Gavi works to expand access to vaccines for children in some of the world’s poorest countries. Health experts say the move could have deadly consequences.

Lyn Redwood, a nurse who served for years as president of Children’s Health Defense, an anti-vaccine group founded by Kennedy, will be joining the CDC’s Immunization Safety Office, multiple health officials told The Washington Post, CBS News, and ABC News.

The preservative thimerosal has been removed from all but a few vaccines, and studies have confirmed no link to neurodevelopmental issues including autism. So public health experts were puzzled when it appeared on the agenda for this week’s meeting of outside vaccine advisers to the US Centers for Disease Control and Prevention.