Why coronavirus numbers tell complex stories

However, approximately 50 percent of the global burden of the coronavirus is in Europe, where almost a million cases have been registered and more than 100,000 people have died.

While the worst of the pandemic seems to be behind China, where the virus first emerged, Wuhan figures jumped up 50 percent last Friday, when authorities recounted 1,290 additional deaths of people who had died at home before reaching hospital.

Yet, the US is still in the acceleration phase and registers the largest number of coronavirus cases worldwide - and the hardest-hit city in the world is currently New York.

Successful lockdowns

"The storm clouds of this pandemic still hang heavily over the European region," warned the European director of the World Health Organisation, Hans Kluge, last week as countries start to ease restrictions.

Italy and Spain are the most-affected countries in the region, followed by Germany, France, and the United Kingdom.

Notably, Italy has managed to slow the rate of new cases of Covid-19 after more than a month under a nationwide lockdown, while the total of new confirmed cases indicates that Italy seems to have successfully flattened the curve.

The number of daily coronavirus deaths peaked on 27 March. Both daily new cases and deaths have declined since then.

Although Spain has been criticised for having a slow response to the pandemic, the most affected country in Europe seems also to be bending the curve.

Spain's peak day for coronavirus deaths was registered on 2 April - a week after daily deaths decreased by about 34 percent.

Likewise, improvements have been registered in countries such as Austria and Denmark, as well as in the Netherlands and Belgium.

Meanwhile, Belgian prime minister Sophie Wilmès was obliged to explain last week why the country of 11.5m inhabitants presents one of the highest death tolls in Europe.

The Belgian government "made the choice of full transparency when communicating deaths linked to Covid-19," she said.

Blurry numbers

In fact, the total amount of Belgian fatalities includes also suspected deaths linked to the coronavirus even if they have not been proven by a test.

"In Europe, no country counts like others. We have the most detailed method," the Belgian health minister Maggie De Block told LN24 broadcaster.

There was a similar situation in Spain until last Friday, when the Spanish government decided that the regional authorities must register only the number of cases and deaths proven by tests.

Another complicating factor is the total number of infected people, as many are not tested and others do not present symptoms.

As a result, determining how deadly the virus is remains an open question for epidemiologists, who expect new waves that might last into 2022.

"Currently, we have a huge bias in the numbers coming from different countries - therefore the data are not directly comparable," the director of the Institute of Epidemiology and Medical Biometry at the University of Ulm in Germany, Dietrich Rothenbacher, told the BBC.

"What we need to really have valid and comparable numbers would be a defined and systematic way to choose a representative sampling frame," he added.

At the same time, data indicates how European countries are trying to scale up their testing capabilities as part of their public health strategies.