Chapter 1.1: Terminology¶
Number of confirmed cases:¶
The number of confirmed cases is the number of positive viral COVID 19 tests. It’s entirely dependent on the number of tests administered. There are also antibody tests that determine if an individual has ever been infected with COVID 19, but later I’ll discuss why antibody test results are not included in this number.
Number of deaths:¶
The provisional death count, as determined by the CDC, is the number of deaths where COVID 19 was listed as a cause of death, or a ‘presumed’ cause of death. The difficulty in reporting a death due to COVID 19 lies in determining if someone has died due to COVID 19 vs someone who died with the virus. For example, a patient can be infected with the virus, which leads them to develop pneumonia, and they may eventually die of acute respiratory distress caused by pneumonia. In this case, COVID 19 would be listed as a cause of death, despite acute respiratory distress being the ultimate killer. The death reporting issue is further exacerbated by the shortage of COVID 19 tests and forensic pathologists. For this reason, there is the option for medical examiners to declare a probably or presumed cause of death, based on pre-death symptoms and medical records. The total death count for COVID 19 includes both. Granted, death reporting varies by state: some report weekly, others daily, and there are often different methods for determining cause of death. Death reporting is also hampered by different levels of social isolation due to social distancing protocols. The death of someone who lives alone may not be reported for days or even weeks.
Number of true infections:¶
The number of true infections is the number of people who are infected with COVID 19. Without testing the entire population, this number is always an estimate. In this book, the number of true infections will be estimated using some metric.
Why are “confirmed cases” a poor metric for evaluating the state of the pandemic?¶
As I began researching statistics on the virus, I realized that confirmed case counts are a very poor metric for evaluating the state of COVID 19. Research shows that a substantial portion of COVID infections are asymptomatic. This means that people may be infected with COVID without exhibiting any physical symptoms or signs. In fact, as much as 80% of infected individuals are asymptomatic according to the CDC. With limited testing kits, especially in the early stages of the pandemic, there is little reason for doctors to test seemingly healthy individuals. Thus, the number of confirmed cases fails to include a substantial group of infected individuals. Furthermore, case counting is not standardized across states and counties, and different locations will have different levels of resources for such testing to take place.