A novel polio vaccine that does not require refrigeration could someday be used all over the world to deliver the final blow to the contagious disease that mainly affects children under five years of age, say researchers.

The injectable vaccine, developed by researchers from the University of Southern California (USC) is freeze-dried into a powder and can be kept at room temperature for four weeks, which can then be rehydrated. When tested in mice, the novel vaccine offered full protection against the polio virus, the researchers said.

"Stabilisation is not rocket science so most academics don't pay much attention to this field," said lead author Woo-Jin Shin, from the Keck School of Medicine at USC. "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 added.

The study appears in the journal mBio. By removing moisture through freeze-drying, researchers have created temperature-stable vaccines for measles, typhoid and meningococcal disease. But scientists have not been able to make a polio vaccine that retains potency through freeze-drying and rehydration.

Shin and his colleagues used two lab techniques -- liquid chromatography and high-throughput screening -- that allowed them to analyze a high volume of ingredients and formulations until they found one that worked. They now hope that a foundation or company will take over the project to pay for human studies and bring the injectable vaccine onto the market.

Polio is on the brink of complete eradication, with just 22 reported cases worldwide in 2017. The highly infectious disease, which causes lifelong paralysis and disability mostly in young children, is a fading memory in many places. Yet in countries where vaccination rates are spotty, young children are at risk.

The biggest hitch to complete eradication has been creating a temperature-stable vaccine for use in developing countries where refrigeration may be unavailable. Recent polio cases have been reported in Nigeria, Papua New Guinea, Syria and Pakistan.