What Are The Symptoms Of The "Stratus" COVID-19 Subvariant That's Hitting The USA?

Class is back in session for another year, and that means new stationery, pumpkin spice everything in stores, and – albeit less welcome – the spread of respiratory viruses. 

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Only a few months ago, we introduced you to the Nimbus variant of COVID-19; but, there’s yet another new variant we think you should know about. Sticking with the cloud theme, this one’s called Stratus, or more officially XFG.

As Professor of Infectious Diseases and Microbiology Paul Griffin explained in a piece for The Conversation, Stratus is a recombinant variant. This means it arose when two other variants, LF.7 and LP.8.1.2, shared genetic material. 

According to Gavi, Stratus was first detected in Canada before spreading across the globe. It's thought this variant is a major driver behind the current increase in cases in the USA, but Nimbus is probably still around too.

Wastewater data collected by the US Centers for Disease Control and Prevention for the period August 31 to September 6 (the most recent at time of writing) categorized SARS-CoV-2 activity as "Very High" in 19 states/territories across the country.

What are the Nimbus and Stratus subvariants?

Like Nimbus, and the other recent variants before it, Stratus is a subvariant of the Omicron lineage. In fact, there are now over 1,000 of these sublineages. Nicknames have been proposed by researchers and citizen scientists to help differentiate between some of them. We went through a phase of using characters and creatures from Greek mythology, like Kraken; now, we’ve moved on to meteorological terms.

But whatever you call them, it’s important to remember that all these subvariants are members of the same big, complicated virus clan.

“So far, these sublineages of Omicron have much in common: they are all highly transmissible, replicate in the upper respiratory tract and tend to cause less severe disease compared to previous variants of concern, and they all have mutations that make them escape built-up immunity more easily,” explains the Memorial Sloan Kettering Cancer Center.

“This means that they are similar in their impact on public health, and the response that is needed to deal with them.”

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What are the symptoms of the Stratus variant?

For people infected with the Stratus variant, the symptoms are likely to be broadly the same as we’ve seen with other Omicron subvariants. That means the familiar constellation of cough, congestion, fatigue, headache, and sometimes a fever. Some people have also experienced gastrointestinal symptoms.

However, each time we get one of these new lineages it seems there are one or two symptoms that particularly catch people’s attention. With Nimbus, it was the “razor-blade throat” – an especially painful sore throat. For Stratus, we’re sticking to the same bodily region.

“One of the most noticeable symptoms of the Stratus variant is hoarseness, which includes a scratchy or raspy voice,” GP Dr Kaywaan Khan told the Independent.

There’s no empirical evidence from studies that these symptoms are more common with either of these variants, but this is what people have been reporting when seeing their doctors.

As of August 29, there were three COVID-19 “variants under monitoring”, according to the European Centre for Disease Prevention and Control: Nimbus, Stratus, and LP.8.1. This designation means that the WHO is reviewing the global epidemiology of each variant and tracking their spread around the world. The next level up would be a variant of interest, and then a variant of concern (VOC). Currently, no circulating variants fit the VOC criteria.

As best as scientists can tell, the current COVID-19 vaccines should still be effective against the latest variants, even though they may have some ability to evade prior immunity. Some countries and health authorities are rethinking their approach to COVID vaccination, meaning you may not be able to access a booster this year even if you've had them in the past. 

It's worth remembering that if you're concerned about infection, there are other tools at your disposal: you could still choose to wear a mask, and consider looking into air filtration systems or simply opening windows to let in fresh air.

And if you do get sick, do what you can to stay home and keep your distance from more vulnerable people.

An earlier version of this article was published in July 2025.