NEW YORK, Aug 6: A new COVID variant, known as XFG or “Stratus,” is rapidly increasing in prevalence in the United States, becoming the third most common strain this summer. Originally identified in Southeast Asia in January, XFG represented nearly 0% of U.S. cases until May but rose to about 14% by late June, according to the Centers for Disease Control and Prevention (CDC).

The World Health Organization (WHO) has placed XFG on its watchlist but assessed its overall public health risk as “low” globally in a report released in late June. The WHO also noted that current COVID-19 vaccines are expected to remain effective against this variant, preventing symptomatic and severe illness.

What is the XFG variant?

XFG is a recombinant variant, combining elements of the F.7 and LP.8.1.2 variants—the latter being the second most common strain in the U.S. Scientists believe its mutations might help it evade immune defenses, but its mode of binding suggests it is less contagious than other dominant variants. Subhash Verma, a microbiology and immunology professor at the University of Nevada, Reno, told USA TODAY that there is no clear evidence XFG causes more severe illness or different symptoms compared to earlier Omicron variants. He emphasized that there are currently no urgent public health concerns linked to XFG.

How widespread is XFG?

Although spreading globally, XFG has not yet become the leading cause of COVID infections in the U.S. Due to reduced state reporting, the CDC now tracks cases over longer periods. For the two weeks ending June 21, XFG accounted for 14% of U.S. COVID cases, trailing behind NB.1.8.1 (43%) and LP.8.1 (31%).

XFG’s presence in the U.S. grew steadily over recent months: from nearly 0% in March, to 2% in April, 6% in late May, 11% in early June, and 14% by late June. The WHO also reported an increase worldwide, with XFG making up 7.4% of positive tests in early May and rising to 22.7% by the end of June across 38 countries.

What symptoms does XFG cause?

There is no evidence that XFG causes symptoms different from other COVID variants. However, anecdotal reports on social media and in the news have linked the strain with hoarseness. According to the CDC, common COVID symptoms include:

The CDC advises seeking medical attention if you experience:

This information underscores the importance of vigilance as COVID variants continue to evolve and spread.