The head of the European Medicines Agency told AFP on Friday that all countries must have access to coronavirus vaccines, as G7 leaders were set to pledge one billion doses for poor nations.
Emer Cooke added in an interview that while the Amsterdam-based watchdog was confident current vaccines were effective against all different variants, that could "change quickly".
The comments by Ireland's Cooke -- who took over at the EMA late last year as it plunged into the scramble for a Covid vaccine -- came as G7 leaders met in Britain to discuss how to recover from the pandemic.?
"This is not within the competence of the EMA so I can only speak from a personal perspective, where I really believe we need to ensure access, availability and access throughout the world, not just in the countries that have the means to pay for them," Cooke said.
Campaigners say the G7's pledge for this year and next -- including 500 million US doses -- is far too little, too late to end a pandemic that has claimed over 3.7 million lives worldwide and is still?spawning new variants.
Despite a slow start, the EU has become one of the world's better protected regions, thanks to a stable of four vaccines approved by the EMA since December -- Pfizer/BioNTech, Moderna, AstraZeneca and Johnson & Johnson.
"To be honest, I thought we would be much further behind. The fact that we have four vaccines authorised within 15 months of the declaration of a pandemic is exceptional," said Cooke, speaking via Zoom.
- 'Variants are controlled' -
But the emergence of new variants has presented a new challenge, particularly the Delta variant which first emerged in India.
"So far we're confident that the circulating variants are controlled by the vaccines. But it can change very quickly," Cooke said.
The EMA has been working with vaccine makers to make sure they could adapt their jabs if needed, she said.
Another hurdle has been issues over the AstraZeneca and Johnson & Johnson vaccines, particularly over rare and occasionally fatal blood clots.
In another setback on Friday, the EMA said it was recommending that a batch of J&J doses in the EU should be held back as a precaution after a batch in the US was contaminated with material from another vaccines.
"It is of course not a situation that we're very happy with," she said, adding however that they hoped to have the situation resolved by July or August.
Cooke however played down suggestions these problems could affect public confidence in the vaccines.
"We have a system that works because we are able to detect what may be or may not be possible side effects," she said.
- 'Hugely challenging' -
While the EU is looking to add to its vaccine portfolio, it has yet to approve jabs made by Russia and China that are widely used in other parts of the world.
Russia's Sputnik V vaccine is currently under review by the EMA but, "I believe we're waiting for additional information from the company to proceed to the next stage," Cooke said.
Responding to comments by Russian officials that the process should not be "politicised", she replied: "We judge every vaccine on its scientific merits in an independent process that is not influenced by politics."
She declined to give any estimate for the approval of Sputnik or the other three vaccines currently under review -- CureVac, NovaVax, and China's Sinovac.
Beijing has meanwhile been under pressure over the origins of the pandemic, with the World Health Organization also pressed by the US and EU to probe whether it emerged from an animal source in China or a laboratory leak.
Cooke, who previously worked at the WHO, said this was "not something EMA would ever get involved with" but that "if there is a greater understanding of how this evolved then maybe we can do more to prevent future occurrences".
Reflecting on a frantic first seven months in charge, Cooke said: "It's been hugely challenging but very very motivating.
"This is a time where you feel like you can make a difference, and that's very rewarding. And you can almost forget all those late nights and early mornings."