A new Covid-19 variant, called XFG or “Stratus,” is making waves in the United States. The strain has quickly overtaken the previous dominant variant, NB.1.8.1 (also called Nimbus), and is spreading just as the US enters the fall respiratory virus season, a time when flu, RSV, and common cold cases usually rise.
Stratus is spreading fast
According to the Centers for Disease Control and Prevention (CDC), overall Covid activity in the US is currently ‘moderate.’ But 19 states, including Nevada, Utah, Connecticut, and Delaware, are seeing ‘high’ or ‘very high’ levels of the virus. Stratus is a hybrid of two Omicron sub-variants and was first detected in Southeast Asia in January before reaching the US this spring. By June, it had been reported in 38 countries, prompting the World Health Organization (WHO) to list it as a ‘variant under monitoring.’
Stratus symptoms to watch out for
Doctors say Stratus often causes hoarseness, scratchy throats, or mild sore throats, symptoms that could easily be mistaken for allergies. Unlike Nimbus, which became infamous for its sharp ‘razor blade throat,’ most Stratus infections have been mild, especially among vaccinated people.
Still, the variant carries mutations that help it partially evade immunity from vaccines or previous infections. Health experts continue to recommend simple precautions: stay home if you’re sick, practice good hygiene, improve indoor ventilation, and keep up with vaccines.
Vaccines still work
The CDC’s Advisory Committee on Immunization Practices (ACIP) recently recommended the updated 2025–2026 Covid vaccines for all Americans aged six months and older. Even though Stratus can bypass some immune defenses, vaccines still provide strong protection against severe disease, hospitalisation, and death.
How to stay safe
Stratus spreads easily, hence it is important to take necessary precautions. Experts recommend following safety measures to stay protected. Getting vaccinated remains important, as vaccines protect against serious illness. If you experience symptoms like a sore throat, cough, or fever, it’s important to get tested and isolated to prevent spreading the virus.
Wearing masks, especially N95 or KN95 and maintaining good ventilation can also reduce risk. Make sure you wash your hands regularly to reduce the risk of infection. Older adults, people with chronic conditions, or those with weaker immunity, are more at risk and should be extra cautious.