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, they decided consultation with a medical professional would better guide individuals' choices.

The federal government already stopped recommending Covid-19 vaccines for healthy pregnant women and children in May.

In a heated debate, some allies of Kennedy questioned the vaccine's effectiveness in preventing serious infections, while others pointed to data supporting its use.

Confusion arose regarding the MMRV vaccine; previously voted down for children under four, the panel endorsed separate shots for measles, mumps, rubella, and varicella.

The American Medical Association expressed concern over the new MMRV recommendations, describing them as potentially confusing for parents.

Additionally, a vote on whether infants of hepatitis B negative mothers should receive the vaccine at birth has been delayed, with ACIP casting doubts over the vaccine's necessity despite scientific consensus on its effectiveness.

Robert F Kennedy Jr's approach to vaccinations has drawn criticism, leading to staff resignations amid policy disputes during his tenure as health secretary.