The COVID-19 Omicron Variant

On Nov. 26, 2021, the World Health Organization (WHO) named the Omicron mutation of the COVID-19 virus a variant of concern. Experts first found this variant in specimens from Botswana in early November. The CDC believes that any person infected with Omicron can spread the virus, regardless of their vaccination status or symptoms.

What Are the Symptoms of Omicron?

In early studies, TheBritish Medical Journal (The BMJ) found that cold-like symptoms were common in those with Omicron. They reported that the top five symptoms related to the variant were:

But other common COVID-19 symptoms, like cough, fever, and loss of smell or taste, are still important signs to watch out for with the Omicron variant.

WHO experts have said there isn’t any data that suggests Omicron causes symptoms that are different from the ones produced by other COVID-19 variants.

How Severe Is Omicron?

Experts don’t yet know if Omicron causes more severe disease compared to previous variants. The first reported cases were from university students who were younger and tended to have mild symptoms. But researchers need more data to understand how Omicron affects different groups of people.

This is especially true for instances of reinfection or breakthrough cases in people who are fully vaccinated. One early study has found that a previous infection only gives a 19% protection rate. It puts the chances of getting re-infected at almost 5½ times higher with this variant than with the Delta variant.

It’s important to remember that even a relatively mild case of COVID-19 can cause “long-haul COVID”: symptoms that last for weeks or months after the first illness has passed.

How Quickly Does Omicron Spread?

It’s likely that Omicron spreads more easily than the original COVID-19 virus. But experts don’t yet know if it’s more contagious than more recent variants, like Delta.

One study suggests that the incubation period for Omicron ranges from 0 to 8 days, with a median of 3 days.

What Do We Know About ‘Stealth’ Omicron, or Omicron BA.2?

Scientists call it Omicron BA.2, as opposed to the original Omicron variant, which they call BA.1. At first, scientists thought BA.2 wasn’t as contagious as BA.1 and would fade away soon. That didn’t happen. Starting in January 2022, BA.2 appeared to be at least as easy to transmit as its cousin, BA.1.


A January 2022 study in Denmark showed no difference in the number of hospitalizations caused by BA.2, when compared to BA.1. It also showed that as BA.2 cases went up, BA.1 cases went down. But other countries (Great Britain, Norway, and Sweden) report slower BA.2 increases.

Early studies show that current vaccines and boosters seem to work at least as well against the new Omicron variant, protecting against a first infection as well as against serious illness if you do get infected.

How Do Doctors Diagnose Omicron?

To find out if you have the virus, you’ll need to take a COVID-19 test. You can access at-home tests or see a doctor to get one. If you test positive, more testing would be needed to tell if your case was caused by the Omicron variant. But this process takes a long time and is expensive. Experts don’t usually do it for each positive COVID-19 case. The tests are also done anonymously to protect people’s privacy, so you won’t get that information.

How Do Doctors Treat Omicron?

Researchers continue to look at how well current COVID-19 treatments help with Omicron cases. Because of the genetic changes in the Omicron variant, some treatments will continue to be effective while others may be less useful.

Corticosteroids and IL6 receptor blockers still help people with severe COVID-19 infections.

Does the COVID-19 Vaccine Protect Against Omicron?

Breakthrough cases of Omicron in people who are fully vaccinated are likely. But experts believe that the COVID-19 vaccine will still protect you against serious illness, hospitalization, and death after infection with this variant. Because of this, it’s important to get your COVID-19 vaccine and boosters.

How Can You Prevent Omicron?

There are many things you can do to protect yourself from Omicron and other COVID-19 variants:

Get vaccinated. Vaccines are still the best public health step to protect people from serious illness from COVID-19.

Wear a mask. Your mask will protect you and those around you from all variants. The CDC suggests that you wear a mask in public indoor areas, regardless of if you’ve had the COVID-19 vaccine or not.

Social distance. It’s important to continue to social distance to stop the spread of Omicron.

Get a test. Self-tests or tests given by medical professionals can tell you if you have COVID-19 or not. These tools can help you take steps to protect others from Omicron and other variants.

Other safety measures. Open your windows to improve ventilation, keep your hands clean, stay away from crowded or poorly ventilated areas, and cough or sneeze into your elbow or a tissue.

WebMD Medical Reference Reviewed by Neha Pathak, MD on December 27, 2021



CDC: “About Variants.”

World Health Organization: “Update on Omicron.”

The British Medical Journal: “Covid-19: Runny nose, headache, and fatigue are commonest symptoms of omicron, early data show.”

Eurosurveillance: “Outbreak caused by the SARS-CoV-2 Omicron variant in Norway, November to December 2021.”

University of Minnesota Center for Infectious Disease Research and Policy: “Uncertainty swirls around Omicron COVID-19 severity.”

University Hospitals Cleveland: “Long-Haul COVID-19: Lingering Health Problems Even With Mild Symptoms.” “A second version of omicron is spreading. Here's why scientists are on alert.”

UK Health Security Agency: “COVID-19 vaccine surveillance report Week 4.”

Statens Serum Institut: “Now, an Omicron variant, BA.2, accounts for almost half of all Danish Omicron-cases.”

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