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(NEXSTAR) — Wondering if you have a cold or the highly transmissible omicron variant of the coronavirus?

Well, based on the top five symptoms according to the Zoe Covid Study, it might be hard to tell.

The British symptom study utilized data uploaded to an app by residents of London, where omicron is spreading rapidly and is expected to be the dominant variant by Christmas, according to Professor Tim Spector, the study’s lead scientist.

Researchers looked at symptoms reported between Oct. 3 and 10, when the delta variant was dominant, and compared those to the most recent period, Dec. 3-10, when omicron was spreading rapidly.

The top five symptoms reported in December were:

  1. Runny nose
  2. Headache
  3. Fatigue (either mild or severe)
  4. Sneezing
  5. Sore throat

“As our latest data shows, omicron symptoms are predominantly cold symptoms — runny nose, headache, sore throat, and sneezing — so people should stay at home as it might well be COVID,” Spector said. “We are also seeing two to three times as many mild infections in people with boosters in omicron areas as we do in delta variant areas, but they are still very protective and a vital weapon.”

The cold-like symptoms reported three days after a positive test were not vastly different from those of the delta variant, researchers found. The early data suggests that omicron arrives with symptoms distinct from earlier variants, which caused more flu-like, initial symptoms.

Experts warn that it’s too early to assume that omicron, which is highly transmissible and heavily mutated, will end up being a mild variant.

“In the new year, cases could hit a peak higher than anything we’ve ever seen before,” Spector said of the variant’s spread in the UK.

Omicron spreading in the U.S.

President Joe Biden’s administration has resisted tightening any restrictions, but also sketched out dire scenarios for the unvaccinated in a plea for hesitant Americans to get the shot.

“For the unvaccinated, you’re looking at a winter of severe illness and death, for yourselves, your families, and the hospitals you may soon overwhelm,” White House coronavirus response coordinator Jeff Zients said.

On Tuesday, President Biden held a press conference, pledging 500 million free at-home COVID tests as Christmas nears.

Meanwhile, there have been cancellations across the country. The Radio City Rockettes called off four performances because of breakthrough COVID-19 cases in the production. Hours later, the Rockettes canceled the rest of this season’s performances “due to increasing challenges from the pandemic.” The popular holiday program generally has four shows per day in December at Radio City Music Hall in Manhattan.

Dr. Stanley Weiss, a Rutgers University epidemiology professor, said officials need to react faster, citing a willingness to redefine fully vaccinated to include booster shots, for example.

“Everyone wants us to be through with this pandemic, but in order to get us through it, we can’t ignore the realities of what’s going on and what is needed,” Weiss said.

The Associated Press contributed to this report.