Omicron's Incubation Period Is Short: Here's Why That Matters

·3 min read
Omicron's Incubation Period Is Short: Here's Why That Matters

There’s so much public health officials are still learning about the Omicron COVID-19 variant, but one thing is certain: It spreads really quickly. Omicron now causes 99.5% of COVID-19 infections in the U.S.—a staggering number considering that this strain was only detected in the country in early December.

With that, it’s understandable to wonder about Omicron’s incubation period, i.e. the amount of time it takes from when you’re infected to when you start showing symptoms of Omicron. Here’s what you need to know about Omicron’s incubation period, how long you’re contagious with Omicron, and what all of this means for the future of the pandemic.

What is Omicron’s incubation period?

A recent study from the Centers for Disease Control and Prevention (CDC) analyzed data from six people who contracted the Omicron variant of SARS-CoV-2, the virus that causes COVID-19, and found that 73 hours (or three days) was the typical incubation period for patients. However, there was a range: Some developed symptoms as early as 33 hours after being exposed and some became symptomatic after 75 hours.

Those symptoms, according to another CDC report, typically include:

  • Cough

  • Fatigue

  • Congestion

  • Runny nose

The CDC’s researchers point out that Omicron’s incubation period is definitely shorter than the original SARS-CoV-2 (five days or greater) and the Delta variant (four days).

How long are you contagious with Omicron?

In late December, the CDC shortened the recommended time that people should isolate after they’ve been diagnosed with COVID-19. The agency now recommends that you isolate for five days, provided your symptoms are better or you’re asymptomatic, and follow that up with five days of wearing a mask.

The change, the CDC explained at the time, was driven by research that found that most people spread SARS-CoV-2 in the one to two days before they develop symptoms and the two to three days after. So, by that measure, most people are contagious with Omicron for about five days.

Regardless of the length of time you're contagious with Omicron, the variant is “much more contagious than previous variants,” says William Schaffner, M.D., an infectious disease specialist and professor at the Vanderbilt University School of Medicine. The reason, he explains, is that “people exhale much more of the virus and it gives the recipient a larger dose of the virus.”

What does Omicron’s incubation period mean?

Having a shorter incubation period doesn’t mean Omicron is easier to control, Dr. Schaffner says. “Omicron is so contagious,” he says. “It’s very difficult to inhibit its spread on a population basis.”

What the shorter incubation period does mean, though, is that you should consider testing yourself sooner if you had a known exposure to someone with the virus, says Thomas Russo, M.D., professor and chief of infectious disease at the University at Buffalo in New York. The CDC currently recommends that you test yourself “at least” five days after you’ve had close contact with someone who has COVID-19, but Dr. Russo says it should be shorter with Omicron.

“You want to jump on those home tests after about day three of being exposed so you can isolate yourself from others if you’re positive,” he says. If you’re positive, it also means that you may be able to access treatments like monoclonal antibodies or antiviral medications sooner if you’re considered high risk for serious complications from the virus, Dr. Russo says. “Overall, you just have to be ready to be a little more expedient in your actions,” he adds.

Omicron’s shorter incubation period is closer to the flu (which has an incubation period of one to four days), Dr. Russo says. “It is definitely more flu-like in that way,” he says. “At the end of the day, though, testing is what will help you differentiate between what you need to do next.”

This article is accurate as of press time. However, as the COVID-19 pandemic rapidly evolves and the scientific community’s understanding of the novel coronavirus develops, some of the information may have changed since it was last updated. While we aim to keep all of our stories up to date, please visit online resources provided by theCDC, WHO, and your local public health department to stay informed on the latest news. Always talk to your doctor for professional medical advice.


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