Tanya Lewis in Scientific American:
All pandemics end eventually. But how, exactly, will we know when the COVID-19 pandemic is really “over”? It turns out the answer to that question may lie more in sociology than epidemiology.
As the world passes the second anniversary of the World Health Organization’s declaration of the COVID pandemic, things seem to be at a turning point. COVID cases and deaths are seeing sustained declines in much of the world, and a large percentage of people are estimated to have some immunity to SARS-CoV-2, the virus that causes the disease, through infection or vaccination. The Centers for Disease Control and Prevention has released new risk metrics that suggest people in many parts of the U.S. no longer need to wear a mask, and mayors, governors and other officials have been dropping mask and vaccine mandates in a push to get back to normal. Although the COVID-causing virus, SARS-CoV-2, is likely to always circulate at some level, there is a growing belief among some people—though not all—that the pandemic’s acute phase may be subsiding.
“I believe that pandemics end partially because humans declare them at an end,” says Marion Dorsey, an associate professor of history at the University of New Hampshire, who studies past pandemics, including the devastating 1918 influenza pandemic. Of course, she notes, there is an epidemiological component, characterized by the point at which a disease still circulates but is no longer causing major peaks in severe illness or death. This is sometimes referred to as the transition from a pandemic disease to an endemic one. But for practical purposes, the question of when this transition occurs largely comes down to human behavior.