Four Spanish regions have stopped administering doses from a batch of AstraZeneca's COVID-19 vaccine following reports of the formation of blood clots in some people who had been vaccinated, although the central government plans to keep using the shot.
Austria earlier stopped using the batch of AstraZeneca shots while it investigated a death from clotting and a case of pulmonary embolism.
Several Nordic countries suspended use of the AstraZeneca vaccine on Thursday and Spain's central Castille and Leon region decided on Friday to also stop using it as a precaution.
Officials in Andalusia, Asturias and the Canary Islands said they would not use shots from the suspect batch but would continue giving jabs from other deliveries.
None of the regions has detected any severe adverse effects.
A police union said most of the doses from the batch in question went to police officers and asked the Health Ministry to monitor them closely.
Health Minister Carolina Darias said authorities had only detected light side effects such as headaches, dizziness and intestinal troubles, while the frequency of blood clots among vaccinated people was no higher than among the general population.
In a statement on Thursday, AstraZeneca said it had found no evidence of an increased risk of pulmonary embolism or deep vein thrombosis in safety data of more than 10 million records.
The World Health Organization is looking into the issue but said there was no reason not to use the drug, while Europe's EMA medicines regulator backed it and said the benefits outweigh the risks.
Darias said Spain would continue to administer the AstraZeneca vaccine until it received further guidance from the EMA.
Her ministry has administered some 5.2 million doses of coronavirus vaccine, around 15% of which were made by AstraZeneca.
Since taming a third wave that peaked in late January, Spain's infection rate has fallen to its lowest since August but the rate of decline is slowing.
The government reported 5,348 new cases on Friday, bringing the total to nearly 3.2 million. Deaths increased by 173 to 72,258.