In New York City, more than 11,000 people received a positive diagnosis on Saturday, the largest daily number since the pandemic began, and almost certainly a significant undercount. The new variant is now spreading rapidly across vast swaths of the country, and the footage of long lines at testing sites and record numbers of infected have made the threat far less abstract than it had seemed. Omicron, one Wall Street trader told me, is “not as bad as the initial strain in terms of people getting sick, but if you multiply the numbers by four, five, and you do the math around who’s not vaccinated, that puts the health-care system under stress.” (Why this wasn’t clear to traders last week, when many epidemiologists were making exactly that point, is unclear.)

Take a look at how our economy is structured, and the problems Omicron presents become obvious. About 128 million people work in jobs that require human interaction, as bank tellers, baristas, cashiers, and the like. That makes the service industry by far the largest sector of the economy. “In the larger scheme of things, it’s the inability of the services economy to pick up the pace in a situation where the infection rates are rising. That’s a bigger risk to the first quarter,” said Madhavi Bokil, a senior vice-president at Moody’s Investors Services. The country was already dealing with a persistently high level of cases per day, but a huge spike — even without a correlating rise in hospitalizations and deaths — could depress some portion of the service industry, which was just finding its footing again.