One month ago, the CDC published the results of more than 20 pandemic forecasting models. Most projected that COVID-19 cases would continue to grow through February, or at least plateau. Instead, COVID-19 is in retreat in America. New daily cases have plunged, and hospitalizations are down almost 50 percent in the past month. This is not an artifact of infrequent testing, since the share of regional daily tests that are coming back positive has declined even more than the number of cases. Some pandemic statistics are foggy, but the current decline of COVID-19 is crystal clear.
What’s behind the change? Americans’ good behavior in the past month has tag-teamed with (mostly) warming weather across the Northern Hemisphere to slow the pandemic’s growth; at the same time, partial immunity and vaccines have reduced the number of viable bodies that would allow the coronavirus to thrive. But the full story is a bit more complex.
Mask and social-distancing thing.
“If I were ranking explanations for the decline in COVID-19, behavior would be No. 1,” says Ali Mokdad, a global-health professor at the University of Washington, in Seattle. “If you look at mobility data the week after Thanksgiving and Christmas, activity went down.”
Other officials have pointed to Google mobility data to argue that Americans withdrew into their homes after the winter holidays and hunkered down during the subsequent spike in cases that grew out of all that yuletide socializing. New hospital admissions for COVID-19 peaked in the second week of January—another sign that social distancing during the coldest month of the year bent the curve.
Our cautious behavior evidently requires the impetus of a terrifying surge. In the spring, southern and western states thought they had avoided the worst of the early wave, and governors refused to issue mask mandates. Then cases spiked in Texas, Florida, and Arizona, and mask-wearing behavior in the South increased. When cases came down again, people relaxed, cases went up again, and the awful do-si-do continued.
The lesson is not to let today’s good news become tomorrow’s bad news, again. Until much of the population is vaccinated, don’t interpret the decline in cases as a green light to resume your pre-pandemic behavior.
