RELATED: If You Have Omicron, This Is When You’ll Begin to Feel Symptoms. According to a Jan. 13 update from the Zoe COVID Study App, the most common symptom of Omicron is a runny nose. “In the early days of the pandemic, it was thought that having a runny nose was not a symptom of COVID-19, and was much more likely to be a sign of a regular cold,” the researchers noted. But now, many experts are saying that Omicron symptoms appear much more like a cold than any other previous version of COVID. “The most reported symptoms of Omicron are really very much like a cold, especially in people who’ve been vaccinated,” Claire Steves, PhD, a scientist from King’s College London involved with Zoe, confirmed in a Jan. 6 video. RELATED: These 4 New COVID Symptoms Could Mean You Have Omicron, Doctors Warn. A headache can arise from a number of sources, but it’s also one of the top signs of an Omicron infection, according to the Zoe COVID Study App. Additional data released from the Washington State Department of Health on Jan. 12 showed that nearly 65 percent of its COVID patients reported having a headache during the recent Omicron surge. “Many respiratory viruses—including COVID—cause headaches,” Amesh A. Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security, told Prevention. William Schaffner, MD, an infectious disease specialist and professor at the Vanderbilt University School of Medicine told the news outlet that an Omicron headache is “more likely to be frontal,” so you’ll probably feel it in your forehead, rather than in the back of your head. Bruce Patterson, MD, a virus expert and founder of cell diagnostic company IncellDX, recently told the Deseret News that the one symptom that has always been “present with COVID” is fatigue, including with Omicron. But if you’ve been infected with this variant, you might notice an all-encompassing exhaustion. When Omicron was first discovered in South Africa, doctors warned of extreme tiredness. “The most predominant clinical complaint is severe fatigue for one or two days,” Angelique Coetzee, a private practitioner and chair of South African Medical Association, told Reuters. RELATED: For more up-to-date information, sign up for our daily newsletter. Sneezing has not often been associated with the coronavirus, so many people with this symptom might think they are just dealing with allergies or a mild cold. But alongside a number of other cold-like symptoms, sneezing is now considered one of the tell-tale signs of Omicron. This is because unlike other variants—including the previously dominant Delta—Omicron has a higher affinity for infecting the upper respiratory system, Emily Landon, MD the chief infectious-disease epidemiologist at University of Chicago Medicine, told The Washington Post.ae0fcc31ae342fd3a1346ebb1f342fcb “It’s more likely to make people sniffle more, sneeze more or be congested,” she said. Another upper respiratory symptom frequently presenting with Omicron is a sore throat. Some doctors have even said it’s the most common problem they are seeing with patients who end up testing positive for COVID. “Predominantly, my biggest complaint is a sore throat or scratchy throat,” Patricia Williams, a family medicine provider with Novant Health, told North Carolina CBS-affiliate WFMY News 2. And some say this Omicron symptom is even more common in one particular group: the vaccinated. “Especially in people who we’re seeing these more mild breakthrough infections, we are definitely seeing sore throat be a predictor in that group,” Allison Arwady, MD, the commissioner for the Chicago Department of Public Health, said in a Facebook Live, per NBC 5 Chicago. RELATED: This Strange Symptom at Night Could Mean You Have Omicron, Doctors Warn.