A key US vaccine advisory committee has voted to stop recommending all adults get the Covid-19 vaccine, which has until now been officially approved for most Americans annually since the pandemic.

The Advisory Committee on Immunization Practices (Acip) also narrowly voted against advocating prescriptions for the Covid vaccine.

In two days of meetings, Acip changed its recommendations on the combined measles, mumps, rubella, varicella (MMRV) vaccine, and delayed plans for a vote on the hepatitis B vaccine.

Health Secretary Robert F Kennedy Jr, a vaccine sceptic, fired all 17 members of the committee in June and handpicked their successors, sparking uproar in the medical community.

The panel spent Friday debating the Covid-19 vaccine, which has for the past several years been a routine recommendation, like the yearly flu jab.

Acip voted to abandon broad support for recommending the jab, including for high-risk populations like people aged over 65. Instead, it decided they could make their own decision after talking with a medical professional.

In May, the federal government stopped recommending Covid-19 vaccines for healthy pregnant women and children.

In one exchange, Kennedy's ally Dr Robert Malone argued there was no evidence that the Covid vaccine prevented serious infection. Dr Cody Meissner, once part of the Food and Drug Administration's vaccines panel, countered that there is pretty well-defined data that the jab protects against infection.

There was confusion during the debate over the MMRV vaccine. On Thursday, the panel voted against recommending the combined MMRV shot for children aged four and under but later supported two separate jabs for measles, mumps, rubella, and varicella.

The American Medical Association noted that the new MMRV recommendations leave parents confused.

The panel also delayed a vote on whether newborns whose mothers have tested negative for hepatitis B during pregnancy should automatically receive a vaccination for the liver virus.

Kennedy's management of the CDC and vaccine policies has gathered criticism, especially following such drastic committee changes and controversies regarding vaccine safety and efficacy.