A wave of anti-vaccine sentiment has spurred measles outbreaks around the world, and could lead to outbreaks of other preventable illnesses
By Grace Wade
17 July 2025
A 7-year-old receiving an MMR vaccine in Texas, where a major outbreak of measles is occurring
Jan Sonnenmair/Getty Images
A child in the UK died from measles this month. A baby in Canada died from measles in June. Two children in the US have died from measles this year. But it didn’t have to be this way. Measles is a preventable disease – yet we have regressed to a point where we are acting as though it isn’t. And if we don’t act quickly to right the ship, we could see cases of other preventable diseases rise as well.
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The US is in the throes of its largest measles outbreak since it eliminated the virus in 2000. More than 1300 cases have been confirmed so far – the highest number in 33 years. And it isn’t alone. In 2024, Europe reported its highest caseload in more than 25 years, doubling that of the year prior. Last year, there were almost 3000 confirmed cases in England, the highest number on record since it began tracking confirmed cases in 1996. Meanwhile, Canada has had more than 3800 reported measles cases this year – more than the previous 26 years combined.
It is an unprecedented situation. Most of these countries haven’t witnessed measles outbreaks this large since the 1980s and 90s, back when most people only received a single dose of the measles, mumps and rubella (MMR) vaccine. After implementing a two-dose regimen – which is about 97 per cent effective at preventing measles – cases plummeted, and many countries declared measles eliminated around the turn of the century.
That is why this moment is so alarming. Measles is resurging not because we don’t know how to stop it, but because we are no longer trying. “We have never been in a situation where [the spread of measles] was driven by vaccine hesitancy,” says Tina Tan at Northwestern University in Illinois. “This is uncalled for because we have safe and effective vaccines to prevent this from occurring.”
Herd immunity against measles, in which most people in a community are protected, occurs when more than 95 per cent of a population is vaccinated. That threshold was met with the two-dose regimen among US children in kindergarten – which usually starts at age 5 – during the 2019-2020 school year. But four years later, coverage dropped below 93 per cent.