WHO Director-General Tedros Adhanom Ghebreyesus has called for countries around the world to join forces to tackle the virus together.
Mr Tedros said 78 high-income countries had now joined the Covax global vaccine allocation plan, bringing the total to 170 countries, adding that joining the plan guaranteed those countries access to the world's largest portfolio of vaccines.
Notable by its absence is the US which has secured its own supplies bilaterally.
"Vaccine nationalism will prolong the pandemic," Tedros told reporters at a WHO briefing in Geneva, without mentioning any specific countries.
Mr Tedros thanked Germany, Japan, Norway and the European Commission for joining Covaz during the last week.
Widespread vaccinations not available till mid-2021
A WHO spokeswoman said earlier on Friday that the organisation does not expect widespread vaccinations against COVID-19 to be available until mid-2021, citing the need for rigorous checks on their effectiveness and safety.
The WHO's chief scientist, Soumya Swaminathan, told the briefing that no vaccine is "going to be mass-deployed until regulators are confident, governments are confident, and the WHO is confident it has met the minimum standard of safety."
All vaccines "need to go through the full Phase III trials" she added.
The four stages of a vaccine trial are enumerated in the chart below.