Full hospitals, mild cases: What an Omicron wave could look like in the US this winter

• The Omicron variant could become dominant in the US this winter, some disease experts predict.
• An Omicron wave may bring mild cases, but lead to more hospitalizations, early data suggests.

With Omicron cases doubling roughly every two days, US public-health officials are bracing for another wave of coronavirus infections this winter.

"We expect to see the proportion of Omicron cases here in the United States continue to grow in the coming weeks," Rochelle Walensky, director of the Centers of Disease Control and Prevention (CDC), said at a White House briefing on Wednesday.

The CDC's latest model suggests that overall COVID-19 cases will rise in the next few weeks, with the country reporting more than 1 million cases alone in the week leading up to Christmas. COVID-19 deaths could increase in the coming month as well. The CDC model anticipates more than 40,000 new COVID-19 deaths by January 8.

Omicron's ascent comes at an unfortunate moment in the pandemic: Americans are traveling and gathering indoors for the holidays, and in many parts of the country, outdoor activities are limited by cold weather.

Those are ideal conditions for the virus to spread — especially since Omicron seems more transmissible than other coronavirus variants.

"There's a very, very good chance that it's going to become the dominant strain — probably by early next year," Dr. Vivek Cherian, a Chicago-based internal-medicine physician, told Insider.

An Omicron wave may look slightly different than its predecessors: Early data suggests that Omicron produces milder cases compared with other variants, meaning many fully vaccinated and boosted people could expect relatively minor symptoms, such as a cough, fatigue, congestion, or runny nose.

"Most people will have thought they had a bad cold," Tim Spector, the principal investigator of the Zoe COVID Study in the UK, previously told Insider.

But hospitalizations are likely to tick up again as more people get infected — especially unvaccinated, immunocompromised, or partially vaccinated people.

Omicron cases appear milder — perhaps because vaccines are working

Early lab studies suggest that Omicron increases the risk of reinfection relative to other variants and is better than the original virus at evading antibodies from two vaccine doses. But lab studies also suggest that booster shots restore some of that protection, and that two vaccine doses generally ward off severe disease.

Those results may hold true in the real world, according to a new study from South Africa's largest private health insurance administrator, Discovery Health. The study found that two doses of Pfizer's vaccine were 70% effective at preventing Omicron hospitalizations and 33% effective at preventing Omicron infections, based on a sample of around 78,000 Omicron tests.

On Friday, a report from the UK Health Security Agency suggested that a booster dose raised that protection to 70%-75% against symptomatic disease.

Some researchers suspect that vaccines are responsible for the milder disease seen among people infected with the variant in South Africa and Europe. A prior coronavirus infection may also confer some level of protection against Omicron, according to a small lab study published last week.

Patients in South Africa "tend to be getting less sick," Cherian said. "The question is, though: Is that because the strain truly is less virulent or is that because so many people in that population have already become infected and they already have a degree of protection?"

Either way, reports of mild cases have left some disease experts optimistic about the Omicron wave in the US.

"I don't think it's going to cause a lot more people to get really sick, so I personally don't feel like we need to be panicking and hoarding toilet paper again," David Dowdy, an epidemiologist at the Johns Hopkins Bloomberg School of Public Health, told Insider.

Rising cases could ultimately strain hospital capacity

Other experts argue that hospitalizations and deaths are likely to rise the more Omicron spreads.

"Even in my own hospitals that I work at, we're already starting to see more and more cases of COVID," Cherian said. He cautioned that doctors don't know whether cases are Delta, which represents 96% of COVID-19 cases in the US, or Omicron, which represents just 3%.

"As always, the individuals who are the most sick are the people who are unvaccinated, but we are getting individuals who are coming in more and more who have been vaccinated," Cherian said.

By next month, hospitals could experience some of the same capacity issues that they saw at the start of the pandemic, Faheem Younus, chief of infectious diseases at the University of Maryland Upper Chesapeake Health, told Insider.

"Even if Omicron does not overtake the Delta variant, we have enough unvaccinated and vulnerable people in our communities that a post-new year surge is very likely," he said. "Hospital capacity is already strained in many states. We fear a repeat of early 2020 when surgeries were canceled and non-COVID care was impacted due to hospitals being overloaded with COVID."

Staffing shortages at hospitals could make it even more difficult to treat patients. But on the bright side, Younus said, the US has several tools to prevent people from getting severely ill.

"We know the science of this virus, we have adequate PPE, we have ample vaccines and therapeutics," he said, adding, "Severe COVID in America is now largely a choice. I hope we make good choices."

Hilary Brueck contributed reporting.