Measles infected nearly 10 million people last year and killed 140,000, mostly children, as devastating outbreaks of the viral disease hit every region of the world, the World Health Organisation said on Thursday.
In figures described by its director general as "an outrage", the WHO said most of the 2018 measles deaths were in children under five years old who had not been vaccinated.
"The fact that any child dies from a vaccine-preventable disease like measles is frankly an outrage and a collective failure to protect the world's most vulnerable children," said the WHO's director general Tedros Adhanom Ghebreyesus.
The picture for 2019 is even worse, the WHO said, with provisional data up to November showing a three-fold increase compared with the same period in 2018.
The United States has already reported its highest number of measles cases in 25 years in 2019, while Albania, the Czech Republic, Greece and Great Britain lost their WHO "measles-free" status in 2018 after suffering large outbreaks.
An ongoing outbreak of measles in Samoa has infected more than 4,200 people and killed more than 60.
Globally, measles vaccination rates have stagnated for almost a decade, the WHO said.
It and the UNICEF children's fund say that in 2018, around 86 per cent of children got a first dose of measles vaccine through their country's routine vaccination services, and fewer than 70 per cent got the second dose recommended to fully protect them from measles infection.
In some wealthier nations, vaccination rates have been hit by some parents shunning them for what they say are religious or philosophical reasons or mistrust of authority.
The WHO data showed there were an estimated 9,769,400 cases of measles and 142,300 related deaths globally in 2018. This compares to 7,585,900 cases and 124,000 deaths in 2017.
In 2018, measles hit hardest in Liberia, Democratic Republic of Congo, Madagascar, Somalia and Ukraine, the WHO said, with these five nations accounting for nearly half of global cases.
Robert Linkins, a specialist at the US Centres for Disease Control and Prevention, said: "Without improving measles vaccine coverage we're going to continue to see these needless deaths. We must turn this trend around."
Australian Associated Press