US health secretary Robert F Kennedy Jr on Wednesday signed a recommendation to eliminate thimerosal from all influenza vaccines.Thimerosal, a mercury-based preservative used in vaccines since World War II, has long been criticised by anti-vaccine groups. Kennedy, a known sceptic of vaccine safety standards, said, “After more than two decades of delay, this action fulfills a long-overdue promise to protect our most vulnerable populations from unnecessary mercury exposure.” The recommendation came from the advisory committee on immunisation practices (ACIP), following a 26 June meeting where the majority voted against allowing any flu vaccines to contain thimerosal. The proposal was introduced by Lyn Redwood, former head of children’s health defence, an anti-vaccine group Kennedy himself founded.However, not everyone on the panel agreed. Dr Cody Meissner was the only ACIP member to oppose the decision. He argued there is no scientific evidence that thimerosal caused harm and warned that banning it could increase costs and reduce vaccine access, especially in countries that still rely on preserved vaccine stock.According to the centers for disease control and prevention, nearly 96% of flu vaccines in the US are already thimerosal-free for the 2024–2025 season. But FDA continues to back its safety, citing decades of global research. FDA states that “a robust body of peer-reviewed, scientific studies conducted in the United States and countries around the world support the safety of thimerosal-containing vaccines.”While improved manufacturing has made preservatives less necessary, experts say a full ban could hurt international vaccine programmes that still depend on multi-dose vials containing thimerosal.