Vaccination rates have fallen for years. Now there is an outbreak of measles in Britain.

The five-year-old nervously looked at her older brothers and scanned their faces for signs of distress as the needles were quickly inserted into their upper arms, the plungers of the syringes were pushed in and the measles, mumps and rubella vaccine was administered. Whether it was to her advantage or not, they hardly flinched.

Then it was her turn. The girl, Grandma Nnagbo, looked wide-eyed at the cheerful nurse who moments later declared: “All ready, 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 word from their school about a measles outbreak in the nearby Birmingham area.

“That is what we have to do, and it is important to do,” Mr 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, are starting to appear in clusters as the number of children receiving the combined measles, mumps and rubella vaccine has declined worldwide. The trend worsened after the coronavirus pandemic due to a lack of access and hesitancy among some groups. The measles virus can cause serious illness and, in the most extreme cases, death.

The number of measles cases increased across Europe more than fortyfold by 2023 compared to a year earlier — from less than 1,000 to more than 40,000 – according to the World Health Organization. And while much of that increase was concentrated in lower-income countries such as KazakhstanMore affluent countries, where higher vaccination rates have long made measles cases rare, are also experiencing worrying outbreaks.

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

Vaccination rates have fallen to precarious levels in some communities, especially those experiencing the highest levels of deprivation. That was less the result of a rising anti-vaccine movement, experts said, than a lack of resources, lack of awareness and some culturally driven hesitancy.

The percentage of children who have been vaccinated through the country routine vaccination program has fallen over the past decade in all diseases, including whooping cough, measles, mumps and rubella, polio, meningitis and diphtheria.

England no longer has the vaccination rate recommended by the World Health Organization, which advises that more than 95 percent of people should have had two doses of a measles vaccine containing weakened amounts of the virus to prevent outbreaks.

England had 84.5 percent measles vaccine coverage at the end of 2023, but in some areas this was much lower. London had a coverage ratio of 73.1 percent overall, even lower than the West Midlands, where coverage stood at 83.6 percent at the end of last year.

Jenny Harries, the health safety agency’s chief executive, said in a statement that lower vaccination rates were linked to inequality.

“While most of the country is protected, in some areas there are still large numbers of children who are still unprotected from preventable diseases,” she said. “Unless uptake improves, we will see the diseases that these vaccines protect against reemerge and cause more severe illness.”

Carol Dezateux, professor of child epidemiology at Queen Mary University of London, said the current measles outbreak was “completely predictable” as immunizations had already fallen to alarmingly low levels before the pandemic. The causes were complex, she said, but lockdowns and concerns about exposure to the coronavirus only exacerbated the problem.

Child vaccination rates in England have fallen steadily over the past decade, partly due to vaccine hesitancy, but also due to a lack of resources and logistical problems in the most deprived areas. It’s not just about the MMR vaccine, said Dr. Dezateux, because there is evidence of rising inequality between rich and poor children in Britain across all five major childhood vaccinations.

“We’re not able to think about how we can move the dial on this point,” in a more coordinated way, said Dr. Dezateux, adding: “Maybe you would like to climb a high mountain, but if you have no prospect of even going to the first base camp, you’re never going to try, you know?

The coverage gap is difficult to close in some areas, Dr Dezateux said, because so much pressure has been put on the country’s National Health Service GPs, who are already under severe strain.

Still, the cost of prevention in the form of vaccines is about 4 percent of the cost of an outbreak, she said, demonstrating the need for a coherent and coordinated plan to work toward better vaccine uptake.

“We know that where resources are brought in, people can do more. It’s not rocket science,” said Dr. Dezateux.

Dr. Milena Marszalek, a research fellow at Queen Mary and a GP in north-east London in an area with one of the worst vaccination rates in the country, said it was a logistical battle to combat falling vaccination coverage.

“There is a real problem with the lack of capacity and the lack of appointments,” she said. “We don’t have the resources necessary to get the children vaccinated.”

Still, some things were working, she said, citing pop-up clinics and reaching out to local imams to relay information about the vaccine’s safety to the area’s large South Asian Muslim community.

Local Haredi Jewish families told her that flexible hours at clinics and walk-in appointments also removed a barrier.

Yet it is often only after a major outbreak that the issue of vaccination takes on greater urgency. Nicole Miles, the chief nurse at Vaccination UK, a group that delivers vaccines for children on behalf of the UK’s National Health Service, and who ran the Wolverhampton clinic, said an accessible, sensitive and tailored approach was important.

“What people don’t realize is how sick it makes you,” Ms. Miles said of the measles virus. “There’s this idea that ‘it’s just measles’ because we haven’t seen cases of measles like we are seeing in years. So people don’t realize how dangerous it can be because it just hasn’t been here yet.”

Ms Miles, 34, and two other nurses who worked on distributing the vaccines, discussed how vaccine hesitancy among their patients was actually quite rare.

“There will always be groups of people who don’t want to be vaccinated,” Ms Miles said. ‘And there’s really nothing we can do about that, right? But we need to vaccinate the people who want to be vaccinated and who have been missed in some way.”

At the Wolverhampton clinic, many of the families who came in said they were not opposed to it but for some reason had not received vaccinations. Like Mr Nnago, many had heard about the vaccination push in schools.

The Okusanya family, originally from Nigeria, have lived in Wolverhampton for two years. Oluwafunmilayo Okusanya, 42, said none of her three children had received the MMR vaccine in their home country, so when she heard about the measles outbreak locally, she knew it was important to get them.

“When the opportunity came up, I thought it was a good thing that they got it,” she said. “It has become very useful. Even though some may not see the need to come out for it, we just have to protect the children.”