Definitions

Total Cases = reported total cumulative count of detected and laboratory (and sometimes, depending on the country reporting them and the criteria adopted at the time, also clinically) confirmed positive and sometimes - depending on the country reporting standards - also presumptive, suspect, or probable cases of detected infection. Because it represents a cumulative count (rather than a snapshot of the number of current cases at any given time), this number can't decrease. The size of the gap between detected (whether confirmed, suspect or probable) and reported cases versus actual cases will depend on the number of tests performed and on the country's transparency in reporting. Most estimates have put the number of undetected cases at several multiples of detected cases.

Active Cases = (total cases) - (total deaths) - (recovered). This figure represents the current number of people detected and confirmed to be infected with the virus. This figure can increase or decrease, and represents an important metric for Public Health and Emergency response authorities when assessing hospitalization needs versus capacity.

Recoveries = this statistic is highly imperfect, because reporting can be missing, incomplete, incorrect, based on different definitions, or dated (or a combination of all of these) for many governments, both at the local and national level, sometimes with differences between states within the same country or counties within the same state. WHO recommends following the criteria of [symptoms resolve + 2 negative tests within 24 hours] or [symptoms resolve + additional 14 days], but this is only a recommendation. In some countries, when a patient is discharged from the hospital it is counted as "recovered" even if no test is performed. Some health officials now consider anyone who was diagnosed with COVID-19 three or more weeks ago and has not died to be recovered from the disease. In view of this, "Active Cases" and "Closed Cases Outcome" which both depend on the number of recoveries (in addition to an accurate death count and a satisfactory rate of case detection, both of which are lacking in the vast majority of countries) can be affected by this inherent flaw for many countries and for the total worldwide count.

Serious and Critical = similarly to recoveries, it is very imperfect, for many of the same reasons. When 99% of the cases were in China, the figure pretty much corresponded to the Chinese NHC's reported number of "severe" cases. Today, it represents for the most part the number of patients currently being treated in Intensive Care Unit (ICU), if and when this figure is reported.

Total Deaths = cumulative number of deaths among detected cases.