A recent German study estimated that, globally, infection rates could be 30 to 80 times higher than the official tallies. A Massachusetts study of viral particles in sewage had an even wider range; it estimated that the true number of infections could be from 5 to 250 times higher than the number of confirmed cases.
Even if we’re nowhere near herd immunity, the differences between the low and high end range have vast implications for public health — because they paint very different pictures of both how infectious and how deadly the virus is. At the low end, we’d know that we’d acted in time to significantly slow the spread of the disease, and that a “pump the breaks” strategy would therefore be a feasible response to future outbreaks — and a necessary one, because widespread outbreaks could lead to mass fatalities. (And fatality counts are also fuzzier than one would like, since people dying at home who haven’t been tested won’t get counted in the COVID-19 totals.) At the high end, meanwhile, we reach the opposite conclusion: We acted far too late to restrain the spread of COVID-19, but the virus is far less-deadly than anticipated. If that is the case, the focus going forward should be overwhelmingly on protecting vulnerable populations.