- Reality Check
image copyrightEPAimage captionA US vaccine donation via Covax arrives in East Timor
The US has pledged to donate 500 million doses of the Pfizer-BioNTech vaccine, as many poorer countries struggle to get their populations vaccinated against coronavirus.
US President Joe Biden, in the UK for a G7 summit, said on Thursday that this would be "the largest single purchase and donation of Covid-19 vaccines by any single country ever".
He vowed the US would be "the arsenal of vaccines in our fight against Covid".
Speaking alongside him, Pfizer CEO Albert Bourla said he could see a "light at the end of the tunnel".
The 500 million sounds like a lot – but what difference will it make?
What has the US promised?
It has agreed to purchase the doses from Pfizer at a "not for profit" price.
Mr Biden said the vaccines "would start to be shipped in August" to "nearly 100 low- and lower-middle income countries".
It is understood that 200 million doses will be distributed by the end of this year, and then a further 300 million by June 2022.
They will be provided to countries through the international Covax vaccine-sharing scheme, and a programme run by the African Union, that aims to vaccinate the most vulnerable 20% of every nation around the world.
The US had already pledged to give 80 million doses to countries around the world.
- How does Covax work?
- How many vaccines are rich countries sharing?
The latest US donation is significantly larger than that pledged by other nations so far.
The World Health Organization (WHO) director for Africa, Dr Matshidiso Moeti, says the US donation "is a monumental step forward".
Some other G7 countries have started to donate further doses. Aside from the US, the nations in the G7 are Canada, France, Germany, Italy, Japan and the UK.
image copyrightGetty Imagesimage captionPresident Biden is in the UK for a meeting of G7 leaders
At a summit in early June, hosted by the Global Alliance for Vaccination and Immunisation (Gavi), it was announced that so far, more than 132 million doses had been shared by various countries.
This included more than 54 million doses available for short-term supply donated by Belgium, Denmark and Japan, as well as additional supplies from Spain and Sweden.
More pledges of doses are expected at the G7 summit.
Are the vaccine donations enough?
The scale of the challenge is huge, and vaccines are needed immediately.
WHO Director-General Tedros Adhanom Ghebreyesus has said: "To vaccinate at least 10% of the population in every country by September, we need an additional 250 million… vaccine doses."
He said 100 million of those doses were needed in June and July.
"Sharing vaccines now is essential for ending the acute phase of the pandemic," he said.
In February 2021, 1.3 billion doses had been secured for delivery this year to poorer countries, and were expected to be rolled out in the coming months.
The original Covax objective was to deliver two billion doses of vaccine worldwide by the end of this year, but the aim now is to get 1.8 billion doses to 92 lower income economies by early 2022.
One vaccine expert, Prof Peter Hotez of the Baylor College of Medicine in the US, outlined the challenge in a tweet , saying "we desperately need a US foreign policy and American leadership to take on this challenge".
My take: 1.1 billion people in SS Africa, 650 million in Latin America, 0.5 billion in smaller LMICs in SE Asia. That’s 2-3 billion people, 5-6 billion vaccine doses. We desperately need a US foreign policy and American leadership to take on this challenge https://t.co/58wOFdagpf
— Prof Peter Hotez MD PhD (@PeterHotez) June 9, 2021
The BBC is not responsible for the content of external sites.View original tweet on Twitter
And all these commitments are way off the 11 billion doses the WHO estimates are needed to vaccinate the whole world to a level of 70%, the point at which transmission of the virus could be significantly affected.
"The world needs urgent new manufacturing to produce billions more doses within a year, not just commitments to buy the planned inadequate supply," tweeted Peter Maybarduk, director of Public Citizen's global access to medicines programme.
Niko Lusiani, of Oxfam America, said the US doses were welcome but were still "a drop in the bucket compared to the need".
What's held up getting vaccines out?
One of the main challenges has been the delivery of vaccines.
As of 8 June, the Covax scheme had shipped just 81 million doses to 129 member countries.
That contrasts with more than 300 million doses delivered to the US population alone, which means other parts of the world that are relying on Covax are far behind.
The Covax scheme has mostly relied on the Oxford-AstraZeneca vaccine produced in India.
image copyrightEPAimage captionAstraZeneca vaccines have been the mainstay of the Covax sharing scheme
However supplies were severely hit in March, April and May after India halted all major exports of the vaccine when it was hit by a massive second wave.
A total of 1.1bn doses of Covishield (AstraZeneca) were ordered from India's largest manufacturer – the Serum Institute of India (SII).
So far, it has supplied just 30 million doses to Covax, with nearly 190 million doses held up as it struggled to ramp up its production.
It says exports will only resume by the end of the year and that the company is focusing on meeting India's own needs.
There has also been an issue in some countries about the slow uptake and distribution of vaccines already delivered, with some African nations unable to use doses before they expire.
"While more vaccines are vital, some African countries must ramp up actions to swiftly roll out the vaccines they have," the WHO said.
The Pfizer-BioNTech vaccine donation from the US may go some way to addressing longer-term demand, but in the short-term, supply and logistical issues are likely to continue to be an obstacle.
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