Germany’s vaccine committee has said AstraZeneca’s Covid jab should only be given to people aged under 65.
The committee cited “insufficient data” over its efficacy for older people.
The European Medicines Agency is to decide on Friday whether to approve the vaccine for use across the EU.
The UK has been using the AstraZeneca vaccine in its mass immunisation programme for weeks now, and public health officials say it is safe and provides “high levels of protection”.
The German announcement comes as the EU is in dispute with leading manufacturers over a shortage of vaccines on the continent.
UK-based AstraZeneca has said production issues at its Europe-based plants mean it will be unable to deliver the promised number of doses to the bloc.
But the EU says the firm must honour its commitments and deliver the jabs by diverting stock from the UK. It is calling for “robust action” to secure the supply.
Pfizer-BioNTech has also cut the number of doses it is delivering to the 27-member bloc.
The independent vaccine commission advising the German government said on Thursday that there were “currently insufficient data available to assess the vaccine efficacy from 65 years of age” and recommended “the AstraZeneca vaccine… should only be offered to people aged 18-64 years at each stage”.
But Dr Mary Ramsay, Head of Immunisations at Public Health England, said both the AstraZeneca and Pfizer-BioNTech vaccines are “safe and provide high levels of protection against Covid-19, particularly against severe disease.
“There were too few cases in older people in the AstraZeneca trials to observe precise levels of protection in this group, but data on immune responses were very reassuring.”
UK Prime Minister Boris Johnson said he was not worried by the German recommendation.
“Our own authorities have made it very clear that they think the Oxford-AstraZeneca vaccine is very good and efficacious, gives a high degree of protection after just one dose (…) and the evidence that they’ve supplied is that they think it is effective across all age groups,” he said.
Meanwhile, Paul Hunter, professor of Medicine at the University of East Anglia, told BBC News that the elderly should not worry about receiving the jab: “We do know that it is safe in people over 65.
They have much fewer side effects than younger people and it almost certainly provides substantial benefits in terms of preventing severe disease and reduce the chances of going into hospital.”