While almost 55% of adults in the EU have been fully vaccinated against Covid-19, the coverage remains 'highly variable' from one country to another, according to a Commission spokesperson.
The "vaccine tracker" of the European Centre for Disease Prevention and Control (ECDC) shows what proportion of the adult population has already been partially or fully vaccinated, country by country.
However, the overall figures lag behind those of the Commission, due to delays in reporting.
Belgium, with 62.7% of adults fully vaccinated according to ECDC data, is above the figures for the EU as a whole, but Slovakia has a 41.9% share of fully vaccinated adults, for example.
"Low vaccination rates are a cause for concern," said Commission health spokesman Stefan De Keersmaecker on Thursday.
This is the main topic that is discussed by Commissioner Stella Kyriakides during her visits to various capitals, where she discusses the progress of vaccination with local authorities.
While the EU has set itself the target of reaching full vaccination of at least 70% of adults this summer, each individual Member State should also exceed this threshold to avoid "pockets" where the virus can mutate, De Keersmaecker told reporters.
"Enough doses have been provided, it is important to administer them without delay," he said.
However, vaccination itself is the responsibility of the Member States, which the Commission is trying to help, for example in terms of communication with the population, or in terms of logistics with procedures for the joint purchase of adequate needles, according to De Keersmaecker.
As for vaccination beyond the EU's borders, 'Team Europe' (the EU institutions and each of the 27 Member States together) is expected to go well beyond the pledge it made last May to share 100 million doses of vaccine with low- and middle-income countries by the end of the year.
There have already been commitments for at least 200 million doses, the Commission said Thursday. Most of these doses are going through the Covax mechanism.
The Brussels Times