“I personally know several individuals who have had COVID in almost every wave,” says Salim Abdool Karim, a clinical infectious-diseases epidemiologist and the director of the Center for the AIDS Program of Research in South Africa, which has experienced five meticulously tracked surges, and where just one-third of the population is vaccinated. Experts doubt that clip of reinfection—several times a year—will continue over the long term, given the continued ratcheting up of immunity and potential slowdown of variant emergence. But a more sluggish rate would still lead to lots of comeback cases. Aubree Gordon, an epidemiologist at the University of Michigan, told me that her best guess for the future has the virus infiltrating each of us, on average, every three years or so. “Barring some intervention that really changes the landscape,” she said, “we will all get SARS-CoV-2 multiple times in our life.”
If Gordon is right about this thrice(ish)-per-decade pace, that would be on par with what we experience with flu viruses, which scientists estimate hit us about every two to five years, less often in adulthood. It also matches up well with the documented cadence of the four other coronaviruses that seasonally trouble humans, and cause common colds. If SARS-CoV-2 joins this mix of microbes that irk us on an intermittent schedule, we might not have to worry much. The fact that colds, flus, and stomach bugs routinely reinfect hasn’t shredded the social fabric. “For large portions of the population, this is an inconvenience,” Paul Thomas, an immunologist at St. Jude Children’s Research Hospital, in Tennessee, told me. Perhaps, as several experts have posited since the pandemic’s early days, SARS-CoV-2 will just become the fifth cold-causing coronavirus.
Or maybe not. This virus seems capable of tangling into just about every tissue in the body, affecting organs such as the heart, brain, liver, kidneys, and gut; it has already claimed the lives of millions, while saddling countless others with symptoms that can linger for months or years.