How deadly is the omicron variant? Here's what we know

Early data suggests that omicron variant hospital admissions are the lowest of the four COVID waves

By Nicole Karlis

Senior Writer

Published December 21, 2021 7:01PM (EST)

Coronavirus COVID-19 (Getty Images)
Coronavirus COVID-19 (Getty Images)

On Monday, the Centers for Disease Control and Prevention reported that the omicron variant now accounts for nearly 73 percent of new coronavirus infections in the United States. That rise is astonishing given that, in the beginning of December, the new variant only made up less than 1 percent of new infections. This means that the variant has successfully outcompeted the delta variant, ushering in a new stage of the pandemic scientists long feared would arise.

Currently, much of the country is seeing a dramatic increase in the number of COVID-19 cases thanks to omicron. In New York state, new coronavirus cases have increased more than 80 percent over the last two weeks.

"It is a predictor of what the rest of the country will see soon, and the minimum — since NYC is highly vaccinated — of what other parts of the country will experience in under-vaccinated cities and states," Georges Benjamin, executive director of the American Public Health Association, told Reuters.

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While the country now has to brace for a surge in cases due to a more transmissible variant, it is likely not only unvaccinated people who will be affected. As reported by the New York Times, the country should also prepare for a rise in breakthrough infections, or infections despite vaccination. That is because, as Salon has previously reported, omicron is unique in the sense that compared to previous variants, it has the highest number of mutations reported — mutations that can partially evade vaccine-based immunity.

Indeed, out of nearly 50 mutations observed in the omicron variant compared to the original virus, 32 are in the spike protein, which implicates the virus' ability to attach and gain entry into human cells.

But that doesn't mean the vaccines don't provide some protection; rather, they are still overwhelmingly effective at preventing severe cases and death. Still, omicron's rapid rise leaves one big, open-ended question: How severe is the disease caused by omicron? And can we expect a rise in hospitalizations and deaths, or can we just expect many (albeit mild) infections?

The answer to these questions will affect how cities and states across the country respond to omicron. And the short, unsatisfying answer is scientists just don't have one. Yet new data on the horizon continues to suggest that omicron is indeed less severe — which, if continually proven true, is the best possible outcome. 

"There are definitely signals that the severity level of omicron may be different than delta and other variants," Dr. Amesh Adalja, a senior scholar at the Johns Hopkins Center, tells Salon. As a caveat, Adalja noted that "much of this data is derived from South Africa," which has different herd immunity levels than the United States.

Omicron was first reported by scientists in South Africa who noticed an increase in cases in the Gauteng province. In a large study presented by the South African Medical Research Council in collaboration with Discovery Health, a large health insurance company, researchers analyzed more than 200,000 COVID-19 cases in South Africa during a delta-driven surge in September and October and the beginning of the omicron surge in November. Nearly 25 percent of cases analyzed were made up of people who had a chronic illness, which put them at a higher risk of COVID-19.

Notably, researchers in this study found that the risk of hospitalization dropped nearly 30 percent during the early days of the omicron surge compared to what they saw during the delta-driven surge.

"The hospital admissions during omicron, standing at 58 per 1,000 infections, are the lowest of the four COVID waves, and one-third of what we experienced during the delta surge," Discovery Health CEO Ryan Noach said.

According to the analysis, those who did go to the hospital were not as sick as those who were hospitalized during the delta surge. Not as many people needed oxygen or ventilation.

However, not all experts believe this data to be an accurate indicator regarding the severity of the variant in other countries. In part, that is because people in South Africa have built up strong immunity against COVID-19.

"Omicron enters a South African population with considerably more immunity than any prior SARS-CoV-2 variant," said Dr. Roby Bhattacharyya, an infectious disease specialist, and epidemiologist William Hanage in a paper published online.

However, Dr. Adalja said there is data coming from Denmark that suggests omicron is less severe when compared to delta. While COVID-19 cases are on the rise there, hospitalizations and deaths are low. 

Dr. Monica Gandhi, infectious disease doctor and professor of medicine at the University of California–San Francisco, told Salon she believes there is enough evidence that omicron is less severe than previous variants. Gandhi pointed to data published from the University of Hong Kong last week that stated omicron is less likely to be able to infect lung cells compared to previous variants.

"In the United Kingdom, out of the first 25,000 cases of omicron, about 85 patients had been hospitalized and in Denmark, out of the first 785 cases, 1.15% have been hospitalized, both lower rates than during the delta surges," Gandhi said. "But we do not know yet if this is because of increasing cellular immunity in the population in December 2021 versus an inherent property of the strain that makes it less virulent or both."

Indeed, time will tell — and more research needs to be done to figure out why, at the moment, hospitalizations and deaths are happening at lower rates with omicron.

On Tuesday, the U.S. confirmed the first omicron-related death in Texas. The man between the ages of 50 to 60,  according to a press release from Harris County Public Health, was unvaccinated, had previously been infected with the coronavirus and had an underlying health condition. It is probable that there have been many other deaths from the omicron variant in the United States, as only a handful of patients have the virus' genome sequenced. 

Dr. Adalja cautioned that while omicron is appearing to be less severe, high-risk unvaccinated people are still at risk."

"For those who are high risk and unvaccinated, it still is severe enough to cause hospitalization and death," Adalja said.

Read more on the omicron variant:

By Nicole Karlis

Nicole Karlis is a senior writer at Salon, specializing in health and science. Tweet her @nicolekarlis.

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