Covid 19: Dr Antony Fauci says vaccines protect against severe disease, don't work 'overly well' at stopping infection

White House chief medical adviser Dr Anthony Fauci says Covid vaccines help protect people from needing hospitalisation - or dying - with Covid even if they do not work "overly well" against stopping people from getting infected.

Fauci - the face of the pandemic in the US - fully recommended getting vaccinated as jabs protect against severe disease.

"One of the things that's clear from the data [is] that even though vaccines - because of the high degree of transmissibility of this virus - don't protect overly well against infection, they protect quite well against severe disease leading to hospitalisation and death," he told Fox News.

"And I believe that's the reason why at my age, being vaccinated and boosted, even though it didn't protect me against infection, I feel confident that it made a major role in protecting me from progressing to severe disease.

"And that's very likely why I had a relatively mild course.

"So my message to people who seem confused because people who are vaccinated get infected - the answer is if you weren't vaccinated, the likelihood [is] you would have had [a] more severe course than you did have when you were vaccinated."

The efficacy of Covid vaccines has been called into question in recent weeks as new variants spread around the world.

New subvariants of the Omicron strain appear to be able to evade vaccines, leading to an explosion of cases - and more hospitalisations.

There have been calls for the return of social distancing and the enforced wearing of face masks to reduce transmission of the disease.

World Health Organisation chief Tedros Adhanom Ghebreyesus has backed calls for some Covid measures to return, warning that the virus is running free.

He said he was worried that case numbers were shooting up, putting more strain on health systems and workers.

The number of Covid cases reported to the WHO increased 30 per cent in the past two weeks, driven by sub-variants of the Omicron strain and the lifting of control measures.

"New waves of the virus demonstrate again that Covid-19 is nowhere near over. As the virus pushes at us, we must push back," he said.

He told a news conference that as transmission increases, governments must also deploy tried-and-tested measures like mask-wearing and improving ventilation.