What Covid Models Get Wrong
Focus on the burden on hospitals, not on the oft-mistaken forecasts.

Here we go again. The University of Washington’s Institute for Health Metrics and Evaluation has issued a new forecast that Covid-19 fatalities would spike over the summer in states that have moved faster to reopen. Cue the media drumbeat for another lockdown. Maybe someone should first explain why the models were wrong about so much the last time.
Take New York, where Gov. Andrew Cuomo locked down the state in mid-March based on dire warnings. His public health experts projected the state would need as many as 140,000 hospital beds and 40,000 intensive care units—two to three times more regular hospital beds and 10 times more ICU beds than were available. The UW model forecast that 49,000 regular beds and 8,000 ICU beds would be needed at the peak.

New York was hit hard, but Covid-19 hospital bed utilization in New York peaked at 18,825 and 5,225 for ICUs in mid-April. Even in New York City, hospital utilization never exceeded 85% of capacity and 89% for ICUs. Government-run hospitals in low-income neighborhoods with the most cases were unprepared, but they were ill-managed before the pandemic.
New York was the country’s frontline in the coronavirus attack, and caution was needed in the early days because so little was known about the virus. The original UW model, which was based on the experiences in Italy and Wuhan, assumed that strict lockdowns would curb infections, reduce hospitalizations and lower deaths faster than they actually did in the Northeast.
Asked last month about when fatalities and hospitalizations would meet state thresholds for reopening, Mr. Cuomo responded: “All the early national experts, ‘Here’s my projection model.’ . . . They were all wrong. They were all wrong. . . . There are a lot of variables. I understand that. We didn’t know what the social distancing would actually amount to. I get it, but we were all wrong.”
Hospital utilization by Covid-19 patients in New York City has fallen 94% since the peak, which has allowed some non-essential treatments to resume. New York City has 29% of its hospital beds and 34% of its intensive care units now available. New cases have fallen by about 40% and new hospitalizations by a third in the last two weeks, despite the recent protests.
Warnings about reopening states are also overblown so far. While Arizona has had an uptick in hospitalizations, about 59% of its emergency beds and 17% of ICU beds are unused. A month ago, 43% of hospitalized patients with Covid were in the ICU. Now only a third are, suggesting that better and earlier treatment is easing disease severity.
In Texas, hospitalizations have also been climbing, but weekly fatalities are down 40% from a month ago. Covid-19 patients occupy fewer than 5% of all hospital beds, and more than a quarter are available. Even in Houston—which has experienced the biggest increase in hospitalizations—Covid-19 patients occupy only 6% of hospital beds. More than 20% are unused.

Covid-19 patients take up a small share of ICU beds in most states that have reopened including California (16%), Texas (11%), Georgia (10%), Utah (9%), Wisconsin (8%) and Florida (7%). Nearly all states have ample hospital and ICU capacity.
California Gov. Gavin Newsom started easing his strict lockdown six weeks ago, and restaurants, hair salons, retail stores and gyms are now allowed open in most counties outside of the Bay Area. While new cases have been rising due to more testing and in some cases from community spread, hospitalizations and fatalities have been flat since early May. In Los Angeles, ICU utilization has fallen by about 15% in the last month.
“We have to recognize you can’t be in a permanent state where people are locked away—for months and months and months and months on end—to see lives and livelihoods completely destroyed, without considering the health impact of those decisions as well,” Mr. Newsom said Monday.
Yet national Democrats and the press are still promoting worst-case predictions, almost as if they’re hoping for worse so they can prove Donald Trump wrong. The University of Washington now projects that reopening will cause deaths to triple in California and increase six-fold in Florida and Arizona through September.

But as Stanford epidemiologist John Ioannidis explains in a new paper, most models have overshot in part by making faulty assumptions about virus reproduction rates and homogenous susceptibility. A Massachusetts General Hospital model predicted more than 23,000 deaths within a month of Georgia reopening but the state had only 896.
“In the presence of strong groupthink and bandwagon effects, modelers may consciously fit their predictions to what is the dominant thinking and expectations—or they may be forced to do so,” Mr. Ioannidis writes. “Forecasts may be more likely to be published or disseminated, if they are more extreme.”
A surge of new infections is inevitable as states reopen, and health officials will have to watch for and contain hot spots. But the Covid models aren’t destiny, and the cost of new lockdowns is too great to sustain. We have to live with the virus risks while fortifying the health system and protecting the most vulnerable.