Measles

The measles vaccine, which is included in the MMR jab, is a safe and effective way to stop the disease.

Ideally everyone should be immunised, but the target set by health experts is at least 95% of the population vaccinated.

The UK achieved this in 2016, when the World Health Organization declared the nation measles-free.

That did not mean that measles had been wiped out entirely, just that none of the cases originated in the UK.

But that has now changed. The UK has lost its eliminated status and measles cases are on the rise.

 Experts say that until measles elimination is achieved globally we will continue to see cases of measles coming to the UK.

Two doses of the vaccine leaves 99% of people protected - the majority of new measles cases have been in people who are not vaccinated. These cases are most common among older teenagers and people in their early 20s, who missed out on MMR vaccination when they were younger. 

Measles circulates in many countries around the world, and there are currently several large outbreaks across Europe in countries where rates of MMR vaccination have been low. 

As measles is highly infectious, even small declines in vaccination rates can have an impact, and anyone who has not received both doses of MMR is at risk.

Just 87% of children in England are receiving their second dose of MMR. In Wales and Scotland it is around 92%, in Northern Ireland it is 91%. The target is 95%.

In London, estimates suggest about one in four children starting primary school do not have the full protection that the MMR vaccine offers.

For several years global coverage with the first dose of measles vaccine has stalled at 85%. Second dose coverage, while increasing, is 67%.

An estimated 20 million measles cases and 4,500 deaths have been prevented in the UK since a measles vaccine was introduced in 1968.