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Microneedles May Alleviate Shots' Pain, Help With Global Vaccine Distribution


Is there a way to get the coronavirus vaccine without the pain of a shot? Here's NPR science correspondent Joe Palca.

JOE PALCA, BYLINE: It's that darn needle that's the problem. But if you make the needle small enough, there is no pain. Mark Prausnitz from Georgia Tech University uses something called a microneedle to deliver vaccines. The microneedles are part of a patch he's used to deliver flu vaccines, but a similar patch could be used for a COVID-19 vax as well. Prausnitz says you do feel something when the microneedles are pressed against your skin.

MARK PRAUSNITZ: If someone took some Velcro and pressed that firmly against your skin, there's kind of a roughness. Some people may describe it as a kind of tingling. So there is a sensation, but it's a sensation that people don't find objectionable or painful.

PALCA: Prausnitz says the microneedle patch was an offshoot of the computer chip industry. Chipmakers got really good at making tiny structures out of silicon.

PRAUSNITZ: They got smaller and smaller and eventually got down to the micron scale, which is what we need to make the microneedle patches.

PALCA: Turns out your skin is a pretty good place to deliver a vaccine. It's full of immune cells. Prausnitz says the outermost part of the skin consists of a layer of cells thinner than a sheet of paper.

PRAUSNITZ: So in principle, if you want to get into the body across this barrier layer of the skin, you don't need something that measures millimeters and then centimeters long, like conventional hypodermic needles; you need something actually very short - just tens of microns in length.

PALCA: Those tiny needles are now frequently made out of water-soluble materials. So once they get into your skin, they dissolve, releasing whatever you've packed inside of them - in this case, a vaccine

NADINE ROUPHAEL: The microneedle patch technology, the advantage of it, it's just - it's so easy to use. You can give the vaccine to yourself and it doesn't hurt.

PALCA: Nadine Rouphael is a vaccine developer at Emory University. She's worked with Prausnitz developing the flu vaccine delivered by microneedles.

ROUPHAEL: The other wonderful thing is the fact that the vaccine and the microneedle patch is very stable, no matter what the temperature outside is.

PALCA: That would make getting vaccines to remote places way, way easier. Thanh Nguyen at the University of Connecticut is developing a way to make delivering vaccines easier still. He's made a patch that can deliver multiple vaccine doses spaced days or weeks apart, all with a single application. The trick is to embed the vaccine in needles that dissolve at different rates.

THANH NGUYEN: The patient wouldn't need to remember the schedule of the vaccination. They wouldn't need to receive another patch for repeatedly receiving the vaccines.

PALCA: So with all these promising applications, why are there no vaccines delivered by microneedle patches on the market? Darin Zehrung of the global health organization called PATH in Seattle says the answer is clear.

DARIN ZEHRUNG: What's needed is the commitment by industry to that as a particular product.

PALCA: Notice I just said no microneedle patch for vaccination - you can go on the internet now and buy microneedle patches from cosmetic companies that promise to smooth your skin and remove wrinkles. Zehrung says, for vaccines and other medical applications, there are still questions about just how well the patches will work. Initial studies are encouraging but not definitive. And then there's the question about whether they can be manufactured at scale for a reasonable cost. Zehrung has been banging the drum for microneedle patches for 15 years, largely because he thinks they would provide a better way to distribute vaccines globally.

ZEHRUNG: I am more optimistic than I have been in the past. I think we're getting closer.

PALCA: The world would be the beneficiary if he's right.

Joe Palca, NPR News.


Joe Palca is a science correspondent for NPR. Since joining NPR in 1992, Palca has covered a range of science topics — everything from biomedical research to astronomy. He is currently focused on the eponymous series, "Joe's Big Idea." Stories in the series explore the minds and motivations of scientists and inventors. Palca is also the founder of NPR Scicommers – A science communication collective.