There has been a dramatic rise in measles cases reported in Europe, with the disease returning in four countries where it had been eradicated, the World Health Organisation said on Thursday.
The highly infectious and potentially fatal disease is no longer considered eradicated in the UK, Albania, Greece and the Czech Republic, based on WHO data from 2018.
"Re-establishment of measles transmission is concerning," said Gunter Pfaff, head of the WHO's commission keeping track of measles and rubella in Europe.
"If high immunisation coverage is not achieved and sustained in every community, children and adults will suffer unnecessarily and some will die."
The number of measles cases reported in 48 European countries in the first six months of 2019 is more than double that in the same period last year.
The WHO said that between January and June 2019, there were 89,994 cases of measles, compared with 44,175 cases from January to June 2018.
A country is considered free from measles when there is no endemic transmission for 12 months.
In the UK, 953 cases of measles were reported in 2018 and 489 for the first six months of 2019.
Those figures for Greece were 2,193 and 28 cases, the Czech Republic 217 and 569, and Albania 1,466 and 475.
Measles can be prevented through two doses of the vaccine against measles, mumps and rubella, which is available for free in many European countries, including the UK, for all young children.
"Each of these countries are examples that have extremely high national vaccination coverage," said Kate O'Brien, director of the WHO's immunisation department.
"So these are not examples of countries that have particularly weak systems. This is the alarm bell that is ringing around the world.
"Being able to achieve high national coverage is not enough, it has to be achieved in every community, and every family for every child."
Measles is already considered endemic in France and in Germany, where vaccination against the disease will be mandatory from 2020.
Worldwide, almost 365,000 cases have been reported this year, close to three times as many as the first half of 2018, the WHO said.
The Democratic of Congo, Ukraine and Madagascar have had the largest outbreak of measles.
The latest data available for the UAE showed the country was bucking the global trend, with nine confirmed cases of measles reported in the first three months of 2019 compared with more than 60 in the same period in 2018.
The US eradicated measles in 2000 but health experts have warned the country could lose its measles-free status as soon as October this year, after reporting the highest number of cases in 25 years.
Why the rise?
Measles had been steadily decreasing until 2016 in countries with advanced healthcare systems when a global resurgence began, the WHO said.
The reasons for the rise vary from country to country. Lack of access to healthcare and vaccination programmes is one factor, while misinformation about measles and how to prevent it is another.
The “anti-vax” movement, which has falsely linked the MMR vaccine to autism in children, has gained traction online, influencing parents’ decision to vaccinate their children.
Despite the drop in measles cases reported in the UAE, doctors have warned the ant-vax movement is growing in the Emirates, as research published in May suggested as many as one in 10 parents are against inoculating their children.
