The UK is set to face short-term delays in delivery of the Pfizer coronavirus vaccine as the pharmaceutical company upgrades its production capacity.

Pfizer is upscaling production at its plant in Puurs, Belgium, in efforts to produce more doses than originally planned for 2021 – temporarily reducing deliveries to all European countries.

Shipments of the vaccine, produced in partnership with Germany’s BioNTech, to the UK are set to be affected towards the end of January, with delays running into early February. 

But the US-based firm has insisted that the overall number of doses due to be delivered between January and March will remain the same.

A government spokesperson has also said plans are still in place to vaccinate all four of the UK’s top-priority groups by the middle of February.

The vaccine from Pfizer is not the only candidate available in the UK, with the University of Oxford and AstraZeneca jab also currently being rolled out.

Six health and social affairs ministers from Sweden, Denmark, Finland, Lithuania, Latvia and Estonia signed a joint letter on Friday, which states: “This situation is unacceptable.”

It continued: “Not only does it impact the planned vaccination schedules, it also decreases the credibility of the vaccination process.” 

Germany, Europe’s largest purchaser of the Pfizer vaccine, called the decision surprising and regrettable, while Canada said it is also set to be affected.

Italy’s Covid-19 special commissioner, Domenico Arcuri, said Pfizer would from Monday cut deliveries of vaccine shots to the country by 29%. The company had not been able to say for how long it would be curtailing its supplies, said Arcuri.

A Pfizer spokeswoman said: “We understand a change to deliveries has the potential to create uncertainty.

“However, we can confirm the overall projected volumes of delivery to the UK remain the same for quarter one (January to March).

“We continue to liaise with the UK government and the vaccines taskforce to work through short-term impact of these changes to our January deliveries and support the goals of the UK Covid-19 vaccination programme.”

The UK has secured 40 million doses of the vaccine from Pfizer and BioNTech.

A government spokeswoman said: “We are in the process of understanding the implications of Pfizer’s announcement today to our plans.

“However we continue to plan to hit our target of vaccinating all four priority groups by February 15.”