The European Commission believes Europe is on track to achieve "community immunity" to COVID-19 by late summer thanks to speeded-up vaccination dose deliveries, a spokesman said on Tuesday.

The EU should meet its mid-September target of fully inoculating most of its adult population, given that deliveries over the next three months should be more than triple those of the first quarter, Stefan de Keersmaecker told journalists.

"We believe that, on the basis of this, we will have enough doses of the vaccine to reach our very important target of about 70 per cent of the adult population," he said.

"That would leave us in a situation where we have sufficient community immunity to fight the virus."

He confirmed commission figures showing that first quarter vaccine deliveries to the 27-nation bloc amounted to 107 million doses — far below what was expected.

But there should be "about 300 to 360 million doses" supplied between now and the end of June. The EU has a total population of 450 million, of which 365 million are adults.

To reach the 70 per cent adult population target, 255 million people would need to be fully vaccinated — meaning two jabs in most cases, or just one jab with the Janssen vaccine produced by Johnson & Johnson.

According to a confidential document used by EU diplomats to monitor vaccine deliveries, seen by AFP, 23 of the 27 member states should have vaccinated more than half of their populations based on total deliveries in the first half of this year.