Since the introduction of two polio vaccines 60 years ago, this terrible disease has gone from killing millions (and crippling many more) to near elimination. Yet the gap between being nearly gone and complete abolition of the virus is proving hard to bridge. As long as small reservoirs of such an infectious disease survive, there is a chance it could come roaring back.
Obstacles to elimination include the Western anti-vaccination movement and Islamic fundamentalists opposed to modern medicine, but there are also technical challenges. The vaccines require refrigeration, which isn't easy to come by without electricity networks. The invention of a vaccine that is stable at room temperature could be a game-changer.
"Stabilization is not rocket science, so most academics don't pay much attention to this field," said Woo-Jin Shin of the University of Southern California in a statement. "However, no matter how wonderful a drug or vaccine is, if it isn't stable enough to be transported, it doesn't do anyone much good."
Shin is first author of the paper in mBio announcing a stable polio vaccine, one that is effective after being stored for four weeks at room temperature. There's nothing new to the concept. Freeze-drying measles, typhoid, and meningococcal vaccines have allowed them to be distributed to many remote locations, helping to turn the tide on these infections.
However, previous attempts to freeze-dry and rehydrate polio vaccines damaged their effectiveness and the methods used in other cases didn't work. Shin found a way around that using lab techniques that allow much faster testing of ingredient combinations.
With only 22 cases of polio reported worldwide last year – and hopes high that existing vaccines and portable solar power units will finish the job – widespread application of Shen's work is far from guaranteed.
Even if this turns out to be the case, however, the techniques used here may be applicable to freeze-drying other tricky vaccines or medicines. The work occurred because Shin's supervisor, Professor Jae Jung, got talking to a friend from his student days, Dr Byeong S. Chang, who now runs Integrity Bio, a company working on stabilization.
"He and I decided to do this as we are getting old and we need to directly contribute to human health and life," Jung said. "Creative ideas always start with food and drinks."
Shin worked on the inactivated virus, which is delivered via injection, and formed the original breakthrough against polio. The more easily administered oral vaccine, which uses a weakened form of the virus, largely replaced this for a while. However, the weakened virus causes paralysis in three cases per million doses, leading some countries to switch back to the original.