We all know that vaccines need refrigeration to preserve their structure and immunogenicity. But in the case of children living in remote hinterland across the globe that get less or no electricity, this becomes a daunting task.

Half of the vaccines sent to developing countries are lost as they deteriorate during transportation.

The answer to preserve vaccines for such places lie in coating viruses or viral bits with silica in a hot-spring environment, says a new study published in The New York Times.

Scientists at Portland State University prevented several viruses from drying out by coating them with silica, used primarily in the production of glass for windows, just as they are coated in hot springs. 

Once the silica coats were rinsed off, some of the viruses were able to infect cells again, said the NYT report.

"It's hard to put a fridge on the back of a donkey so we require such vaccines," Kenneth M. Stedman, lead author of the study, was quoted as saying.

Stedman and his team coated four types of virus with silica, stored them, then washed off the silica and tried to infect cells. 

One heavily studied virus, phage T4, which infects the cells of E. coli bacteria, retained 90 percent of its infectivity while the virus used in smallpox vaccines also did well.

The team is now on the job to test the technique on flu virus and rotavirus, and later, polio. Next on the list is testing them in animals instead of cells.

Every year, nearly 22 million people in the world do not receive the necessary vaccines they need. One of the reasons is that vaccines must be kept at exactly the right temperature, between 2-8 degrees Celsius, or else their quality and effectiveness deteriorate.The study appeared in Journal of Virology.