What Are the Symptoms of Omicron?

Omicron has become the dominant variant of the coronavirus in the U.S. Our understanding of the variant continues to evolve, but we know more about Omicron now than we did when it first appeared—including its symptoms.

So far, research shows that it’s more transmissible and causes less severe disease than earlier variants, like Delta. Symptoms of Omicron infection may be different, too.

Peter Gulick, DO, an associate professor of medicine at Michigan State University, told Verywell that the symptoms of Omicron mainly remain in the upper respiratory tract and can include a sore throat, congestion, runny nose and headache. “Occasionally there can be nausea and diarrhea,” Gulick said. Other people may have muscle aches, fever and chills.

December data from the ZOE COVID Study app, a global initiative to track COVID cases and symptoms, adds fatigue and sneezing to the list of common Omicron symptoms.

In earlier variants, infection caused more harm to the lungs.

The good news is that overall, Omicron is milder than Delta in both vaccinated and unvaccinated people, Gulick says. “About 90% of those hospitalized are unvaccinated,” he said. 

A problem, however, is that Omicron’s symptoms can overlap with that of the common cold and flu. In the winter, when we experience cold and flu season, it can be hard to differentiate a COVID infection from other viruses.

“Symptoms of loss of taste and smell are related to COVID, so if you develop symptoms and are at high-risk, then definitely get tested since there is now treatment for early disease,” Gulick said. “If symptoms, like coughing, are bad, seek medical help.”

People Should Still Be Vigilant 

Even if Omicron can feel like "just a cold” to those fully vaccinated, it is much more transmissible. This means people are at a higher risk of reinfection. Gulick says that even for those who are vaccinated, a reinfection rate may be as high as 30%.

“You need to be cautious—even though for most people who are vaccinated with a booster, they will likely experience only a mild disease," he said. 

We also need to keep in mind the true definition of “mild,” Hilary Babcock, MD, a professor of medicine who specializes in prevention of infection transmission at Washington University School of Medicine in St. Louis, told Verywell. In the world of infectious disease and epidemiology, mild doesn’t always mean sniffles; the marker of a mild disease is whether or not people end up in the hospital.

“A mild infection then could still leave you with a high fever, chills and muscle aches, and kind of knock you out for a few days,” she said. “That would still be considered a mild infection… it could be a more significant illness, but just not severe enough to end up in the hospital.”

Of course, people at higher risk of serious illness can still face more dire health outcomes—even if they are vaccinated. Gulick says people who are over 65 years old, those who are immunocompromised, and those with comorbidities such as obesity, diabetes, and hypertension, can still get seriously ill.

This is why getting booster shots, as well as flu shots, masking, and getting tested remain important, he says.

What About Long COVID?

We are also still learning about long COVID. Babcock says Omicron hasn’t been around long enough yet to have a good sense of whether it is different from earlier variants when it comes to the likelihood of lingering symptoms. 

While the research continues to evolve, so far, it shows that vaccinated people are less likely to go on and have long COVID. Babcock says that new data shows that people who were vaccinated and got infected with a previous variant of the virus had a much lower risk of long COVID than unvaccinated people who got infected.

“That's great data because it shows that vaccination is protective, not just against getting infected and ending up in the hospital and dying—all of which are really good benefits—but also, your risk of getting long COVID is much lower if you are vaccinated,” she said.

How to Protect Yourself 

As Gulick points out, getting booster shots is crucial. He also says that on top of vaccines, it’s important people wear masks, practice social distancing and avoid indoor crowds whenever possible. Testing, if you suspect you have COVID, can help curb spread and protect others. And if you are sick, or suspect you could be sick, stay home.

Babcock acknowledges that there is social fatigue with the pandemic and its safety precautions—but says they remain important. When we let our guards down and skip out on booster appointments or throw away masks, we are giving the virus more opportunities to spread. 

“Wearing a mask is not really that hard; getting a vaccine and getting a booster is, for most people now, fairly accessible,” she said. “Taking those steps will really help. Even now, for people who haven't gotten vaccinated, they can still benefit from vaccination.”

The information in this article is current as of the date listed, which means newer information may be available when you read this. For the most recent updates on COVID-19, visit our coronavirus news page.