The World Health Organization said Tuesday it is in discussions with Pfizer and Moderna about possibly including their high-tech coronavirus vaccines among early jabs for poor countries at affordable prices.

The WHO-backed Covax facility, created to ensure equitable access to Covid-19 vaccines around the world as they become available, is aiming to provide some two billion doses by the end of next year.

It has already secured hundreds of millions of doses of vaccine candidates being developed by AstraZeneca, Novavax and Sanofi-GSK.

WHO senior advisor Bruce Aylward said the organisation was looking at a range of other jabs, as well as the current frontrunners.

He said WHO was "in conversations" with Pfizer and Moderna about whether their products could be part of "early roll-out of vaccines".

But, he stressed, "we also need to make sure that they are at prices that are appropriate for the populations we are trying to serve and the countries we are trying to help."

US pharmaceutical giant Pfizer has, along with German BioNTech, created the first coronavirus jab to receive regulatory approval in a number of Western countries. Vaccination campaigns have already begun in Britain and the United States.

The Moderna vaccine is expected to quickly receive approvals as well.

Light, but a long tunnel

Both vaccines use cutting-edge technology and have been shown in Phase III trials to be highly effective -- and they are expected to be expensive.

But Aylward hailed public comments from Pfizer chief Albert Bourla in which he talked about cutting prices for low-income countries.

"He has said we are committed to making sure that our products see global use and we recognise that requires pricing it at the right level to be able to make that work," Aylward said.

"So there is a strong commitment from Pfizer out there to be able to do that."

Covax wanted to have a diverse portfolio of vaccines to offer and would evaluate "any product out there with demonstrated efficacy, safety, quality", he added.

The vaccines developed by China and Russia could also be evaluated for inclusion "if they meet the standards for efficacy and safety", he said.

A year into the pandemic, which has claimed more than 1.6 million lives worldwide, Aylward hailed the positive vaccine news over the past month.

"There is light at the end of the tunnel," he said. But while there was "a bright light at the end of it, getting brighter, it is a long tunnel."