Several leading medical organisations have filed a lawsuit against the U.S. Health Secretary Robert F. Kennedy Jr. and the Department of Health and Human Services on Monday, arguing that current policies on COVID-19 vaccines pose an imminent threat to public health.

The plaintiffs, including the American Academy of Paediatrics, the American College of Physicians, the American Public Health Association, and the Infectious Diseases Society of America, have asked the court to vacate Kennedy's recent directive removing the COVID-19 vaccine from the Centres for Disease Control and Prevention's childhood and pregnant women immunisation schedules.

The lawsuit accuses Kennedy of working "to dismantle the longstanding, Congressionally-authorised, science- and evidence-based vaccine infrastructure that has prevented the deaths of untold millions of Americans."

Representatives for HHS did not immediately respond to a request for comment.

Lead counsel for the plaintiffs, Richard Hughes, a partner at law firm Epstein Becker Green, said he hopes to expedite the case, with a hearing in the next few weeks and a permanent order in the case entered by September.

Kennedy, who for decades has sown doubt about the safety of vaccines contrary to evidence and research by scientists, is head of the department that oversees the CDC. He said in May that the CDC would remove the COVID shot from vaccination schedules for healthy children and healthy pregnant women.

The complainants alleged that such "baseless and uninformed policy" decisions place critical populations at "grave and immediate risk" of preventable illness, long-term harm, or death.

HHS' changes to the COVID vaccine recommendations have led pregnant women and parents to question the value of other recommended vaccines, representatives of the medical societies said.

"We're hearing from paediatricians all over the country that parents are having significant concerns about every single vaccine," Susan Kressly, president of the American Academy of Paediatrics, said at a press conference.

In addition to the new directive on COVID vaccines, Kennedy fired all 17 members of the CDC's Advisory Committee on Immunisation Practices, the independent panel of experts that advises the agency on vaccine policy, and replaced them with seven new members, including several who have advocated against vaccines.

The lawsuit doesn't address Kennedy's overhaul of that committee. But Hughes told reporters that he expects the new members will take action against other vaccines, and the groups plan to amend their complaint when that happens.