The European Union’s infectious diseases agency has urged countries to push ahead with their primary coronavirus vaccination programmes over the need for booster shots.
Approved vaccines are "currently highly effective" in limiting the impact of COVID-19, the European Centre for Disease Prevention and Control (ECDC) said on Thursday.
"The priority now should be to vaccinate all those eligible individuals who have not yet completed their recommended vaccination course," it added.
On Wednesday, France became the first large EU country to start administering booster shots of the COVID-19 vaccine to people over 65 and those with underlying health conditions as the delta variant spreads in the country.
Spanish health authorities are also due to debate taking similar measures next week.
But the ECDC said there was no "urgent need" for booster doses in the general population.
Additional shots could however be considered for people "with severely weakened immune systems" if the first shots do not protect them enough, it added.
Meanwhile, the European Medicines Agency stressed that it has not yet concluded its assessment of the data on booster doses of COVID-19 vaccines.
After a slow start to Europe’s vaccine drive, the European Commission announced this week that on average 70% of adults are fully vaccinated across the 27-nation bloc.
But national vaccination rates vary, with Bulgaria and Romania notably slow with their programmes.
The World Health Organization had also urged governments to donate available vaccines to those countries in need.
EU commission spokesman Stefan De Keersmaecker said on Thursday that the bloc has enough shots should scientific evidence suggest that boosters might be broadly required.
Brussels recently concluded a contract with BioNTech-Pfizer for 1.8 billion additional doses from 2021 to 2023 and a second contract with Moderna for 150 million shots for the EU.
"We have taken the necessary measures to be ready," De Keersmaecker said.