Decisions from the U.S. Preventative Services Task Force impact millions of people’s access to preventative care for cancer, infectious diseases and mental health

The mercury-based ingredient has prompted concerns from some organizations, although the CDC has said there is no evidence it causes harm.

This week, Children’s Health Defense backed a lawsuit against its founder, Health and Human Services Secretary Robert F. Kennedy Jr., alleging he “has failed” to comply with federal law by not creating a federal task force seeking the development of “safer” childhood vaccines.

Flu shots that have more than one dose of vaccine contain thimerosal; other versions don’t have it. HHS said Wednesday that vaccine makers have said they have the capacity to replace the shots that do contain thimerosal so that vaccine supplies aren’t interrupted.

Vaccines are one of the greatest public health successes of modern medicine. From smallpox to polio to measles, vaccines have saved millions of lives, protected entire generations from disability and death, and fortified our communities against the spread of infectious disease. But this foundation of disease prevention is now under attack.

Health Secretary Robert F. Kennedy Jr. recently announced a change to the Centers for Disease Control and Prevention's vaccine schedule that he says reflects a new approach to public health and personal choice.

Kennedy Jr., the nation’s health secretary, sparked fierce criticism earlier this year when he pledged to determine what causes autism by September — a deadline deemed wildly unrealistic by many longtime researchers.