1-in-7 New Yorkers May Have Already Gotten Covid-19 — nearly 1.3 Million New Yorkers — which Means a Mortality Rate of about 1%April 16, 2020
Of the 215 women who delivered babies at New York-Presbyterian Allen Hospital and Columbia University Irving Medical Center in Upper Manhattan from March 22 through April 4, 214 were tested for the coronavirus that causes Covid-19. Thirty-three of them, or more than 15%, tested positive, even though only a few had symptoms. In Gangelt, a German town that makes a big deal out of Karneval (aka Mardi Gras) and had a major coronavirus outbreak after this February’s festivities, 500 residents were tested for evidence of either the virus or the antibodies that indicate one has recovered from it, and 15% of them tested positive as well.
Meanwhile, in Iceland, randomized testing of the population found 0.6% of those tested in late March and early April to have the disease. In San Miguel County in the mountains of Colorado (the ski town of Telluride is the county seat) widespread testing for coronavirus antibodies had as of Tuesday afternoon delivered a 0.6% positive ratio and an additional 1.5% of “borderline” results.
What these preliminary findings (those from New York and Iceland were published in the peer-reviewed New England Journal of Medicine, the German data are from an as-yet-incomplete University of Bonn study and the Colorado numbers are simply posted daily on the county website) seem to show is that in places hit very hard by Covid-19, a surprisingly large number of people have been infected with it, and that in the rest of the world, very few have.
This means that the occasional hopeful suggestions that the coronavirus is already widespread globally and herd immunity will be putting an end to the pandemic any minute now are most likely bunk. But it also means — and this was already the view of pretty much every epidemiologist whose work I have consulted — that the confirmed coronavirus cases reported by governments and tabulated in places like the Johns Hopkins University coronavirus map represent only the tip of the iceberg of actual infections, especially in disease hot spots. Another way of putting it is that if you live in rural Colorado and had a fever in February, that wasn’t the coronavirus. If you live in New York City and had a fever in late March, it probably was.
Out of a population of 8.4 million, New York City had 111,424 confirmed Covid-19 cases as of Tuesday evening. If those pregnant women in Upper Manhattan are representative of the city as a whole, though, nearly 1.3 million New Yorkers have or have had the disease. That in turn implies a ratio of fatalities to infections of about 1% so far, not the 9.8% one gets dividing deaths by confirmed cases.