GENEVA — A COVID-19 vaccine may be rolled out by March 2021 to the most vulnerable, which along with other advances could fundamentally change the course of the pandemic, Reuters cited a senior World Health Organization (WHO) official as saying on Monday.

Bruce Aylward told the WHO's annual ministerial assembly that interim results from Pfizer Inc's late-stage vaccine trial were "very positive".

"By March as a result of the extraordinary work happening globally we could be in a position to fundamentally change the direction and the dynamic of this crisis," Aylward told the 194-member state forum.

"There is still much work to be done, this is just interim results...but some very positive results coming today which should hold great promise hopefully for the entire world as we move forward," Aylward told the 194-member state forum.

"By March as a result of the extraordinary work happening globally we could be in a position to fundamentally change the direction and the dynamic of this crisis," he added.

Pfizer said its experimental COVID-19 vaccine was more than 90% effective, raising hope as the pandemic accelerates with over 50 million cases and 1.2 million deaths.

WHO Director-General Tedros Adhanom Ghebreyesus also welcomed the "encouraging vaccine news" in a tweet.

The Pfizer-BioNTech candidate was not among the original nine vaccines forming part of a WHO-run "COVAX" facility to finance and distribute them fairly around the world.

However, the companies have expressed interest in supplying the program. The WHO has said more vaccines are under consideration.

Pfizer and BioNTech said they expected to seek US authorization this month for emergency use of the vaccine, raising the possibility of a regulatory decision as soon as December.

Aylward gave an upbeat assessment of overall prospects. "In diagnostics we are in a position to massively expand testing globally, in therapeutics we have sufficient tools right now to substantially reduce the risk of dying from this disease and in the area of vaccines — with the news of today especially — we are on the verge of having the readiness in place to roll out doses for high-risk populations in the late first quarter, early 2nd quarter."

The interim analysis of the vaccine developed by Pfizer and BioNTech looked at the first 94 confirmed cases of coronavirus among the more than 43,000 volunteers who got either two doses of the vaccine or a placebo.

It found that fewer than 10 percent of infections were in participants who had been given the vaccine. More than 90 percent of the cases were in people who had been given a placebo.

In an announcement on Twitter, Pfizer said: We are proud to announce, along with BioNTech Group, that our mRNA-based vaccine candidate has, at an interim analysis, demonstrated initial evidence of efficacy against COVID19 in participants without prior evidence of SARS-CoV-2 infection.” — Agencies