French President Emmanuel Macron said on Friday that AstraZeneca's coronavirus vaccine appeared not to be effective for people over 65 years of age.
Speaking to reporters only hours before the European Medicines Agency (EMA) recommended the vaccine for adults of all ages, Macron also questioned Britain's decision to delay the second dose of Covid vaccines to inoculate more people.
Macron said there was "very little information" available for the vaccine developed by the British-Swedish company and Oxford University.
"Today we think that it is quasi-ineffective for people over 65," he told the reporters, his office confirmed to AFP.
"What I can tell you officially today is that the early results we have are not encouraging for 60 to 65-year-old people concerning AstraZeneca," he said.
Macron said he was awaiting the EMA's verdict -- which came later Friday -- and also that of France's own health authority "because they have the numbers".
The French expert decision on the vaccine is expected at the start of next week, according to sources close to the health authority.
"I don't have any data, and I don't have a scientific team of my own to look at the numbers," Macron acknowledged.
Addressing the UK's vaccination strategy of stretching the time between first and second doses in order to give the protection afforded by the first dose to the maximum number of people, Macron said "the objective is not to have the largest possible number of first doses".
In an attempt to speed up its vaccine rollout, UK health chiefs have delayed second doses for up to 12 weeks.
"When you have all the health agencies and the manufacturers who are telling you that for it to work you have to have two injections with a maximum of 28 days between the two, as is the case with Pfizer/BioNTech, and you have countries that have a vaccination strategy of only giving one injection, I am not sure that it's totally serious," said Macron.
"Scientists tell you that we accelerate mutations when you only give one injection because people are less well covered and therefore the virus adapts.
"We lie to people when we say 'you are vaccinated'. You have a first dose of a vaccine that is made up of two," he added.
Meanwhile, Germany's vaccine commission on Friday maintained its advice against using AstraZeneca's coronavirus vaccines on older people.
"The reason is because there is currently insufficient data on the effectiveness of the vaccines on people above 65 years old," said the commission known as STIKO.
The advice by the panel of medical experts will be taken into account by the government as it officially draws up its decree on usage of the vaccine.
The discussion about the right target age group for the vaccine has compounded controversy surrounding AstraZeneca's vaccine.
The European Commission Friday published a redacted version of its contract with the drugs giant, hoping to prove the company had breached a commitment on vaccine deliveries.
Brussels is furious with the pharmaceuticals company after it warned that it would only be able to deliver a fraction of the doses the EU had been expecting once the vaccine is approved for use in the bloc.