There was an “alarming” 30-fold increase in measles cases in Europe last year, the World Health Organization (WHO) says.
Health chiefs are warning that cases are still rising and “urgent measures” are needed to prevent further spread.
More than 30,000 people were infected in 2023, compared to 941 during the whole of 2022.
The WHO believes this is a result of fewer children being vaccinated against the disease during the Covid pandemic.
In the UK, health officials said last week that an outbreak of highly contagious measles in the West Midlands could spread rapidly to other towns and cities with low vaccination rates.
More than 3.4 million children under the age of 16 are unprotected and at risk of becoming ill from the disease, according to NHS England.
Millions of parents and carers are being contacted and urged to make an appointment to ensure their children are fully vaccinated against measles. The measles, mumps and rubella (MMR) vaccine is given in two doses – the first around the age of one and the second when a child is about three years and four months old.
The vaccine is very effective at protecting against measles, but only 85% of children starting primary school in the UK have had both jabs.