Just 10 countries were responsible for three-quarters of a global surge in measles cases last year, the UN children's agency has said, including one of the world's richest nations, France.
Ninety-eight countries reported more cases of measles in 2018 compared with 2017, and the world body warned that conflict, complacency and the growing anti-vaccine movement threatened to undo decades of work to tame the disease.
"This is a wake-up call. We have a safe, effective and inexpensive vaccine against a highly contagious disease - a vaccine that saved almost a million lives every year over the last two decades," said Henrietta Fore, executive director of UNICEF.
"These cases haven't happened overnight. Just as the serious outbreaks we are seeing today took hold in 2018, lack of action today will have disastrous consequences for children tomorrow."
Measles is more contagious than tuberculosis or Ebola, yet it is eminently preventable with a vaccine that costs pennies.
But the World Health Organisation last year said cases worldwide had soared nearly 50 per cent in 2018, killing around 136,000 people.
Ukraine, the Philippines and Brazil saw the largest year-on-year increases. In Ukraine alone there were 35,120 cases - nearly 30,000 more than in 2017.
Brazil saw 10,262 cases in 2018 after having none at all the year before, while the Philippines reported 15,599 cases last year compared to 2,407 in 2017.
Taken together, the 10 nations accounting for 75 per cent of the increase from 2017 to 2018 account for only a tenth of the global population.
The countries with the highest rate of measles last year were Ukraine (822 cases per million people), Serbia (618), Albania (481), Liberia (412), Georgia (398), Yemen 328), Montenegro (323) and Greece (227).
While most of the countries that experienced large spikes in cases are beset by unrest or conflict, France saw its caseload jump by 2269.
In the United States, there was a 559 per cent year-on-year increase in cases from 120 to 791.
Misinformation and mistrust
The resurgence of the disease in some countries has been linked to medically baseless claims linking the measles vaccine to autism, which have been spread in part on social media by members of the so-called "anti-vax" movement.
The WHO last month listed "vaccine hesitancy" among the top 10 most pressing global health threats for 2019.
"Almost all of these cases are preventable and yet children are getting infected even in places where there is simply no excuse," Fore said.
"Measles may be the disease, but all too often the real infection is misinformation, mistrust and complacency."
In war-torn Yemen, where health services in many regions have collapsed, UNICEF and the World Health Organization joined with local authorities last month in a campaign to vaccinate some 13 children aged six months to 15 for measles and rubella.
UN officials estimated that 92 per cent of the targeted children were jabbed during the one-week push, which ended on February 14.
Yemen also figured on UNICEF's "top 10" list of countries showing the largest increases last year in measles cases with a 316 per cent hike, from 2101 cases in 2017 to 8742 cases in 2018.
Other countries with huge jumps last year compared to 2017 are Venezuela (4916 more cases, up 676 per cent), Serbia (4355 more cases, up 620 per cent), Madagascar (4307 more cases, up 5127 per cent), Sudan (3496 more cases, up 526 per cent)and Thailand (2758 more cases, up 136 per cent).
A few countries saw declines in the number of confirmed cases of measles.
In Romania, reported cases dropped 89 per cent from 8673 to 943, and in Indonesia the number declined by 65 per cent from 11,389 to 3995.
Nigeria, Pakistan, Italy and China also saw drops of 35 to 55 per cent.
