A joint report by the World Health Organization (WHO) and the UN children’s fund, Unicef, said children under the age of five accounted for more than 40% of the cases reported in Europe and central Asia.

“Measles is back, and it’s a wake-up call,” Hans Henri Kluge, WHO regional director for Europe, said. “Without high vaccination rates, there is no health security.”

The MMR vaccine – which immunises people against measles, mumps and rubella – is 97% effective in fighting off the dangerous virus.

Measles is a highly contagious disease which is spread by coughs and sneezes.

Common symptoms include:

• high fever
• sore, red and watery eyes
• coughing
• sneezing

The measles virus can lead to pneumonia, brain swelling and death.

The WHO/Unicef joint analysis covering 53 countries said there had been 127,350 measles cases reported in the European region in 2024 – the highest since 1997.

A total of 38 deaths had been reported up to 6 March 2025.

Measles cases, they added, had been declining since 1997, but the trend reversed in 2018-19 and cases rose significantly in 2023-24 “following a backsliding in immunisation coverage during the Covid-19 pandemic”.

“Vaccination rates in many countries are yet to return to pre-pandemic levels, increasing the risk of outbreaks,” they warned.

The European region accounted for a third of all measles cases globally in 2024, the joint analysis said. Within that area, Romania had the highest number of cases – 30,692 – followed by Kazakhstan with 28,147.

The WHO/Unicef statement concluded that measles remained “a significant global threat” and urged governments where cases were occurring to take quick action – and those where the virus had not arrived to be prepared to act.

There have been two deaths in the US recently as the disease – which was considered “eliminated” in the US in 2000 – spreads there and across Canada, too.

Falling vaccination rates have been blamed for the recent flare-up.

In Europe, for instance, eight out of 10 people who were diagnosed with measles in the last year were not vaccinated, according to data from the European Centre for Disease Prevention and Control (ECDC).

Estimates from 2023 show that only four countries – Hungary, Malta, Portugal and Slovakia – had met the 95% threshold for vaccination to prevent an outbreak, the ECDC said on Tuesday.

Concern has been expressed in the UK, too, over the spread of the disease, as vaccination rates for two doses have fallen below 90%.

Dr Ben Kasstan-Dabush of the London School of Hygiene and Tropical Medicine warned people against trusting unverified information on their social media.

“We also learnt from the Covid-19 vaccination programme that misinformation can travel rapidly and can influence people’s decisions. It’s important to be mindful that the vaccine information on social media may not be based on scientific evidence,” Dr Kasstan-Dabush said.

A spokesman for President Milei said the decision to exit the WHO was triggered by “deep differences regarding health management especially during the [Covid-19] pandemic”.

The announcement comes just over two weeks after US President Donald Trump signed an executive order to begin the process of withdrawing from the international health body.

The two leaders have expressed admiration for each other, with Milei calling Trump’s re-election the “greatest political comeback in history”, while the US president described his Argentine counterpart as “my favourite president”.

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In an official statement, the Argentine presidential office said that “the WHO was created in 1948 to co-ordinate the response to global health emergencies, but it failed during the biggest challenge: it advocated eternal lockdowns without scientific backing during its battle against the Covid-19 pandemic”.

The statement also argues that “today, evidence suggests that the WHO’s prescriptions don’t work because they are the result of political influence rather than being based on science”.

Argentine media say they expect President Milei to sign an executive order in the coming days which will begin the process of Argentina pulling out from the WHO.

Speaking at a news conference, presidential spokesman Manuel Adorni said that “we Argentines are not going to allow an international body to interfere with our sovereignty, and even less with our health”.

The spokesman argued that an exit from the WHO would provide Argentina with more flexibility to implement policies tailored to its own interests and to administer its funds as it saw fit.

He said membership of the WHO cost Argentina about $10m (£8m) annually.

President Milei, who describes himself as an “anarcho-capitalist”, has been critical of the WHO for some time but the idea of leaving the body appears to have gained traction in the days after Donald Trump signed an executive order setting in motion the US’s exit from the international body.

The two heads of state appear to share mutual admiration for each other.

Javier Milei was the first foreign leader to meet Trump after his election victory on 5 November.

Speaking at a gala at Trump’s Mar-a-Lago resort on the night of their meeting, Milei said that “the winds of freedom [were] blowing much stronger since Trump’s victory”.

Asked by reporters on Wednesday whether President Milei was planning to withdraw from other international bodies or treaties, the presidential spokesman refused to rule out anything.

“The president is very determined when it comes to making Argentina freer, so any link that Argentina has with bodies that go against its freedoms, we’re going to do our utmost to prevent them from interfering in the lives of Argentines.”

Environmental activists in Argentina say they fear that Milei will follow in Trump’s footsteps and also set the wheels in motion to withdraw from the Paris climate agreement – the international treaty which aims to reduce greenhouse gas emissions.

“Oooh, that’s a big one,” the newly inaugurated US president said as he approved the document after arriving back at the White House. It was one of dozens of executive actions he put his signature to on day one in office.

This marks the second time Trump has ordered the US be pulled out of the WHO.

Trump was critical of how the international body handled Covid-19 and began the process of pulling out from the Geneva-based institution during the pandemic. President Joe Biden later reversed that decision.

Carrying out this executive action on day one makes it more likely the US will formally leave the global agency.

“They wanted us back so badly so we’ll see what happens,” Trump said in the Oval Office, referring to the WHO, perhaps hinting the US might return eventually.

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The order said the US was withdrawing “due to the organization’s mishandling of the Covid-19 pandemic that arose out of Wuhan, China, and other global health crises, its failure to adopt urgently needed reforms, and its inability to demonstrate independence from the inappropriate political influence of WHO member states”.

The executive order also said the withdrawal was the result of “unfairly onerous payments” the US made to the WHO, which is part of the United Nations.

When Trump was still in office the first time around, he was critical of the organisation for being too “China-centric” in its tackling of the Covid-19 pandemic.

Trump accused the WHO of being biased towards China in how it issued guidance during the outbreak.

Under the Biden administration the US continued to be the largest funder of the WHO and in 2023 it contributed almost one-fifth of the agency’s budget.

The organisation’s annual budget is $6.8bn (£5.5bn).

WHO Director General Tedros Adhanom Ghebreyesus said they were about to board a plane when the attacks began.

Houthi-run Saba news agency said three people were killed at the airport and 30 injured. It said another three people were killed and 10 wounded in the western Hodeidah province.

The Iran-backed rebel group described the attacks – which also hit power stations and ports – as “barbaric”. Israel’s military said it carried out “intelligence-based strikes on military targets”.

It is unclear whether the fatalities were civilians or Houthi rebels.

In a statement on X, Dr Tedros said he was in Yemen “to negotiate the release of UN staff detainees and to assess the health and humanitarian situation” in the country. He provided no further details about who the UN detainees were.

Referring to the strikes on Sanaa’s airport, he said: “The air traffic control tower, the departure lounge – just a few meters from where we were – and the runway were damaged.

“We will need to wait for the damage to the airport to be repaired before we can leave,” Dr Tedros added.

UN Secretary General António Guterres called the strikes “especially alarming”.

“I regret the recent escalation between Yemen and Israel, and remain deeply concerned about the risk of further escalation in the region.” he wrote on X.

In a statement, the Israel Defense Forces (IDF) said its “fighter jets conducted intelligence-based strikes on military targets belonging to the Houthi terrorist regime on the western coast and inland Yemen”.

It targeted “military infrastructure” at Sanaa’s airport as well as the Hezyaz and Ras Kanatib power stations, and sites in the Al-Hudaydah, Salif and Ras Kanatib ports on the west coast, the IDF said.

In comments shortly after the strikes, Israel’s Prime Minister Benjamin Netanyahu said it would “continue to cut off the terror arm of the Iranian axis of evil until we complete the job”, adding “we are only just starting with [the Houthis]”.

Early on Friday, the IDF reported that one missile fired from Yemen was intercepted before crossing into Israeli territory.

Mohammed Ali al-Houthi, head of the Houthis’ supreme revolutionary committee, called Thursday’s strikes on Yemen “barbaric” and “aggressive”.

He said that “confrontations with American and Israeli arrogance” will continue until the conflict in Gaza stops.

Several people injured by the strikes at the airport in Sanaa told Houthi-run broadcaster Al Masirah that the runway was struck three times before the airport’s control tower was also hit.

One man, who identified himself as Dr Abbas Rajeh, said the police hospital he works in treated 10 patients after the attacks – one had already died, another was in critical condition, and others had minor injuries or broken bones.

Iran described the strikes as a “clear violation of international peace and security”.

Houthi rebels have been attacking Israel since the first months of the Gaza war, which began in October 2023.

A Houthi missile strike injured more than a dozen people in Israel last week.Israel has carried out intermittent strikes against Houthis in retaliation.

Earlier this week, Israel’s defence minister said the country was preparing to “strike hard” at the Houthis, warning it would “decapitate” the group’s leadership.

The Houthis are an armed political and religious group backed by Iran. The group has ruled large parts of western Yemen, including the capital Sanaa, since ousting the internationally recognised government in 2015.