Arizona Public Radio | Your Source for NPR News
Play Live Radio
Next Up:
Available On Air Stations
Science and Innovations

Arizona Study: Coronavirus Infection Relieves Pain In Rodents

Kris Hanning

Scientists at the University of Arizona say the virus that causes COVID-19 may have a surprising ability to relieve pain. Laboratory experiments with rodents show when the virus enters the body by binding to a gateway protein called neuropilin, it blocks the first step in the pathway that causes pain. That might explain why so many people diagnosed with COVID-19 don’t feel any symptoms. KNAU’s Melissa Sevigny spoke with Dr. Rajesh Khanna about his findings, published last week in the journal PAIN.

So in simple terms, how is that possible? How is it that a disease can actually make you feel less pain?

Perplexing results, right? The disease itself is fooling you, or the virus is fooling you, into thinking you have no pain, which is advantageous in the case of this virus, because it allows it to spread a lot more. So its unrelenting spread is something that was concerning us. We hypothesized that one of the reasons it was doing that was simply that the virus was endowing you, at least in the pre-symptomatic or asymptotic state, with this feeling of no pain. 

So on one hand this sounds kind of nice, that maybe this disease isn’t very painful for some people, but it sounds like it could also be a problem. Why is that?

It’s a big problem because in the early stages, in the pre- or asymptomatic stages, what this virus is basically being very sneaky. It’s fooling you into thinking that you’re fine, which then results in massive spread…. In fact it’s estimated that 10 to 20 percent of the people who have COVID are accounting for 60 to 80 percent of the actual cases. So that’s a very big concern.

Now we know that COVID 19 can cause damage to your body, there were recent studies for example about it causing damage to the heart. This is still going on even if you might not be feeling in pain?

Oh, absolutely… I’ve been inundated with a lot of emails from across the globe that have been giving me anecdotal evidence. A lot of people that writing to me are suffering from some form of chronic pain, be it from injury, car accident, or from disease, or chemically induced. Amazingly, all of them have one story to tell: which is they have this pain for a long time, they’re on drugs or opioids, excruciating pain, it’s horrible. And guess what? They happen to contract COVID and all of the sudden their pain is gone… There has to be an intimate connection here between pain and COVID that we haven’t fully resolved. 

So what are the next steps in this research?

Really, the virus has taught us two things: first to really recognize the potential for its great spread by understanding some of the key things, some of the unusual things it may be doing…. The second thing the virus has taught us, is basically it’s unveiled a new protein, nueropilin 1, which until now had never been investigated in the context of pain. It’s given us this new target we can now go after in terms of designing therapeutics for developing drugs for pain.

Do you have plans at this stage to extend this beyond the animal model into humans?

Absolutely. That’s always the intent. But in this case it’s a little bit tricky. Very tricky, actually. How would one test the idea that it causes pain relief? People who are asymptomatic or pre-symptomatic are not really going to physicians. What we could do is get blood samples or serum samples from people who had COVID but have recovered to see what’s changing in them… is there something there we could pinpoint that goes back again to our pathway?

Rajesh Khanna, thank you so much for speaking with me.

Thank you so much.

Watch a video explaining how the virus can relieve pain, from the University of Arizona Health Sciences:


Melissa joined KNAU's team in 2015 to report on science, health, and the environment. Her work has appeared nationally on NPR and been featured on Science Friday. She grew up in Tucson, Arizona, where she fell in love with the ecology and geology of the Sonoran desert.
Related Content