The said 62,000 doses of AstraZeneca vaccine were supposed to arrive in Poland on Thursday morning. They were meant to be distributed to vaccinate the so-called group zero. "Today's supply of AstraZeneca vaccines has been called off. It's possible that it will reach Poland next week" - Mr Kuczmierowski said.

He added that the company had explained the delay with "formal issues". "As a result, the supplies have been rescheduled for next week".

"AstraZeneca has informed us last last minute. In our view, such situation is absolutely scandalous. Such practices hamper the national vaccination schedule" - said the head of RARS.

He pointed out that according to the schedule, on Monday, March 8, the country expects a supply of Pfizer vaccine. "We haven't confirmed the exact date of Moderna vaccine delivery yet" - said Michał Kuczmierowski.

He also reassured that although the delay should not derail the vaccination programme, Poland is likely to receive a total 6-8 million doses in the first quarter of 2021, instead of the promised 14 million.

"The system we've created allows us to easily vaccinate 4-4,5 million Poles per month. Meanwhile, we need to adjust to the deliveries, which are very unsatisfactory" - Mr Kuczmierowski stressed.

The European Commission reassured that a special committee has been created to ensure constant communication between the vaccine producers, member states, and the EU.

The spokesman for the EU executive, Stefan De Keersmaecker, said: "We're in constant contact with the company (AstraZeneca) and we're doing all we can to ensure these crucial deliveries".