LONDON — The European Medicines Agency has approved new manufacturing sites for coronavirus vaccines made by Pfizer, Moderna and AstraZeneca in a move that could significantly boost Europe’s supply of the shots.

In a statement published on Friday, the EU medicines regulator says it had approved sites in the Netherlands, Germany and Switzerland for vaccines made by the companies.

The new approvals come amid the 27-nation bloc’s struggles to ramp up COVID-19 vaccination and repeated delivery delays and manufacturing problems. In addition, the EMA says it was granting “more flexible storage conditions” to the Pfizer vaccine — which was cleared on the basis that it needed ultra-cold freezer temperatures for storage and delivery.