Omicron drives U.S. COVID-19 cases past delta's peak

The omicron variant, which is now dominant in the United States and spreading faster than any variant yet, has already pushed daily coronavirus case counts higher than the peak of the recent delta wave. By most estimates, the country is in for a significant winter surge.

Although there are early positive signs out of South Africa and Britain that omicron infections more often result in mild illness than previous variants, officials are warning that the new variant could swiftly overtax the health care system and bring significant disease to many communities.

Omicron is spreading fast.

The highly transmissible variant is causing near-vertical case growth in multiple U.S. cities, with figures doubling about every two to three days. Officials expect it to break records. The high for average daily cases was 251,232, set in January. By some estimates, the United States could reach 1 million cases a day, even before the end of the year.

While omicron's speed now speaks for itself, scientists are still racing to understand its threat. Preliminary studies out of Scotland and England suggest that infections from the variant could be milder, but scientists caution that omicron infections must be observed in the U.S. population before drawing conclusions.

Even if these early results hold and omicron does cause mostly mild illness, the sheer magnitude of cases it causes could still escalate hospitalizations at a time when many medical centers are already full.

"When we have millions and millions and millions of people, all sick, all together at one time, it doesn't take a large percentage of those people to topple over the hospitals," said Dr. Hallie Prescott, associate professor of internal medicine at the University of Michigan.

Hospitals are already strained.

Hospitals across the country are close to brimming, their care wards filled with patients who have been ill with delta or delayed treatments for so long during the pandemic that they now need critical care. About 1 in 10 hospital service areas, scattered all over the United States, have had their intensive care units at more than 90% capacity in recent weeks.

"We have patients who are waiting in the emergency department for ICU care, so we are providing ICU care in the emergency department," said Dr. Dani Hackner, chief clinical officer of the Southcoast Hospital Group in southeastern Massachusetts, which has postponed elective surgeries to relieve pressure on its medical centers.

"I do think the coming month is going to be a very tough month," he added.

Hospital administrators say nurses and doctors are overwhelmed and exhausted and that staffing shortages are making matters worse. Several states, including Minnesota and Massachusetts, have called on the National Guard to provide extra support, and President Joe Biden recently announced he would direct more military personnel to assist overtaxed hospitals.

Not enough people are boosted, or vaccinated at all.

Public health experts are worried the millions of unvaccinated or not-yet-boosted Americans are vulnerable as omicron spreads. The variant is thought to evade immunity from both vaccination and prior infection, but early research suggests a booster provides the best protection against infection. And vaccination, even without the booster, is expected to maintain strong protection against hospitalization and death.

Across the United States, nearly 62% of all people have been fully vaccinated and about 19% have received an additional booster dose, though not everyone is eligible yet. The coverage rates vary widely by state, with some of the lowest levels found in the South. The United States overall lags behind many other nations, in part because of vaccine hesitancy.

Booster rates are also low because the rollout is just getting started. Adults and teens have been eligible for only a few weeks, and some adults are not aware that the additional shots are strongly recommended.

The Biden administration this week again emphasized the importance of being vaccinated or boosted as the most powerful tool against omicron. Still, researchers say there is significant uncertainty about what omicron will bring in the coming weeks.

"The truth is that we could be looking at a Category 5 hurricane or a tropical storm," said Julie Swann, a professor of industrial and systems engineering at North Carolina State University who was an adviser to the Centers for Disease Control and Prevention during the 2009 H1N1 pandemic. "But we have to prepare for the possibility of that Category 5 hurricane."

This article originally appeared in The New York Times.