A new vaccine against polio has been found to offer effective protection against the viral disease, which still persists in four countries.

A study published in The Lancet found the monovalent mOPV1 vaccine protected 30% of children in a recent trial in northern India, compared with an 11% protection rate for the old, trivalent vaccine.

It protects against type 1 polio, the most prevalent strain of the virus, which is still endemic in Afghanistan, India, Nigeria and Pakistan.

The new vaccine could give a much-needed boost to the campaign by the World Health Organisation (WHO) to eradicate the disease in all countries.

The disease, which attacks children under 5 and has no cure, can result in paralysis.

Oliver Rosenbauer, of the Global Polio Eradication Initiative at the World Health Organisation (WHO), said: “By using a monovalent polio vaccine you get much better protection faster for fewer doses than with the traditional vaccine.

“Every month in Uttar Pradesh, 250,000 children are born who all need vaccinating. For global success, we need to finish the job quickly.�

Before 1988, when the WHO started a global antipolio campaign, there were more than 350,000 cases worldwide.