Excess deaths – In any population, actuaries use existing mortality analysis to project expected future deaths in the population. In the current pandemic, many groups have experienced deaths above the expected deaths. These are known as “excess deaths”. In several US states, coroners have found through postmortem tissue analysis that deaths attributed to pulmonary failure are actually COVID-19 deaths. Therefore, in various states, many “excess deaths” are now considered COVID-19 deaths, especially where the listed cause of death appears related COVID-19. The lack of uniform reporting standards and enforcement of those standards by CDC has made the task of data interpretation more difficult.

R0 – Called “R zero” in the US and “R-nought” in the UK, R0 refers to the reproduction rate of the virus – that is, if R0 is greater than 1, the number of new infections is increasing; equal to 1, the number is stable; and less than 1, the number of new infections is decreasing. The basic management tool for a pandemic is to keep R0 below 1; done on a sustained basis, the infection will ultimately die out.