EU drug regulators are due to grant only restricted approval of AstraZeneca's COVID-19 vaccine, according to Germany's health minister.
The expected authorisation, which may limit its use on people aged between 18 and 64 is centred on the lack of data about its effectiveness for the over-65s.
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Jens Spahn said authorities are waiting to see what advice the European Medicines Agency (EMA) issued on the vaccine before Germany adjusted its own guidance for doctors.
"We don't expect an unrestricted approval," Mr Spahn said.
It isn't clear whether EU authorities would explicitly recommend against using the vaccine on people over 65, or only note that there is a lack of data.
It follows questions being raised over how effective the AstraZeneca vaccine, developed with Oxford University, is in protecting older people.
Only 12% of those who took part in the trials were over 55 and they were enrolled later, so there has not been enough time to collate the results.
On Thursday, a draft recommendation from Germany's vaccination advisory committee said the AstraZeneca vaccine should currently only be given to people aged 18-64.
UK regulators acknowledged the limited data for older people when it cleared the jab last month for people over 18, but Public Health England has said details on the immune response for those 65 and over had been "reassuring".
A separate study testing the AstraZeneca vaccine in the US is still under way.
The shot would be the third COVID-19 vaccine given the go-ahead by the EMA after jabs by Pfizer and Moderna, which were authorised for all adults.
Mr Spahn's comments come amid a bitter wrangle between AstraZeneca and the EU over delayed supplies.
Brussels has hit out at AstraZeneca after the drug giant said it would reduce initial deliveries from 80 million doses to 31 million, blaming production problems.
EU chief Ursula von der Leyen has said the contract contained binding orders and the bloc has raised the threat of legal action to secure COVID-19 stocks.
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Brussels has now published the deal in its escalating dispute, which has seen the EU demand doses be sent from UK plants to make up for the shortfall.
Cabinet Office minister Michael Gove said the government will not allow vaccines intended for Britain to go to the EU.
This has led German MEP Dr Peter Liese to warn the UK it would be acting like former US president Donald Trump if it pursued a "UK first" contract for the vaccines.
Meanwhile, a fourth COVID-19 vaccine could be approved for use in the UK within weeks after late-stage trials suggested it was 89% effective in preventing coronavirus.
