The CDC is reporting a seasonal surge in COVID-19 cases in a majority of states, with Texas listed as "growing or likely to grow".
Much of that activity stems from the NB.1.8.1 variant, also known as "NIMBUS".
Dr. Trish Perl, a Professor in the Department of Internal Medicine at UT Southwestern Medical Center, specializing in general infectious diseases, talked with KERA's Sam Baker about what you should know about "NIMBUS".
Dr. Perl: This variant binds well to the ACE2 inhibitor, which is the receptor that the SARS-CoV-T strains bind to, which makes it more infectious. And in the lab studies, it's about two-and-a-half times more infectious than the previous strains. So, it's spreading very rapidly.
Baker: Does it cause more severe illness than past variants?
Thus far, the data does not suggest that at all. The data suggests a respiratory-like illness. It has some very special symptoms, if you will, but any of these can cause serious disease in the right host. So, in high-risk people, it could certainly cause serious disease.
Speaking of the symptoms, the one that's getting a lot of attention is this so-called "razor blade" sore throat. I know sore throat has been a symptom of COVID before, but what stands out about this one?
The other symptoms - the cough, the fever, the chills, all of that - we've seen in the past, but it's really that it's got a much more prominent sore throat.
The other thing that we're hearing and seeing a little bit is that there are more gastrointestinal symptoms. Some people may present with nausea, vomiting, diarrhea, or even the flip side with bloating and constipation.
So, it does have a little bit of a different, what we will say, constellation of symptoms.
There's still another variant out there, I believe it's called Stratus?
So, also a descendant of Omicron, this particular variant was first identified in Canada. It's not as much of a player in the U.S., I think about 30% and similar symptoms. It's not as infectious as the Nimbus strain, but it is a little better in evading the immune system.
Do the current COVID vaccines stand up to Nimbus?
It's a little early to know exactly how effective these vaccines will be, but based on laboratory data, maybe not 100% effective. They may actually just prevent severe disease, which is really what some of the other vaccines have done. They haven't necessarily impeded you from getting the disease, but they've prevented the really serious consequences.
That said, beyond or apart from vaccines, how do we protect ourselves against Nimbus?
This is like all respiratory viruses, right? You sort of need to be very vigilant, especially in crowded situations. That's where a lot of the transmission occurs, in homes, et cetera.
Washing your hands is very important. Making sure that you get adequate sleep, that you're eating well, et cetera. And then finally, if you're going into these high-risk situations where there are a lot of individuals who can consider wearing masks.
The CDC lists Texas among the states where COVID cases are growing. Why Texas ahead of other states?
I don't know that there is data behind it, but I can tell you that there are interesting associations.
For example, Texas starts seeing influenza before the rest of the country. It may be something about our geography also.
The other thing that's interesting is that right now there's a little bit more COVID activity down in Houston than there is in North Texas.
So, is it warmer weather? Is it that people are inside more as we've really gotten into the heat? Is it something about the humidity? All of which are factors that have been thought to contribute to some other transmission.
I don't know, but that could be part of what is contributing to this.
RESOURCES:
Why do COVID-19 cases rise every summer? CDC reports surge in Texas, 9 other states
Current Epidemic Trends (Based on Rt) for States
Why COVID Spikes in the Summer, and How to Stay Safe
What to know about the Nimbus COVID-19 variant
The Rise of the Nimbus COVID Variant: What Parents Need to Know This Summer (2025)
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