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Covid-19 Infection & Mortality Rates Can Be Misleading
A single figure for each remains elusive and won’t reflect the true reality anyway
Roughly five months after a novel coronavirus emerged in humans and brought us Covid-19, two of the most important questions have yet to be answered:
- How infectious is it?
- How deadly is it?
Since an unknown number of people have been infected but not tested—either because they had no symptoms, or their symptoms were mild, or tests weren’t possible—the math needed to answer these questions can’t be done. In that vacuum, estimates have emerged.
But the questions themselves are incomplete and the single-number estimates often cited don’t begin to tell the whole story of Covid-19’s ability to spread and kill people. Rather, the disease’s transmissibility and death rate need to be looked at situationally.
Reproduction number
Infectiousness, or transmissibility, is measured, in part, by a reproduction number (called R0 and pronounced “R naught”) indicating the average number of new cases a typical infected person will cause. If R0 is below 1, the number of new cases should decline and a disease will peter out. An R0 above 1 suggests the number of new cases…
