U.S. ultimatum to vaccine group: No more funds unless you stop using thimerosal

A health worker in Mali prepares a vaccination that protects against five diseases: diptheria, tetanus, meningitis, pertussis and hepatitis B. In vials like this one, which contains multiple doses, thimerosal is used as a preservative that can prevent contamination.

This mercury-containing compound, used as a vaccine preservative, is commonly used in lower-income countries — and deemed safe. The U.S. is now demanding that Gavi, the Vaccine Alliance stop using it.

(Image credit: Jürgen Bätz/Picture Alliance)