How Long Does Immunity From Omicron Last?

Just like COVID-19 vaccinations, a previous COVID infection provides a high level of immunity against infection. But it’s never 100%, and it wanes over time. Infection also confers high levels of protection against symptomatic COVID-19 illness.

However, the level of protection tends to vary among different COVID variants. Here’s what you should know if you were previously infected with the Omicron variant.

Natural Immunity Can Last for Months

The immunity from infection with Omicron appears to last about as long as the infection with earlier variants, William Moss, MD, executive director of the International Vaccine Access Center at the Johns Hopkins Bloomberg School of Public Health, told Verywell. That means you could be protected for four to six months.

However, that’s just an estimate. Moss says determining Omicron immunity is complex for the following reasons:

• The Omicron wave in the U.S. only started about six months ago, which means researchers have only had a short window to observe immunity trends.
• There are few people who were infected with Omicron and had neither been vaccinated nor infected with an earlier variant. So for most people, the Omicron infection occurred in the context of some existing immunity. That may influence how long you’re protected.

“High levels of antibodies likely last for four to six months after infection with Omicron, as for earlier variants, in most otherwise healthy individuals,” Moss said.

Experts assume that the elderly and those with underlying conditions will have less robust immune protection from an Omicron infection, just as they did to prior variants and to vaccines, Stanley H. Weiss, MD, professor of medicine at the Rutgers New Jersey Medical School, told Verywell.

Interval Between Infection and Reinfection May Be Shorter 

COVID-19 reinfections are generally defined as testing positive more than 90 days after the complete resolution of the primary infection. However, reinfection can still occur earlier than that.

A study from the Centers for Disease Control and Prevention (CDC) identified 10 patients—eight of them younger than 18 years old—who were infected with the Delta variant and reinfected with Omicron. The authors found that the interval between infections ranged from 23 to 87 days, with a median of 54.5 days. Whole-genome sequencing confirmed that the cases did not represent prolonged viral shedding and the patients had two separate infections.

“Omicron and its variants are better able to escape protective immunity from prior vaccination or infection compared with previous variants,” Moss said.

A recent study published in Science confirmed that the Omicron variant has a pronounced ability to evade immunity from prior infection, unlike the Beta or Delta variants.

However, the interval alone does not dictate the risk of reinfection.

“Accurately measuring a change in the interval between infection and reinfection is challenging because there are so many factors that determine the risk of reinfection,” Moss said. “These include the risk of exposure to the virus based on the level of transmission in the community, the nature of the variant being transmitted, and how well it can escape prior immunity.”

Overall, it’s crucial to stay up to date with your COVID-19 vaccinations and continue practicing safety precautions.

“Four doses of an mRNA vaccine has been providing excellent protection against severe disease from Omicron, but incomplete protection from acquiring infection,” Weiss said. “Thus, wearing an excellent-fitting, high-efficacy mask continuously whenever at potential risk remains important for prevention.”

Delaying the Second Booster Shot Is OK

The second booster shot is available for immunocompromised individuals and people ages 50 and above who got their first booster dose at least four months ago. If you are eligible to get your second booster dose but you recently got infected with Omicron, you can choose to get the shot as soon as you’ve fully recovered.

But it’s alright if you don’t want to get the shot right away. For instance, you might want to get the immunity boost closer to an upcoming indoor event or overseas trip.

“Although there are no firm guidelines on the timing of a second booster shot for an individual who was fully vaccinated and boosted and then infected with Omicron, it is best to wait,” Moss said.

Delaying the shot allows eligible individuals to get the second booster when the antibody levels are likely waning. The infection will be providing excellent protection, so the booster dose isn’t necessarily urgent, Weiss said.

“Historical data on other infectious agents had suggested waiting two to four weeks after a viral infection before getting a viral vaccine since the immune system is ramped up and the protection from the vaccine is likely to be less effective,” he added. “So, a short wait is prudent. I’d recommend getting the second booster at about five months after the first booster.”

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.