From a reputable EU broadcaster - note especially the last two paragraphs :
"The European Commission hopes to produce a mechanism by the end of this week which would register all Covid-19 vaccines manufactured in Europe and exported to non-EU countries.
This follows the escalating row between the EU and AstraZeneca over a shortfall of up to 60% in the amount due to be delivered to European capitals in the first quarter, once the vaccine is authorised, as expected, on Friday.
Although the commission has not spelled it out, the suspicion among officials is that none of AstraZeneca's other customers, notably the UK, suffered any big drop in supply.
The commission said the transparency mechanism is not about blocking exports of vaccines, but about knowing who is getting what"
https://www.rte.ie/news/coronavirus/2021/0126/1192035-covid-19-vaccine/