Japan is battling its worse measles outbreak in a decade, amid World Health Organisation warnings that global efforts to halt the spread of the disease were failing, in part due to vaccine-skepticism.

More than 170 new cases have been recorded in Japan since the start of the year, according to the public broadcaster NHK, affecting people in 20 of the country’s 47 prefectures.

The WHO cited vaccine skepticism, conflict and poor access to healthcare leading to a 50% increase in measles cases worldwide last year, including developed countries where vaccination coverage has been historically high.