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How is Omicron Different? What We Know About the COVID-19 Variant

January 14, 2022
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Throughout the coronavirus pandemic, new COVID-19 variants have emerged – those that the CDC identifies as “variants of concern” include Delta and Omicron. While new variants are expected to happen. There are steps we can take to understand and lower our risk of infection and illness.

What are Variants?

In order to spread, viruses (like COVID-19) constantly make copies of themselves. In the process of duplicating, they sometimes create versions that are not exact copies – these are called mutations. Variants are viruses with mutations. Some variants emerge and then go away, while others stick around and spread. The CDC and other organizations monitor COVID-19 variants as they emerge.

How is Omicron Different?

As of the end of December, the Omicron variant of COVID-19 had been detected in most U.S. states and territories according to the CDC. Dr. Sarah Haessler, hospital epidemiologist at Baystate Health, describes Omicron and discusses how we can reduce the spread of the virus.

“What’s different about Omicron variant is that it did not emerge as a mutation of the Delta variant. This is something that came from the original strain.”

Coming from the original COVID-19 virus strain, Omicron has 30 genetic mutations in it. Dr. Haessler points out that these mutations “make it more contagious and give it a shortened incubation period and more ability to evade our immune protection that we have from natural infections or vaccination.”

How Contagious is Omicron?

Mathematical modeling shows Omicron is 4-70 times more contagious. Every 2-3 days, there are twice as many people infected with Omicron vs previous strains. And before Omicron, COVID’s incubation period (the number of days between when you’re infected and when you see symptoms) was between 4 and 7 days. With Omicron, that incubation period is shortened to 3-4 days. “Some people are contagious within 1 day of exposure,” says Haessler.

Can I Get Infected with Omicron if I am Vaccinated?

While there are breakthrough infections with the Omicron variant (meaning that those vaccinated can be infected), unvaccinated people remain at the highest risk.

What can we do?

1. Get a booster shot

Vaccines protect against severe illness, hospitalizations, and death, even with the Omicron variant. Booster vaccinations make people 25 times more resistant to infection.

You’re eligible for a booster shot if:

  • You are 18 or older and received the Moderna vaccine 5+ months ago
  • You are 12 or older and received the Pfizer vaccine 5+ months ago
  • You are 18 or older and received the Johnson & Johnson vaccine at least 2 months ago

You can find a vaccine or booster shot by visiting or

2. Wear a mask

Studies show that face masks protect you from getting infected and from spreading the virus.

In addition, both the CDC and the Massachusetts Department of Public Health advises everyone to wear a mask or face covering in indoor public places.

3. Practice Physical/social distancing

It is important to remember that people without symptoms may still be able to spread the virus. The CDC recommends staying at least 6 feet from other people, especially if you are at high risk of getting sick. In addition, experts recommend avoiding crows and poorly ventilated spaces. Spending time in crowded restaurants, bars, and gyms puts you at higher risk for being infected with COVID-19.

Learn more about the Omicron variant from the Centers for Disease Control.

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