Medical Examiner

COVID Cases Are Rising. COVID Deaths Are Declining. Why?

a woman on a beach blanket with a mask
Diane, a nurse from Houston, Texas, sunbathes at the beach next to her husband, both wearing facemasks, in Miami Beach, Florida. EVA MARIE UZCATEGUI/Getty Images

Cases of coronavirus are increasing in 20 states, with dramatic spikes found in places from Florida to California. Even so, overall deaths due to coronavirus are on the decline in the U.S. Part of that is thanks to how much better things are finally getting in New York, the former national epicenter of the pandemic. But even in some places where cases are spiking, the number of people checking into hospitals and dying of the coronavirus is actually stable, or even going down. What’s going on?

This isn’t as weird as it sounds. We’re in a hellish experiment: The more cases of coronavirus, the better our understanding of how deadly the virus is. Right now, as science journalist Smriti Mallapaty outlines in Nature, estimates for the overall case fatality rate for the coronavirus are converging around 0.5-1 percent. Though some experts think it’s still too early to pin down a range, that number is markedly lower than the early estimates of CFR of 4 percent from Wuhan, China. Why? As total case counts started to include patients with mild or no symptoms, the number of people who were known to survive the virus grew. Beyond an expansion of testing, the CFR can be hard to pin down for another reason, notes Mallapaty—it doesn’t kill people uniformly. It’s easier to survive the virus if you have access to good health care; harder if, say, structural racism denies you good treatment. The virus also affects different groups of people differently—it’s far more deadly to older people, for example.

This all means a spike in coronavirus cases in any particular location doesn’t necessarily lead to more people dying. In fact, if you look at many of the graphs of case counts and deaths on the New York Times’ coronavirus map, the lines are doing different things. In Arizona, as cases rise, deaths are remaining relatively flat, with the highest number of deaths in a day happening back in May. Alabama saw a recent spike in deaths to accompany a jump in cases, but not as big as the spike in death, also back in May, when case counts were relatively low. In Florida, which hit its highest number of cases yesterday (2,783), the death rate appears to be falling slightly.

This could be in part because there is a delay between being diagnosed with the virus, and dying from it; we just have to wait and see on that front. But it’s also because the rate at which people are dying really depends on who in the population is adding to the case count. In at least a couple states, they tend to be younger. In California, where cases are on the rise, almost half of new cases are in people under the age of 34, reports Lisa Krieger in The Mercury News. A month ago, almost half the new cases were in people over the age of 50. Despite an increase in cases, deaths and hospitalizations have been remaining relatively stable in California (hospitalizations rose slightly last weekend). In Florida, people under the age of 18 are twice as likely to test positive compared to adults, as my colleague Molly Olmstead notes. Meanwhile, hospitals in Florida are reporting fewer COVID patients even as the disease spreads. Meanwhile, hospitals in Florida are reporting fewer COVID patients even as the disease spreads. (Update, June 22nd: this was briefly true, but hospitalizations are now on the rise.)

There are a few possible reasons for this shift in age. Maybe young people could be more susceptible, after months of quarantining, to caution fatigue—or at least more likely to act on that fatigue by going to a crowded bar, restaurant, or hanging out with friends. It’s also possible that in some areas, increased testing is reaching more young people than it was previously, catching mild cases that might have been overlooked when it wasn’t easy to pop into an urgent care center and get a nasal swab. This doesn’t mean that we shouldn’t be concerned about spikes. Again, because of a delay between diagnosis and death, we haven’t yet been able to fully evaluate the damage these spikes could cause. More sick young people likely means more sick old people. Young people, of course, suffer from the virus even if they don’t die from it. But in the longer term, it’s also possible that death rates will drop regardless of the age of the people who are infected, as we figure out how to treat the virus. More and more people might weather COVID and survive—but surviving COVID has its own set of consequences.

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