Four years ago, at the beginning of the pandemic, scientists expected the virus would be well on its way to settling into a seasonal pattern by now, said Talia Quandelacy, an assistant professor of epidemiology at the Colorado School of Public Health. Now, they’re less sure whether COVID-19 will eventually do that, or if it can keep churning out new variants fast enough to remain active year-round, she said. “That’s one of the big questions in the field,” she said.