A polio vaccine that can be stored as a dried powder at room temperature is a new opportunity to help eradicate the disease, researchers at the University of Southern California say.

The vaccines usually require a cool and stable temperature to ensure the medicine remains effective.

Polio has no cure and can lead to irreversible paralysis. It mainly affects children under the age of five, and can only be prevented by giving a child multiple vaccine doses.

It remains endemic in Nigeria, Pakistan and Afghanistan.

Woo-Jin Shin, one of the researchers involed in the study, told the BBC’s Newsday programme that the freeze-dried polio vaccine did not need refrigeration to keep it stable and effective.

"The main purpose of this project was to store the vaccine in an ambient temperature at 37C and one at 40C and we also used commercial polio vaccines as a reference and we compared the efficacy of the vaccine.

"Frozen-dried ones worked very similar to commercial vaccines.

"The main objective was to transfer the vaccine at different areas where there’s no refrigeration and second we think that we could apply this formulation to different kinds of vaccines and we are pretty sure that it will work."

What is polio?

- Polio, or poliomyelitis, mainly affects children aged under five

- It is a highly infectious disease caused by a virus. It invades the nervous system and can cause total paralysis in a matter of hours

- Initial symptoms include fever, fatigue, headache, vomiting, stiffness of the neck and pains in the limbs

- One in 200 infections leads to irreversible paralysis. Among those paralysed, 5% to 10% die when their breathing muscles become immobilised

- Only three countries in the world have never stopped transmission of polio: Pakistan, Afghanistan and Nigeria.