What we know about the symptoms — and the severity — of the omicron variant

When it was discovered, omicron alarmed scientists. The variant looked wildly different from earlier versions of the coronavirus — and it quickly became clear that these mutations gave omicron an uncanny ability to sidestep our vaccines and spread very rapidly. But it has taken longer to untangle what, if anything, sets an omicron illness apart from that of its predecessors. And most of all, does this variant cause less severe disease than the variants that have come before it? With infections at all-time highs in the U.S., the clinical picture is now coming together and starting to confirm what other countries have found — a typical case of omicron not only presents slightly differently but also likely carries a lower chance of getting seriously ill. Scientists at Case Western Reserve University have preliminary evidence that the risk of being admitted to the hospital or the intensive care unit during the omicron surge in the U.S. is about half of the risk observed during the delta surge. And this reflects what doctors across the country are now seeing firsthand with their patients. "This is a pretty different surge," says Dr. Brendan Carr, chair of emergency medicine for the Mount Sinai Health System — where the emergency rooms are busier than ever but many of the COVID-19 patients are not sick enough to be admitted. But as with any variant of SARS-CoV-2, your absolute risk depends on many factors, including whether you're vaccinated and boosted, your age, your overall health and your economic situation. "In the older age group, it's still a nasty disease, even if it's less [nasty] than the delta variant," says Dr. Pamela Davis, who's a pulmonologist at Case Western Reserve University and a senior author on the new study. "You don't get off scot-free just because you happen to be infected in the time of omicron." "While omicron does appear to be less severe compared to delta, especially in those vaccinated, it does not mean it should be categorized as 'mild,' " said the World Health Organization's director-general, Tedros Adhanom Ghebreyesus, on Thursday. "Just like previous variants, omicron is hospitalizing people and it is killing people." Indeed, hospitalizations across the U.S. now stand at more than 126,000, and more than 1 in every 4 ICU beds is filled with a COVID-19 patient, according to the latest data from the Department of Health and Human Services. When you get sick with omicron, what are the symptoms? "It's mostly that runny nose, sore throat and nasal congestion," says Dr. John Vanchiere, the associate director of the Center for Emerging Viral Threats at LSU Health Shreveport. "The cough is milder [than previous variants], if there's any cough at all, and fever seems to be a little less common." This fits with early data from the U.K. showing that fever and cough are not as prevalent with omicron cases there and that the five top symptoms are runny nose, headache, fatigue, sneezing and sore throat. With omicron, the symptoms also come on more quickly once you're infected. Several studies have found that the incubation period — the time it takes to develop symptoms after being exposed — is about three days. In contrast, delta took about four days, and the original variant took more than five. Another difference doctors are noticing: Loss of smell and taste — considered a telltale sign of COVID-19 — is not nearly as common with omicron infections. And fewer patients have symptoms related to lower respiratory problems, such as shortness of breath, says Vanchiere, including older patients. At the same time, it appears — anecdotally at least — that certain symptoms show up more with omicron than they did with delta. Three that have gained attention are nausea, night sweats and lower back pain. But it's very possible that doctors and patients are simply paying more attention to these symptoms than they did with earlier variants, says Dr. Scott Roberts, an assistant professor of infectious diseases at the Yale School of Medicine. "A lot of this is probably magnifying these symptoms under a microscope instead of clear changes," he says. "Omicron versus delta are really more similar than they are different." And just like earlier variants, omicron can't be defined as causing only a narrow group of symptoms. As at earlier stages in the pandemic, many patients are still having some combination of fever, gastrointestinal problems, aches and pains, brain fog, weakness and, less often, trouble breathing, says Mount Sinai's Carr. "Omicron can present in a myriad of different ways," he says. It's also still not clear how much vaccines and prior infections are responsible for some of these early clinical impressions that omicron is causing a milder constellation of Copyright 2022 NPR. To see more, visit NPR.