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

For RFK Jr. and his antivax supporters and associates, aluminum adjuvants in some required children’s vaccines appear to be the next target.

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.

A nonprofit anti-vaccine group founded by Robert F. Kennedy Jr. is suing him, in his capacity as secretary of the US Department of Health and Human Services, for failing to establish a task force to promote the development of safer childhood vaccines.

The Wisconsin DHS added a requirement for the 2024-25 school year for the Meningococcal conjugate vaccine (MenACWY) by seventh grade, and a booster by 12th grade. Meningococcal disease is a rare, but serious disease that can be fatal in 10% to 15% of people who get it.

The CDC says there is no evidence of harm from mercury-based thimerosal.

Federal guidelines no longer recommend flu vaccines containing a preservative, used in a small percentage of vaccines, that has been falsely linked to autism.

The health secretary has made many inaccurate statements about vaccines. But the science is clear that vaccines have dramatically reduced childhood illness, disability and death.