person in a medical lab holding a vial with the words Omicron Variant over the image

We will update this post as news comes out about Omicron variants. This post was last updated on July 18, 2022.

The COVID-19 Omicron variant, or B.1.1.529, was first identified on Nov. 24, 2021. Eight days later, the first confirmed case in the United States was reported. The U.S. Centers for Disease Control and Prevention (CDC) has classified Omicron as a variant of concern.

Since then, COVID-19 Omicron sublineages (or subvariants) have emerged.

  • Omicron BA.1 subvariant – this accounted for the widespread surge in COVID-19 cases in December 2021 and the early part of 2022.
  • Omicron BA.2 subvariant – the dominant U.S. variant in spring 2022.
  • Omicron BA.3 subvariant – rare cases in isolated countries, but not in the U.S.
  • Omicron BA.4 subvariant – started to spread in June 2022
  • Omicron BA.5 subvariant – the dominant U.S. variant in summer 2022, accounting for more than 50% of infections
  • Omicron XE subvariant – a recombinant variant, with reports of a handful of cases in the U.S.

According to the U.S. Centers for Disease Control and Prevention (CDC), Omicron can cause more infections and spread faster than the original COVID-19 strain. It also spreads more easily than the Delta variant of COVID-19.

In general, Omicron tends to cause milder symptoms than the original COVID-19 strain, CDC says. It also tends to cause less severe symptoms than the Delta variant. Researchers believe Omicron impacts the airways more than the lungs. It replicates at a slower rate in the body, which results in milder illness.

Some people, including those with moderate to severe asthma or COPD, may develop severe illness if infected with Omicron. They could be hospitalized or die from Omicron infection.

It remains important to protect yourself from COVID-19. Vaccinations and booster shots are widely available. These can significantly reduce your chances of severe illness, hospitalization or death due to COVID-19. If you have asthma or COPD, you may want to continue to maintain distance from other people and wear face masks when around other people, especially indoors.

The more people who are vaccinated, the less the opportunity for the virus to spread and/or mutate into another variant.

What is the BA.5 Omicron variant of COVID-19?

The Omicron BA.2 variant is the latest COVID-19 to spread rapidly around the world. Researchers say BA.5 appears to be the most contagious version yet of the coronavirus.

BA.5 is effective at evading immunity antibodies developed from vaccinations and prior infections. This can lead to more people who have already had COVID-19 getting reinfected with the virus. One study revealed BA.4 and BA.5 are four times more resistant to mRNA vaccines than previous versions of the Omicron variant.

The good news is the Omicron BA.5 variant is not more severe than other variants. Despite its ability to evade antibodies from mRNA vaccines, vaccinations and booster shots can still help reduce the risk of severe and life-threatening symptoms.

Paxlovid, a COVID-19 antiviral pill, is an approved treatment for people who test positive for BA.5 and are at risk for severe illness. Talk with your doctor about Paxlovid if you test positive for COVID-19.

What are some of the symptoms of BA.5 subvariant of the Omicron variant?

Symptoms of the Omicron BA.5 subvariant are similar to the primary COVID-19 virus and its variants (including other Omicron subvariants). In general, symptoms tend to be less severe in some – but not all – people.

The most reported symptoms are:

  • Runny nose
  • Headache
  • Fatigue
  • Sore throat
  • Fever
  • Coughing and sneezing
  • Shortness of breath
  • Muscle or body aches
  • Nausea or vomiting
  • Diarrhea

In addition, some people who get the Omicron variant are reporting back pain.

Early in the COVID-19 pandemic, loss of taste and smell was commonly reported as a symptom. However, for people who get the Omicron variants, loss of taste and smell is not as common.

COVID-19 tends to run its course in 1-2 weeks.

Are the BA.4 and BA.5 subvariants of the Omicron variant in the United States?

Yes, both the BA.4 and BA.5 subvariants of the Omicron variant are spreading in the United States. In July 2022, BA.4 accounted for about 20% of cases and BA.5 accounted for more than 50% of other cases.

Is there an Omicron variant vaccine?

There is not an Omicron-specific vaccine available at this time. However, Pfizer and Moderna are developing a vaccine that is tailored to the BA.4 and BA.5 Omicron variants. It is expected to be available in the fall.

What is the BA.2 “stealth” Omicron variant of COVID-19?

The Omicron BA.2 variant spread around the world in late winter and spring 2022. It was called a “stealth” variant because it was not easily identified through PCR tests. BA.2 lacks a certain marker that sets it apart from other variants, including Delta.

Scientists believe specific mutations within the Omicron BA.2 variant made it more easier to spread than other variants.

What do we know about the Omicron XE variant so far?

The Omicron XE variant is a combination of the two previous Omicron strains, BA.1 and BA.2. It’s a recombinant variant. This means it contains genetic material from both BA.1 and BA.2. Recombinant variants are not unusual — they happen with many viruses. Most die off quickly.

Scientists believe Omicron XE formed when a person had both the BA.1 and BA.2 strains at the same time. The variant quickly started to spread.

Cases of the Omicron XE variant first emerged around the world starting in January 2022. As of April, cases remain rare.

Researchers continue to study if the Omicron XE variant spreads easily. Initial reports suggest it is at least as transmissible as BA.2. The World Health Organization (WHO) issued a report on April 5 saying Omicron XE was 10% more transmissible than BA.2.

COVID-19 vaccines remain the best defense against all Omicron variants including XE In addition, Paxlovid and molnupiravir are effective against Omicron XE.

Should we be worried about the Omicron XE variant in the United States?

Anytime a new COVID-19 variant emerges and starts spreading is cause for concern.

However, it’s too soon to be concerned about the Omicron XE variant. Researchers continue to investigate the XE variant. They are examining how easily it spreads and the severity of its symptoms.

Some variants die out quickly and never spread. But if XE starts spreading and it’s proven to be more transmissible than other variants, it could take over as the dominant variant.

You should be well protected against any COVID-19 variant if you are vaccinated against COVID-19 and received booster shots. Studies show that people who are fully vaccinated and received their boosters have strong protection against hospitalization.

It also may be advisable to wear a mask when in large groups, especially in indoor public spaces.

Are there any other variants?

COVID-19 is constantly evolving. Variants are a natural progression of any virus. Similar to the flu, there will likely be more variants to emerge as we learn to live with COVID-19. Whether they are severe or not remains to be seen.

CDC is always monitoring COVID-19 variants. Most of them are not a concern. At this time, the only one listed as “Variants of Concern” is:

  • Omicron (B.1.1.529 and BA lineages)

The Delta variant (B.1.617.2 and AY lineages) has been downgraded to “Variant Being Monitored.”

CDC has monitored many other variants since the start of the COVID-19 pandemic. Other variants include Alpha, Beta, Gamma, Epsilon, Iota, Kappa, Zeta and Mu. None of these variants have spread as broadly as Delta and Omicron. CDC continues to monitor them but they are not considered a concern.

Reviewed by:
Bradley Chipps, MD, FACAAI, is a board-certified allergist and pediatric pulmonologist with Capital Allergy and Respiratory Disease Center in Sacramento, California. He earned his medical degree from University of Texas Medical Branch in Galveston in 1972. He is Past President of the American College of Allergy, Asthma and Immunology (ACAAI).

Purvi Parikh, MD, FACAAI, is an adult and pediatric allergist and immunologist at Allergy and Asthma Associates of Murray Hill in New York City. She is on faculty as Clinical Assistant Professor in both departments of Medicine and Pediatrics at New York University School of Medicine.