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 wakeup 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 Organization 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 ten nations accounting for 75% 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 2,269. In the United States, there was a 559 per cent year-on-year increase in cases from 120 to 791.
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.
Yemen figured on UNICEF's top 10 list of countries showing the largest increases last year in measles cases with a 316% hike, from 2,101 cases in 2017 to 8,742 cases in 2018.
Other countries with huge jumps last year compared to 2017 are Venezuela (4,916 more cases, up 676%), Serbia (4,355 more cases, up 620%), Madagascar (4,307 more cases, up 5,127%), Sudan (3,496 more cases, up 526%) and Thailand (2,758 more cases, up 136%).
A few countries saw declines in the number of confirmed cases of measles.
In Romania, reported cases dropped 89% from 8,673 to 943, and in Indonesia the number declined by 65% from 11,389 to 3,995. Nigeria, Pakistan, Italy and China also saw drops of 35 to 55%.