Covid vaccine

The vaccine was approved in India in January while the third phase of clinical trials was still under way, sparking some concern and criticism.

Bharat Biotech, which makes the vaccine, has since published data suggesting 78 percent efficacy.

The WHO said in a tweet it believed the benefits far outweighed the risks.

Some experts had pointed to a fast-track approval and incomplete data, but the firm's chairman, Dr Krishna Ella, said the vaccine was "200% safe".

It has been taken to a central hub at an undisclosed location, and will now be distributed to hospital vaccination centres around the UK.

The UK has ordered 40 million doses - enough to vaccinate 20 million people.

England's deputy chief medical officer said the first wave of vaccinations could prevent up to 99% of Covid-19 hospital admissions and deaths.

Speaking to BBC News, Prof Jonathan Van-Tam said that would be possible if everyone on the first priority list took the vaccine and it was highly effective.