The five-year-old looked nervously at her older brothers, scanning their faces for any sign of distress as needles were swiftly stuck into their upper arms, the syringe plungers pushed in and the measles, mumps and rubella vaccine administered. Whether it was for her benefit or not, they barely flinched.

Then it was her turn. The girl, Oma Nnagbo, looked wide-eyed at the cheerful nurse who a moment later declared, “All done, very brave!”

Michael Nnagbo, 40, had brought his three children to this pop-up vaccine clinic in Wolverhampton in England’s West Midlands after receiving a notice from their school about a measles outbreak in the nearby Birmingham area.

“It’s what we have to do, and it’s important to do,” Nnagbo said. “I just want them to be safe. And it was easy, you could just walk in.”

Cases of measles, a highly contagious but easily preventable disease, have begun to crop up in clusters as the number of children getting the combined measles, mumps and rubella vaccine has declined globally. The trend worsened after the coronavirus pandemic because of a lack of access and hesitancy among some groups. The measles virus can cause serious illness and, in the most extreme cases, death.

Across Europe, measles cases rose more than 40-fold in 2023 compared with a year earlier — from less than 1,000 to more than 40,000 — according to the World Health Organisation. And while much of that increase was concentrated in lower-income nations such as Kazakhstan, more prosperous nations, where higher vaccination rates had long made cases of measles rare, are also experiencing worrying outbreaks.

In Britain, 650 cases of measles were confirmed between October 1 and the end of February, according to the UK Health Security Agency, which declared a national incident in January. The rise in cases was initially driven by an outbreak in the West Midlands, but it has spread elsewhere around the country. Most of the cases in Britain are in children under 10.

Vaccine coverage has waned to precarious rates in some communities, particularly those facing the highest levels of deprivation. That was less the result of a surging anti-vaccine movement, experts said, than a lack of resources, lack of awareness, and some culturally driven hesitancy.

The percentage of children being immunised through the country’s routine vaccination programme has fallen over the past decade across all illnesses, including whooping cough, measles, mumps and rubella, polio, meningitis and diphtheria.

England no longer has the levels of vaccine coverage recommended by the WHO, which advises that more than 95 per cent of people must have had two doses of a measles vaccine that contains weakened amounts of the virus to prevent outbreaks.

England had 84.5 per cent measles vaccine coverage by the end of 2023, but in some areas it was far lower. London had a coverage rate of 73.1 per cent overall, even lower than the West Midlands, where the coverage was 83.6 per cent at the end of last year.

Jenny Harries, the chief executive of the health security agency, said in a statement that the lower vaccine rates were linked to inequality.

“While the majority of the country is protected, there are still high numbers of children in some areas that continue to be unprotected from preventable diseases,” she said. “Unless uptake improves we will start to see the diseases that these vaccines protect against re-emerging and causing more serious illness.”

Carol Dezateux, a professor of pediatric epidemiology at Queen Mary University of London, said the current measles outbreak was “entirely predictable”, as immunisations had fallen to alarmingly low levels even before the pandemic. The causes were complex, she said, but the lockdowns and worries about exposure to the coronavirus made the problem worse.

New York Times News Service