WHO Director-General Tedros Adhanom Ghebreyesus has called for "fair allocation" of a Covid-19 vaccine after drugmakers Pfizer and BioNTech this week said that their vaccine candidate was found to be more than 90 per cent effective in preventing the disease in interim analysis of data.

Addressing the member states at the 73rd World Health Assembly on Tuesday, the WHO chief said that the UN health agency welcomes Pfizer's "promising news" and expect additional effective vaccines in near future along with advances in testing and therapeutics.