Our Most Reliable Pandemic Number Is Losing Meaning
A new study suggests that almost half of those hospitalized with COVID-19 have mild or asymptomatic cases.
At least 12,000 Americans have already died from COVID-19 this month, as the country inches through its latest surge in cases. But another worrying statistic is often cited to depict the dangers of this moment: The number of patients hospitalized with COVID-19 in the United States right now is as high as it has been since the beginning of February. It’s even worse in certain places: Some states, including Arkansas and Oregon, recently saw their COVID hospitalizations rise to higher levels than at any prior stage of the pandemic. But how much do those latter figures really tell us?
From the start, COVID hospitalizations have served as a vital metric for tracking the risks posed by the disease. Last winter, this magazine described it as “the most reliable pandemic number,” while Vox quoted the cardiologist Eric Topol as saying that it’s “the best indicator of where we are.” On the one hand, death counts offer finality, but they’re a lagging signal and don’t account for people who suffered from significant illness but survived. Case counts, on the other hand, depend on which and how many people happen to get tested. Presumably, hospitalization numbers provide a more stable and reliable gauge of the pandemic’s true toll, in terms of severe disease. But a new, nationwide study of hospitalization records, released as a preprint today (and not yet formally peer reviewed), suggests that the meaning of this gauge can easily be misinterpreted—and that it has been shifting over time.