FactCheck has previously reported on how AstraZeneca and Pfizer, the drug companies supplying Covid-19 vaccine to the UK, have both delivered fewer doses of vaccine than were originally forecast.

So far, this hasn’t stopped the UK vaccine rollout proceeding at pace, with more than 31 million adults getting either a first or second jab so far.

But we are now entering a period of tightened supply. Last week, an internal NHS letter warned of a “significant reduction in weekly supply” from next week.

Volumes would be “significantly constrained” for weeks and vaccination centres should concentrate on the over-50s and increasing numbers of second doses, rather than start injecting people under 50.

After some delay, the government admitted there was a supply issue, and blamed delays in sourcing 10 million doses of AstraZeneca vaccine from India.

Ministers insist Britain is still on track to meet its main targets of offering a first jab to all over-50s by April 15, and all adults by the end of July. Everyone who has had a first dose has been promised a second one within 12 weeks.

The latest figures

It’s not easy to find out how much AstraZeneca and how much Pfizer vaccine we have. The information is not available on the government’s coronavirus dashboard and the Department of Health did not provide a breakdown to FactCheck when asked.

But the information is available in this little-known corner of the government’s gov.uk website, which details side effects reported to the Medicines and Healthcare products Regulatory Agency through the “yellow card” system.

We have eight weekly data releases now, going back to January 24 this year.

That was ten days after Tom Keith-Roach, the president of AstraZeneca UK, told the House of Commons science and technology committee: “We are scaling up, as we have said, very rapidly—this will happen imminently—to releasing 2 million doses a week.”

He added that there would be “some small inter-week variation around that average of 2 million doses”. Ministers have always said there would be fluctuations in the total supply of vaccines from week to week.

Here are the figures released so far on the government website, showing the cumulative doses of Pfizer and AstraZeneca vaccines administered week by week:

The UK has only administered 2 million first doses of the AstraZeneca vaccine in three out of eight weeks. The average weekly number of first doses since January 24 is just over 1.7 million a week.

The data release says the second jabs being administered are “mostly Pfizer”. This suggests a small number of these could be AstraZeneca, but we don’t know how many.

These are stats for the numbers of jabs administered, not the numbers of doses delivered by AstraZeneca in the first place.

FactCheck has repeatedly asked AstraZeneca whether it is hitting the 2 million a week target or not, but we have not received replies.

The UK government says it cannot provide data on the number of doses being supplied by the company, citing commercial confidentiality and security issues.

Pfizer numbers stall

It’s also noticeable that we appear to have administered no first doses of Pfizer vaccine in the latest week for which figures are available: March 7 to March 14:

The obvious question here is whether the UK has used up so much of its limited supply of Pfizer vaccine that it will now only administer second doses of the vaccine and is now dependent on AstraZeneca’s product for all the first jabs.

This comes at a time when AstraZeneca is under fire from the European Union for failing to hit supply targets, when the Indian government has told AstraZeneca’s partners in that country to stop exporting vaccines, and when there are outstanding questions on whether the company is delivering the promised 2 million doses a week to the UK.

Should we be worried? FactCheck put all this to the Department of Health. A spokesman told us: “Our vaccination programme continues to make phenomenal progress – with over 31 million vaccines administered so far.

“From the outset we have been clear that supply will vary over time, but we remain on course to offer a first vaccine to over 50s by mid-April and all adults by the end of July.

“We are confident in our vaccine supplies and are in constant contact with the manufacturers – who are doing a phenomenal job – to understand and address any potential pinch points.”