How UV Light Could Zap The Flu Bug

IRA FLATOW: I don’t need to tell you that the flu season has been vicious this year. Some of you might be on your second round battling the infection. This thing comes, and you think you’re feeling better, and it hits you a second time.

And you’ve heard of all the precautions to avoid the flu. Wash your hands. Get a flu shot. Make sure you’re sleeping well.

But what if there was a way to kill the flu before it ever reached your nose, killing the virus floating in the air? Researchers have been working to create a type of lamp that would zap it, kind of like a flu bug zapper. And they have succeeded using a narrow band of ultraviolet light, safe ultraviolet light.

The results were published in the journal Scientific Reports. David Brenner is an author on that study. He is also director of the Center of Radiological Research at Columbia University in New York. And he joins us here in our CUNY studios. Welcome to Science Friday.

DAVID BRENNER: Good to be here.

IRA FLATOW: So there is a specific part of the UV spectrum? Tell us about that.

DAVID BRENNER: Yeah, that’s right. So I think most people know the UV spectrum divides up into UVA and UVB, UVC. And the difference between those is just the different wavelengths. So far UVC, which is where we’re working, is at the far end in terms of wavelengths of the UVC spectrum.

IRA FLATOW: Now, we know that when we put on sunblockers, we know that the UVA and UVB is dangerous. That’s why we’re putting on the sunblocker. But the UVC is not?

DAVID BRENNER: Well, UVC in general doesn’t reach us, because it gets absorbed in the upper atmosphere before it reaches us. But UVC, in general, is a really, really good killer of microbes, bacteria and viruses. And that’s been known for probably 100 years. So it certainly is a good technique for killing influenza virus.

But there is a problem there. And the problem is that UV light in general is a health hazard. It causes skin cancer, causes cataracts in our eyes. So you can use it in places where there are not people, in empty rooms. But what we wanted to do is to use ultraviolet light in a setting where there are people around.

IRA FLATOW: And you found that the UVC is not dangerous for people like the UVA and the UVB is?

DAVID BRENNER: Yeah, that’s right. And there’s a good physics reason for that. Far UVC, it’s actually really, really strongly absorbed by all biological materials. So in biological materials, it simply doesn’t go very far.

For example, if it impinges on our skin, it can’t penetrate through the dead cell layer right at the surface of our skin. And it can’t penetrate through the tear layer on the surface of our eyes. So from our perspective, it’s safe simply because we’re protected from it.

The difference with bacteria and viruses is that they are really, really, really small. They’re far smaller than the outer layer of our skin or eyes. So the far UVC light can penetrate them and get to their DNA and kill them. So it can kill bacteria and viruses, but it can’t damage us. That, at least, is the principle.

IRA FLATOW: I mean, it sounds so obvious. Why hasn’t anybody thought of this before? Not to denigrate what you’re talking about.

DAVID BRENNER: Yeah, there was a little bit of a light bulb going off when we first thought of this, a UV light bulb.

IRA FLATOW: Yeah. Well, what about plants? You know, I’m picturing that what you want to do is make a lamp out of UVC, and then you could hang it in a doctor’s office, or maybe in your own home, and just kill the viruses that may be hanging out. Would that be what the idea is?

DAVID BRENNER: That’s the idea, yeah.

IRA FLATOW: And what if I had plants there? Would it kill my plants, too?

DAVID BRENNER: Well, again, plants also have a surface layer of cells which would protect them. What’s very specific about bacteria and viruses is that they’re really, really, really small, smaller than plant cells, smaller than human cells.

IRA FLATOW: Now let me– I’m glad you brought that up, because on our skins, we have a microbiome of bacteria there, you know?

DAVID BRENNER: Yes, we do.

IRA FLATOW: And they’re beneficial, are they not?

DAVID BRENNER: Yeah, there are certainly good bacteria and bad bacteria in this world. And indeed, there is a whole microbiome not only in the skin, but throughout our bodies. Now, the microbiome inside our bodies is going to be protected from this far UVC light. It simply won’t reach that.

But you’re right. There is a microbiome on the surface of our skin. But actually, life on the surface of anything, on the surface of our skin for a bacterium, for a virus, it’s actually pretty tough.

So if bacteria are sitting on the surface of our skin, well, for example, you wash with antibacterials. You take showers. You go out in sunlight. So all sorts of tough things can happen on the surface of the skin.

So what the bacteria do to protect themselves when they’re there is they cluster into very, very large groups of bacteria. They don’t sit a single bacteria on the surface of our skin. They’re in groups of thousands and kind of held together with sticky, protein-like stuff. So the outside of that big cluster would be potentially amenable to far UVC light. But inside, most of the bacteria are going to be protected.

IRA FLATOW: I got you.

DAVID BRENNER: So basically, I think the far UVC is going to do far less damage to the skin microbiome than simply the things we do normally, washing and going out in sunlight.

IRA FLATOW: This is Science Friday from PRI, Public Radio International. Talking with David Brenner, director for radiological research at Columbia, about this UVC lamp. And of course, you can just put a shirt on. You don’t have to worry about it getting your skin. So how close are we to going to Home Depot and getting a lamp that’s–?

DAVID BRENNER: Not so far. Really, three things have to happen for it to be really, really ready. First of all, we have to definitely demonstrate that it’s effective, that it kills viruses, influenza virus, efficiently.

And that’s what the paper that we published just a week or so ago was about. And the answer is it kills viruses with about the same efficiency as conventional ultraviolet light. And that’s very efficient, indeed.

And one of the big pluses is that it’s going to kill all influenza strains essentially equally well. So we don’t have to have a lamp each year. So we need to show that it’s very good at killing.

We need to show that it’s safe. And so we started off by saying, well, the physics says, in principle it’s safe. But that’s obviously not good enough.

So the last four or five years, we’ve been working pretty intensively on safety studies, both in human skin and mouse skin, and also in eyes. And the conclusion to date, at least, is we have never seen any biological effects, any biological damage, from this far UVC light. And we always do the studies in parallel with a conventional germicidal lamp. And there, we always see biological damage.

IRA FLATOW: One question. A tweet came in from Alex. Flu virus is spread primarily by aerosol. Wouldn’t this UV light have trouble penetrating the droplets?

DAVID BRENNER: Well, actually, that’s what the study that we published last week was. So we actually attached the influenza virus to realistic aerosols and then floated those in front of the UV lamp. And the results were that we were able to kill the viruses very efficiently.

IRA FLATOW: Is this patentable, or is it because it’s UVC, anybody can–

DAVID BRENNER: Well, Columbia has certainly got all sorts of patents in, believe me.

IRA FLATOW: I’ll bet. And you know, it was like almost a “duh” moment, I would imagine. Like, why haven’t we thought of this before?

DAVID BRENNER: Yeah, it was a little bit of that. I guess we had to put together a few different things in our minds to really come up with this.

IRA FLATOW: Yeah, all right. Well, good luck. We’re waiting for this. OK?

DAVID BRENNER: We’re waiting for it, too.

IRA FLATOW: David Brenner, director of the Center for Radiological Research at Columbia University. One last thing before we go. To an aspiring radio rookies out there, hey, you’re an aspiring radio rookie? We’re in the hunt for summer interns.

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Have a great weekend. We’ll see you next week. I’m Ira Flatow in New York.

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