Vaccines are undoubtedly the most successful medical intervention in the history of modern medicine. From smallpox to polio and measles, vaccines have managed to either eradicate or sharply reduce deaths and disability from diseases that once ravaged human communities for thousands of years.
The notable exceptions, however, are viruses like influenza (and AIDS) that mutate so frequently that the human immune system is unable to generate a lasting and effective immune response against new strains. As a result, a vaccine that works perfectly well against this years' flu strain may be useless next year.
Researchers and companies have, however, suspected for some time that it may be possible to create a universal flu vaccine that would target the deep structures of influenza, leading to a robust immune response against multiple strains simultaneously. Ideally, a universal vaccine would eliminate the need (and expense) associated with companies guessing which strains will dominate the flu season in any given year.
Recently, Princeton University researchers confirmed that - at least in theory - a universal flu vaccine could work by providing "herd immunity" to new flu strains:
On a very deep level, these viruses are all related," said Nimalan Arinaminpathy, a postdoctoral research associate in Princeton's Department of Ecology and Evolutionary Biology and the lead author of the study. "The seasonal flu vaccine just works on the surface proteins -- these vaccines would penetrate to the inner part of the virus."
The Princeton team analyzed whether the universal vaccine would protect against a widespread flu, such as the Spanish influenza of 1918, which killed an estimated 50 million people worldwide, or the recent 2009 swine flu.
The researchers determined a universal vaccine could stop such pandemics in their tracks.
"By vaccinating just a part of the population, you reduce the risk of transmission," Arinaminpathy added. "We've never been able to contemplate herd immunity with flu vaccine before."
Of course we won't know if this strategy will really work until we try it en masse.
But if it does work, it will help reduce hospital costs associated with severe flu cases and save thousands (perhaps tens of thousands) of American lives every year.
Despite the fact that vaccination is a two hundred year old technology, researchers are still just beginning to scratch the potential of vaccines to harness the human immune system to fight everything from seasonal flu to metastatic cancer.