries also require vaccines to be approved by their own National Regulatory Authorities (NRAs), in addition to WHO approvals.

In June last year, Kennedy told Gavi that the US would withhold funds until it “re-earned the public trust”, claiming that it had “ignored vaccine safety”. The US recently lost its seat on the Gavi board as it has failed to pledge any funds to it.

Image Credits: Twitter: @WHOAFRO, WHO.