COVID-19 numbers and models: misleading us, or leading us outof misery?

Heiko Philippin, Karin M Knoll, David Macleod
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cOVID-19 numbers and statistics have been dominating our news since the beginning of 2020. Although they fail to tell the story of the individual hardship and grief that many are dealing with, they can provide a bigger picture of the situation and assist in planning.


How many people worldwide have been infected with COVID-19?

 A common number which is reported is the count of positive test results for SARS-CoV-2. The number is collected by hospitals, laboratories or individual doctors and sent to national health agencies. A global overview is provided by the World Health Organization ( and other data portals. Newspapers publish daily updates and often countries are compared, or even ranked, by this number. However, this number of positive test results is not the same as the actual number of people infected with SARS-CoV-2. An unknown number of undetected infections exists in every country as:Some people who are infected do not have symptoms and are not testedSome people with symptoms do not have the opportunity to be tested. This could be due to a lack of testing kits or rules about who should be tested (e.g., different age and risk groups), and when they should be tested (e.g., immediately when showing symptoms or when hospitalised for COVID-19).

How many people have died from COVID-19?

International comparisons of the number of COVID-19 deaths can be just as misleading, as countries use different definitions and policies regarding which deceased persons are counted. Some countries include only people who died of COVID-19 in hospital and tested positive for SARS-CoV-2, whereas others also include people who died outside the hospital or were suspected of having COVID-19. These definitions and policies may change over time within a country.The so-called excess mortality can be helpful in finding out about the true impact of COVID-19 on death. Excess mortality looks at the number of additionaldeaths during a certain time period compared to the