I fear people are underestimating the seriousness of the situation by looking at just confirmed cases of COVID-19 but ignoring models which warn that the only reason the numbers are so low is that we lack adequate capability to test people.
New York City passed 4,000 confirmed cases on Thursday. Last Thursday, they had 216 cases. Two weeks ago, they had 11. The number of cases is multiplying 20-fold in a week as the disease spreads and as testing becomes more widely available. It is expected New York City will add 1,000 new confirmed cases on Friday.
(UPDATE 3/20 6:50 PM ET: NYC did in fact add more than 1,000 new confirmed cases, reaching 5,151)
(UPDATE 3/20 8:00 PM ET: NYC actually added more than 4,000 new confirmed cases today, topping 8,000)
If the hospitalizatio rate maintains pace with the infection rate, New York City will run out of available hospital beds on Tuesday.
One model I examined today suggested that when comparing hospitalization rates to infection rates in hard-hit places like South Korea, China, and Italy, it is more likely New York City is adding closer to 25,000 new cases each day now instead of the 1,000 being reported.
This chart shows the actual reported positive tests in New York City in red (barely enough to move the line off the bottom of the graph) and the number of actual infections the forecasting model predicts based on comparing existing data like percentage of tests coming back positive, hospitalization rates, and mortality rates.
Simply put, by the end of next week, New York City could be reporting 10,000 active cases but would really have somewhere around 400,000 cases.
Now, to be clear, this estimate is something between a best-case and worst-case scenario. The author of the study (Michael Donnelly) used data from the New England Journal of Medicine as a basis but had to take plenty of wild guesses as there is no way to know how much we don’t know until the tests start giving more data.
This chart shows how many tests per 1 million of population each country surveyed had completed. Yes, that is the United States down there near the bottom with Thailand and Vietnam.
Nate Silver, who runs the 538 website and builds statistical models for everything from baseball to politics, cautioned Donnelly against making too many assumptions with so many holes in the data but offered the following assessment Thursday evening.
Lombardy is the region in Italy including Milan and Venice which has been devastated by the virus despite a massive quarantine effort.
It is unclear how terrible things are going to get, but one thing is certain, it is going to get worse before it gets better.