Researchers have come up with a new addition to the typical flu shot procedure: a brief blast of laser light to the skin.
Scientists at the Vaccine and Immunotherapy Center at Massachusetts General Hospital (MGH) have found that pre-treating the site of intradermal vaccinations (vaccines delivered into the skin rather than the muscles beneath) with a specific wavelength of light can dramatically improve the effectiveness of flu shots.
After more than a year of testing a series of laser light pretreatments and vaccines on mice, as well as different strengths of laser light on humans, researchers found that a low-power near-infrared laser was very good at increasing the vaccine's potency.
The flu caused nearly 400,000 hospitalizations in the U.S. last year, according to the Centers for Disease Control and Prevention (CDC).
Though influenza is very contagious, there are steps you can take to prevent a mid-season bout of the flu. The easiest is getting a flu shot. The CDC reported that last year flu shots prevented nearly 80,000 hospitalizations and more than 6.5 million cases of the flu in the U.S.
Shining a Light on the Flu Virus
Some vaccines can be made more effective by adding adjuvants. Adjuvants are additions to a vaccine that amplify the body's natural immune response, causing it to release more antibodies to fight the flu virus.
Some chemical adjuvants can produce negative side effects, including soreness or tenderness at the site of the vaccine injection.
Laser light, however, is different.
“The key thing is that it’s transient. Chemical adjuvants hang around in your skin and cause pain,” says study author Mark Poznansky, M.D., Ph.D., director of the Vaccine and Immunotherapy Center. “If you can mitigate those side effects of a chemical adjuvant, that’s a big deal.”
Poznansky and his team, including lead scientist Dr. Satoshi Kashiwagi, M.D., Ph.D., have found that a laser produces ample immune responses within 24-hours, which is a much shorter time than the residual effects of chemical or biological adjuvants last. Ideally, Poznansky says, a hand-held laser device could be used by anyone administering a flu shot.
The researchers got the idea for a laser light adjuvant from Russian scientists after another investigator at the Vaccine and Immunotherapy Center saw Russian physicians using lasers to treat advanced kidney cancer.
“Technologies were coming out of Russia, and they needed to be validated. That’s really how we got into lasers in the first place,” Poznansky says.
Choosing a Laser Light
Researchers identified the strongest near-infrared laser that did not cause tissue damage and worked well on people of all skin tones.
They tested the laser on human volunteers who reported no discomfort after two minutes of exposure. They employed the same type of laser used for tattoo and hair removal, but at much lower power.
Seven-week old mice were given a short pre-treatment with the laser light, followed by a flu shot. Researchers found that a one-minute exposure to near-infrared light greatly improved the vaccine's performance.
Ideally, researchers want to get the 60-second exposure time down to 30, or even 15 seconds, Poznansky says.
Moving forward, researchers hope to explore laser-light treatments for other illnesses, such as hepatitis and cancer, Poznansky says. “The key thing we’re going to look at is how to accelerate vaccines and immunotherapy,” he says.