While Israel has given at least one shot of a two-dose vaccine to over 40% of its population and that figure in Britain is 10%, the EU total stands at just over 2%.
Onerous regulations and paperwork in some countries and poor planning in others have contributed to the delay, as did a more deliberate authorization process for the shots.
Some drugmakers say they won't be able to meet their initial vaccine doses because of problems in expanding production capacity.
Health authorities in Spain say they are running short of COVID-19 vaccines due to delays in deliveries by pharmaceutical companies.
Northeast Catalonia, home to Barcelona, says 10,000 people who had received the first dose of the Pfizer vaccine won't be able to get their required second dose administered as planned 21 days later.
Regional authorities for the territory surrounding the capital of Madrid also say they were halting the administration of the first shot of the Pfizer vaccine to ensure that those awaiting a second shot could get it as scheduled.
Spain has administered 95% of the 1.3 million vaccines it has received as part of the EU plan, according to its health ministry.
Only 123,000 people have received the full vaccine. Spain along with the rest of the European Union has suffered delays since Pfizer announced two weeks ago a temporary reduction in deliveries so it could upscale its plant in Puurs, Belgium.