Vaccine makers working non-stop to plug supply gap: WHO

"Solidarity does not necessarily mean that each country in the world starts (vaccinating) at exactly the same moment ... The good understanding is that no one is safe before everyone is safe," Kluge told an online news briefing.

Asked about delays in expediting Pfizer and AstraZeneca vaccines to patients across the 27-nation European Union, Kluge said governments and manufacturers should work together to addressing "teething problems" in the rollout.

As he spoke, Europe's fight to secure COVID-19 vaccine supplies sharpened when Britain demanded that it receive all the shots it paid for after the EU asked AstraZeneca to divert supplies from the UK.