PEOPLE failing to vaccinate their children against measles is a 'growing public health timebomb', the head of the NHS has warned.

Cases of measles – which can cause disability and death – have quadrupled in England in just one year.

More than half a million children in the UK were not vaccinated against measles over an eight-year period, new figures show.

Why is it happening?

The charity Unicef said increasing numbers of youngsters are being left unprotected against measles, which can cause disability and death.

Inaccurate and misleading anti-vaccination messages on social media are thought to be one reason why vaccination rates are plummeting.

Simon Stevens, chief executive of NHS England, said: "Getting yourself and your children vaccinated against killer diseases is essential to staying healthy, and vaccine rejection is a serious and growing public health timebomb.

"With measles cases almost quadrupling in England in just one year, it is grossly irresponsible for anybody to spread scare stories about vaccines, and social media firms should have a zero tolerance approach towards this dangerous content."

What are the signs to watch out for?

The NHS says the initial sympoms can include:

runny or blocked nose

sneezing

watery eyes

swollen eyelids

sore, red eyes that may be sensitive to light

a high temperature (fever), which may reach around 40C (104F)

small greyish-white spots in the mouth

aches and pains

a cough

loss of appetite

tiredness, irritability and a general lack of energy

The measles rash

Spots in the mouth

What vaccinations do children need?

Children need two doses of the vaccine for protection, with the World Health Organisation (WHO) recommending 95 per cent coverage to achieve herd immunity, which offers protection against the disease spreading in the community.

Herd immunity works when a sufficient amount of the population is immune, preventing the spread of infection.

In the UK in 2017, there were 259 measles cases in England, rising to 966 in 2018.

In 2016 and 2017, uptake of the first dose of the MMR vaccine in five-year-olds in the UK exceeded 95% for the first time.

However, two doses of MMR vaccine are required to ensure full protection from measles.

Uptake of the second dose of MMR in five-year-old children is 88% - well below the 95% WHO target.

Figures from October to December 2018 show nine out of 10 children received their first dose by age two, rising to 95% at age five.

By age five, 87% had had their second dose, the quarterly figures showed.