Spain and Italy have moved to limit the use of the Oxford/AstraZeneca vaccine to people aged above 60, in shifts that will complicate the countries’ efforts to step up their vaccination programmes. The decisions by Madrid and Rome on Wednesday night came after the European Medicines Agency said earlier in the day that there was a link between very rare blood clots in the brain and the AstraZeneca jab.

While the EMA, the EU’s pharmaceuticals regulator, did not change its guidance for who should take the vaccine, it noted that “so far, most of the cases reported [of blood clots] have occurred in women under 60 years of age within two weeks of vaccination”.

Belgium separately restricted the AstraZeneca vaccine to those aged 56 or older for a minimum of four weeks on Wednesday. Australia moved on Thursday to limit further use of the shot in those younger than 50, with Canberra saying the BioNTech/Pfizer inoculation should be used instead.

France and Germany had also previously restricted the use of the shot for the over-55s and over-60s, respectively — trusting that other vaccines, such as that from BioNTech/Pfizer and a new one-shot inoculation from Johnson & Johnson, will be sufficient to make up the lag in the EU’s vaccination programme.

The UK, which is well ahead of the EU in the vaccine rollout, abruptly changed its guidance over the AstraZeneca vaccine on Wednesday, recommending that people aged between 18 and 29 are offered alternative jabs. Sweden and Finland allow its use only in the over-65s, while Denmark and Norway have suspended its use until at least next week.