Senior author Mark Poznansky, director of the Massachusetts General Hospital Vaccine and Immunotherapy Center, said current vaccines are designed to be safe for most patients, but their ability to produce an immune response needs to be strengthened by the presence of adjuvants, which are chemical or biological additives that prime the immune system to respond to the vaccine antigen.
Adjuvants are also responsible for many vaccine-associated adverse events, which is particularly problematic for influenza vaccines. As a result, most flu vaccines recently available in the United States -- including the vaccine against the H1N1 strain responsible for the 2009 pandemic -- contained no adjuvants, which probably limits their effectiveness, Poznansky said.
"We discovered that low-power near-infrared laser light effectively and reproducibly increases vaccine efficacy as well as currently approved adjuvants and is effective for influenza vaccination," Poznansky said in a statement.
"Many of the adjuvants currently in use or in development cause significant side effects -- including inflammation and tissue damage -- and remarkably few adjuvants that would be likely to receive [Food and Drug Administration] approval are available for influenza vaccines. Our results indicate that laser treatment would be a safe and effective alternative."
The study, published in the journal Plos One, found a 1-minute dose of near-infrared laser light significantly improved the effectiveness of intradermal influenza vaccination in a mouse model -- increasing both immune system activity and the animals' survival.