The EU's disease agency launched a Covid-19 vaccine tracking tool on Monday, providing an overview of countries' efforts in the rollout of inoculations across Europe.

The first set of data was available on the website of the European Centre for Disease Prevention and Control (ECDC), covering the 27-nation bloc plus the UK, Iceland, Liechtenstein and Norway. 

However it was still incomplete on Monday, as some countries had yet to report their national data. Member states are expected to report their numbers twice a week.

As a result, the tracker indicated the number of vaccine doses administered in its member states as of Monday was 8.23 million, though in reality the number is much higher.

"In this early phase of vaccination campaigns, monitoring the number of doses distributed to countries and doses received by individuals provides useful insights into the progress of vaccine deployment and the evolution of vaccination campaigns," the ECDC said in a statement.

"It also provides initial indicative estimates of vaccine uptake for the first and second dose per population targeted by vaccine recommendations on the national level."