The pharmaceutical giant Pfizer on Wednesday said that its COVID-19 vaccine candidate was found to be 95 per cent effective in the final analysis of the Phase 3 trial, adding it had the required two-months of safety data and would apply for emergency US authorization within days.

The drugmaker said the efficacy of the vaccine developed with German partner BioNTech SE was consistent across age and ethnicity demographics, and that there were no major side effects, a sign that the immunization could be employed broadly around the world.

The study reached 170 confirmed cases of COVID-19, with the vaccine candidate BNT162b2 demonstrating 95 per cent efficacy beginning 28 days after the first dose, Pfizer said.

Pfizer Inc and BioNTech could secure emergency US and European authorization for their COVID-19 vaccine next month after final trial results showed it had a 95% success rate and no serious side effects, the drugmakers said on Wednesday.

The vaccine's efficacy was found to be consistent across different ages and ethnicities - a promising sign given the disease has disproportionately hurt the elderly and certain groups including Black people.

The US Food and Drug Administration could grant emergency-use by the middle of December, BioNTech Chief Executive Ugur Sahin told Reuters TV. Conditional approval in the European Union could be secured in the second half of December, he added.

"If all goes well I could imagine that we gain approval in the second half of December and start deliveries before Christmas, but really only if all goes positively," he said.