Ever get a flu shot and still get the flu? If so, there's new hope for flu-free winters in the years to come thanks to a new discovery by researchers who found that a drug called DMXAA, originally developed as anti-tumor agent, enhances the ability of flu vaccines to ward off this deadly virus. A new research report appearing in the March 2011 issue of the Journal of Leukocyte Biology suggests that DMXAA could assist flu vaccines by causing the body to produce its own antiviral proteins, called interferons, which interfere with the virus's ability to spread. In addition, DMXAA may be a useful antiviral therapy to treat newly emerging strains of the flu for which a vaccine has not be developed.

"We are hopeful that DMXAA or similar agents can be used ultimately to blunt the impact of yearly influenza outbreaks, and perhaps, for other virus infections as well," said Stefanie Vogel, Ph.D., co-author of the study and Professor of Microbiology and Immunology at the University of Maryland, School of Medicine in Baltimore.

To make this discovery, Vogel and colleagues infected mice with a mouse-adapted influenza strain. When given DMXAA three hours before or after infection and then two days later, the infection was significantly less severe. In addition, they found that DMXAA protected cells from flu strains that are resistant to Tamiflu®, one of the most advanced anti-flu drugs on the market. These discoveries suggest that DMXAA could potentially enhance the efficacy of current flu treatments and vaccines, and perhaps treat other viruses or bacteria. To be sure that DMXAA led to increased production of interferons, the researchers also tested it in mice that lacked a gene needed to produce interferon, and found that these mice received no benefit from DMXAA.

"H1N1 was a wake-up call that the flu remains a very serious disease, regardless of how "common" we may think it is," said John Wherry, Ph.D., Deputy Editor of the Journal of Leukocyte Biology. "Every year this virus mutates, and history has shown us that new, very dangerous strains of this virus will continue to emerge. New drugs like this one that can combat this virus -- especially drugs that are effective against newly emerging strains -- may prove to be lifesaving for millions of people around the world."