“…7 , 10 , 11 , 12 One study estimated infections in the USA and other select countries, 13 and other studies have done multinational systematic reviews and meta-analyses of seroprevalence surveys. 14 , 15 The fundamental problem in all of these analyses is that each of the data series observed has potential biases: reported cases capture only a portion of infections, and this portion will be a function of the availability of testing; reported deaths capture only a subset of total COVID-19 deaths, and the infection–fatality ratio (IFR) can vary widely over time and across locations; 16 , 17 , 18 , 19 the proportion of patients with an infection who are admitted to hospital can also vary over time and location; and seroprevalence surveys can be influenced by sampling design, waning of sensitivity of antibody tests, and vaccination rates. Few studies have combined data from reported cases, reported deaths, hospitalisations, and seroprevalence surveys to triangulate daily infections, and WHO only routinely reports confirmed cases, not estimated infections.…”