One of the major problems with the COVID-19 pandemic is the speed at which the contagion spreads. This makes treating infected people much more difficult to manage, but also severely hinders our ability to have an up-to-date, thorough and trustworthy picture of the situation in Europe and the rest of the world.

The information we rely on is approximate and often errs on the side of caution (for example, the number of infected people, or deaths caused by the pandemic). It’s important to be aware of these limitations, and approach the data with caution, even if this data is the best we have, given the present circumstances. Of all official data on the global situation, that produced by the European Centre for Disease Prevention and Control (ECDC) is considered among the most reliable. Nevertheless, new and more accurate studies are emerging every day, providing additional data to help understand the pandemic and its course of development.

How many are really infected?

We don’t know. What we do know is the number of confirmed infections – individuals testing positive for the virus – and highly approximate estimates of total infections.

The test for the virus involves taking a sample of saliva or mucus, which is then analysed for traces of the virus’ genetic code. The number of people being tested varies widely from country to country : depending, above all, on how well-equipped a country is to perform large-scale testing (often it’s not the kits that are lacking, but the personnel and laboratories required to analyse huge quantities of swabs). In certain countries, authorities decide to focus on people already showing symptoms associated with COVID-19, or even just those who are already hospitalised. We know, however, that many who have contracted the virus do not show any symptoms, or only start to show symptoms many days after being infected.

The percentage of infected people accounted for in the data varies widely from country to country. This makes it difficult to compare the development of the pandemic in different times and places. For example, Italy has performed around 3500 tests for every million inhabitants, compared to 6100 in South Korea, and 600 in Spain. According to an estimate attempted by the Centre for the Mathematical Modelling of Infectious Diseases, in the London School of Hygiene & Tropical Medicine, Italy and Spain may have only recorded 5 percent of people actually infected. 

How many have really died?

This is also unknown, even if the number of deaths can be estimated with more precision than cases of infection.

What we do know is the number of deaths attributed to COVID-19 (unfortunately, the criteria for attribution are not yet internationally standardised ). However, we cannot be sure that all deaths caused by the coronavirus have been recorded: in the most heavily hit areas of Italy, indications suggest that tests are not performed on all victims (many of those who die at home or in retirement homes, for example). Moreover, authoritarian regimes such as China and Iran may have an interest in publishing incomplete data in order to downplay the severity of the problem – thus the number of deaths caused by the pandemic may very well be higher than suggested by official counts.