The XEC variant spreads seven times faster than the flu and is associated with five main symptoms: cough, fever, fatigue, sore throat, and loss of taste or smell.

XEC, a new subvariant of Omicron, is rapidly spreading across various countries, particularly in Thailand. Experts warn that this variant is significantly more contagious—up to seven times more than seasonal influenza—and presents with a set of symptoms that are often overlooked. Based on clinical data and expert evaluations, five symptoms have emerged as the most common signs of XEC infection.

1. Cough – The First and Most Noticeable Symptom

Coughing is among the earliest and most prevalent symptoms of XEC infection. Patients typically experience a dry, persistent cough accompanied by a scratchy or irritated throat. According to the Assure Covid-19 Lab in the U.S., over 70% of recent XEC cases reported this symptom.

“XEC-related coughing may persist for several days, even after other major symptoms have subsided,” said Dr. William Schaffner, an infectious disease expert at Vanderbilt University. He advises individuals experiencing prolonged coughing to self-isolate and monitor their respiratory health, as coughing is a highly contagious symptom.

2. Fever and Chills – The Body’s Response to Infection

While not every patient experiences fever, it remains a common symptom among those infected with the XEC variant. The fever usually ranges from mild to moderate (around 37.5–38.5°C), often accompanied by chills and body aches.

The Mayo Clinic notes that fever is a natural immune response triggered by the body to fight viral replication. Dr. Allison Arwady, a public health specialist in Chicago, explains that XEC-related fever generally does not last more than two to three days. However, in individuals with pre-existing health conditions, this symptom may become more severe.

3. Fatigue and Reduced Concentration

A striking characteristic of XEC infection is persistent fatigue, even after other symptoms improve. According to Johns Hopkins Medicine, over 40% of Covid-19 patients may continue to feel exhausted for days or even weeks after recovery.

In the case of the XEC variant, this fatigue is often accompanied by reduced concentration and mild insomnia. “Fatigue is not just an acute symptom; it also indicates the virus’s impact on the central nervous system,” said Dr. Emily Landon, an infectious disease expert at the University of Chicago.

4. Sore Throat from the First Day of Infection

Sore throat is another frequently overlooked symptom, especially during flu season. However, with the XEC variant, many patients report throat pain as one of the very first signs of infection. According to the U.S. CDC, Covid-19-related sore throat tends to appear suddenly and is often described as dry and burning, especially when swallowing.

“Unlike the flu, XEC patients typically do not exhibit nasal congestion or runny nose, making a sore throat a more prominent warning sign,” noted Dr. Jorge Moreno of Yale University.

5. Loss of Taste or Smell Remains a Key Indicator

Although more common with earlier Covid-19 variants, loss of taste or smell is still being reported among many XEC cases. This symptom usually emerges a few days after initial infection and can last for weeks.

Research published in the Journal of the American Medical Association links the loss of smell to inflammation in the nasal and throat areas. While this symptom is now less frequent than during the early pandemic phase, it remains a distinguishing feature that helps differentiate Covid-19 from other respiratory illnesses, according to Dr. Claire Hopkins, an ENT specialist in the UK.