The Omicron variant is now the dominant COVID-19 strain in the United States, with the subvariant BA.2 accounting for the majority of current cases.
Some studies suggest that Omicron infections last up to about 10 days in the body, which is comparable to the duration of its predecessor, the Delta variant, and slightly shorter than the two week timeframe of the original strain of COVID-19. Whether this slight reduction is due to characteristics in the variant itself, or a higher vaccination rate, is unclear.
“It’s becoming more and more difficult to compare new variants to old variants, because we’re getting so much more immunity in the population,” Andrew Pekosz, PhD, a virologist and researcher at Johns Hopkins Bloomberg School of Public Health, told Verywell. “All those things are making things very, very sort of muddled in terms of trying to make simple statements about what’s happening.”
Despite unknowns, Pekosz said it appears reasonable to assume that once a person’s Omicron symptoms go away, so has their infection.
“It certainly seems like when symptoms go away, infectious virus disappears. And that means you’re probably incredibly unlikely to transmit the virus to anyone else,” Pekosz said. “Particularly if you’re vaccinated, as soon as symptoms go away, you’re pretty much not going to be transmitting the virus to anybody.”
Data Suggests Omicron Infections Last 10 Days After Symptom Onset
There is limited data on how long Omicron infections last in comparison to other variants. But a few existing studies suggest people are unlikely to remain infectious after 10 days.
A small January study on patients hospitalized with Omicron in Japan found that people were unlikely to shed the virus after 10 days of their diagnosis or symptom onset.1
The Japanese study showed people were most infectious with Omicron three to six days after symptom onset. However, it’s important to note that they can be contagious before that, and that not everyone will develop symptoms.
Another study on Delta and Omicron infections in the NBA found that on average, Omicron infections lasted for about 10 days, while Delta infections lasted for about 11 days.2 Whether or not the difference in timeframe could be attributed to characteristics of the variants themselves, or to factors like vaccinations and natural immunity was unclear, according to the researchers.
Vaccination Status Might Not Impact Recovery Time
A recent preprint study by researchers at Johns Hopkins analyzed differences between boosted, vaccinated and unboosted, and unvaccinated patients, separating for Delta versus Omicron.3 The researchers found that people who were fully vaccinated and boosted prior to their infection with the Delta variant had lower viral loads than those who were unvaccinated, but that vaccination status did not impact viral load for people infected with the Omicron variant.3
The study also found that the severity of Delta and Omicron hospitalizations were comparable for people admitted to the hospital, but that people with Omicron appeared less likely to be admitted to the hospital to begin with.3
Still, experts say there’s not a big difference between an Omicron infection and a Delta infection.
COVID-19 testing doesn’t show you which variant you have—that data is only for the sake of public health surveillance, and it wouldn’t change your treatment protocol at this time anyway. But you can get a sense of which variant you’re likely infected with by looking at a CDC dashboard. The CDC’s Variant Proportions page reflects which COVID-19 strains are currently circulating in the U.S. and in specific regions of the country, along with their prevalence.
“Studies aren’t showing that Omicron is much different from other variants you can compare it to in terms of how much virus is in your system and for how long it’s in your system,” said Pekosz, who co-authored the Johns Hopkins study.
For people who believe they’ve been infected with Omicron, taking a COVID-19 test after quarantining or after 10 days can help confirm whether or not the virus is still present in the body.
“We should all take advantage of the antigen tests that are out there,” Pekosz said, noting that more at-home rapid tests are available for purchase now than there were this winter. “It’s a great time for everybody to get a few of those kits at home, because if you’re antigen negative, you’re very likely not to be able to spread the virus and that’s a good thing for people to know.”