Expert warns RFK Jr has just made the most dangerous public health decision he's seen

America's vaccine-sceptic health secretary has announced $500m (£375.8m) worth of cuts to their development in the country.

The US health department is cancelling contracts and pulling funding for jabs to fight viruses like COVID-19 and the flu, it was announced on Tuesday.

Robert F Kennedy Jr, known as RFK Jr, said 22 projects developing mRNA vaccines will be halted. It is the latest in a series of decisions to reduce US vaccine programmes.

Read more: Who is Donald Trump's health chief?

The health secretary has fired the panel that makes vaccine recommendations, reduced recommendations for COVID-19 shots, and refused to endorse vaccines despite a worsening measles outbreak.

RFK Jr claims the US will now prioritise "safer, broader vaccine strategies, like whole-virus vaccines and novel platforms that don't collapse when viruses mutate".

Responding to the announcement of cuts, Mike Osterholm, a University of Minnesota expert on infectious diseases and pandemic preparations, said: "I don't think I've seen a more dangerous decision in public health in my 50 years in the business."

Dr Paul Offit, a vaccine expert at Children's Hospital of Philadelphia, said RFK Jr's move was short-sighted and that mRNA vaccines "certainly saved millions of lives", including during the pandemic.

MRNA vaccines work by delivering a snippet of genetic code into the body that triggers an immune response, rather than introducing a real version of the virus.

According to the UK Health Security Agency, the "leading advantage of mRNA vaccines is that they can be designed and produced more quickly than traditional vaccines".

Moderna, which was studying a combo mRNA shot that can tackle COVID and flu for the US health department, previously said it believed mRNA could speed up production of flu jabs compared with traditional vaccines.

Read more from Sky News:Harry criticises report into charityReeves told to find 'substantial' tax rises

Scientists are also exploring how mRNA could be used in cancer immunotherapies and in other illnesses.

At the White House earlier this year, billionaire tech entrepreneur Larry Ellison praised mRNA for its potential to treat cancer.

RFK Jr touts 'effective' alternative

The health department said the abandoned mRNA projects signal a "shift in vaccine development priorities."

"Let me be absolutely clear, HHS supports safe, effective vaccines for every American who wants them," Mr Kennedy said in a statement.

Later, he said work is underway on an alternative - a "universal vaccine" that mimics "natural immunity".

"It could be effective - we believe it's going to be effective - against not only coronaviruses, but also flu," he said.