Measles — once on the verge of being defeated globally — is surging again, thanks to vaccine skepticism.

A high-profile outbreak in Texas has attracted the most attention, but the problem is worldwide. Canada has had more cases than the entire US this year, and could soon lose its status of having eliminated the virus, while the European Union saw an almost tenfold annual increase in reported cases to more than 35,000 in 2024.

The change is driven by falling vaccination rates: Measles is highly contagious and 95% vaccine coverage is needed to break transmission, but many countries have uptake of 80% or less, with the lowest rates among ethnic minorities. In London, just 73% of five-year-olds are vaccinated.