A patchwork of campaigns for an extra COVID-19 shot are being rolled out across the European Union even before the region's drug watchdog rules on whether they are safe and effective.

Italy, France, Germany and Ireland have already started to administer booster shots and the Netherlands plans to do so soon but only to people who are immuno-suppressed.

But several EU countries are waiting for the European Medicines Agency (EMA) to give its opinion this week.