Context:

Lyn Redwood, formerly of the anti-vaccine group Children's Health Defense, is set to present on thimerosal in flu vaccines at a CDC vaccine advisers meeting, raising concerns due to past debunked claims linking thimerosal to autism. Thimerosal, a preservative containing ethylmercury, was removed from most vaccines due to mercury concerns, though studies have shown it is not linked to neurodevelopmental issues. Robert F. Kennedy Jr.'s recent changes to the Advisory Committee on Immunization Practices, including replacing all 17 former members, have stirred public health community apprehension. While most modern flu vaccines for children don't contain thimerosal, some multi-dose vials still do, prompting a vote and discussion on the matter. Redwood's involvement with vaccine safety issues is long-standing, and her upcoming presentation has drawn attention given her controversial history and the current advisory committee's composition.

Dive Deeper:

• Lyn Redwood, who has a history with the anti-vaccine group Children's Health Defense, is scheduled to present to the CDC's new vaccine advisory panel about thimerosal in flu vaccines, despite its past removal from most vaccines due to mercury content concerns.

• Thimerosal, containing ethylmercury, is a preservative used in some vaccines to prevent microbial growth. Although it was removed from most vaccines decades ago, subsequent studies have shown no link between thimerosal and neurodevelopmental issues like autism.

• The recent restructuring of the CDC's Advisory Committee on Immunization Practices by Robert F. Kennedy Jr., who dismissed all former members and installed new ones, has caused unease in the public health sector, particularly with the inclusion of the thimerosal topic on the agenda.

• Most flu vaccines for children are now provided in single-dose vials or pre-filled syringes, which do not contain thimerosal. However, some multi-dose vials, accounting for about 4% of flu vaccines in the US, still include it, prompting a vote at the CDC meeting.

• Redwood's presentation is atypical as presenters usually come from ACIP working groups with extensive evidence review experience. Her history with advocating against thimerosal in vaccines, despite numerous studies showing no harm at low doses, has brought her involvement into question.