Experts are hoping that polio could be wiped out by the end of the year, despite stubborn pockets of the disease remaining in a handful of countries.

Polio, a highly infectious childhood disease, was once prevalent throughout the world but has been eradicated in most countries thanks to vaccination.

The number of cases of polio has plummeted over the past 30 years, from around 350,000 cases in 1988 to just 22 in 2017, leading experts to predict the disease's imminent demise. But so far their hopes have been dashed.

There are just three countries in the world that have yet to be declared polio free: Pakistan, Afghanistan and Nigeria. According to the Global Polio Eradication Initiative there have been eight cases of polio in Afghanistan and Pakistan so far this year, compared to five at the same point the year before.

In a press briefing to give an update on polio eradication efforts Michel Zaffran, director of polio eradication at the World Health Organization, said he was hopeful that the disease could be eradicated by the end of this year or next.

“We are closer than we have ever been before to wiping out this virus. The next few months will tell us if we may be able to finish the job this year as this is the time when the virus is circulating," he said.