Middle-class parents spreading false claims online are behind a dangerously low take-up of the measles vaccine in well-off areas, official figures unearthed by The Mail on Sunday reveal.

London boroughs, including Kensington and Chelsea and Camden, have seen rates for the measles, mumps and rubella vaccination (MMR) drop in the last four years, according to NHS data.

But childhood vaccination rates have held up well in more deprived parts of the country, including Barnsley, Bolton, Rotherham and Oldham.

Middle-class parents spreading false claims online have caused the low uptake on vaccines

The findings chime with previous research showing that online anti-vaccination posts are most likely to be written and shared by higher earners, and that the babies of mothers educated to degree level are most likely to remain unvaccinated.

Public health officials say vaccination rates need to be maintained at 95 per cent or above to achieve ‘herd immunity’, in which the entire population is protected against a particular disease.

Yet in Kensington and Chelsea, the uptake of the first MMR jab a child should receive – due when he or she is 12 months old – fell from 80 per cent in 2014 to 78 per cent in 2018.

In neighbouring Westminster, it also fell, this time from 79.5 per cent to 77.5 per cent. And in Camden, uptake of the first jab dived from 87.3 per cent to 80.2 per cent.

Years of below-average vaccination rates in North-West London are now feeding through to spikes in measles cases among schoolchildren and adults.

Since the start of April, there have been 65 confirmed cases in this wealthy part of the capital, according to Public Health England – three times the number the agency would expect. The worrying figure includes a ‘school outbreak’ that led to 31 people becoming infected with measles in the past two months, PHE said.

It sent a letter to the heads of all schools in the boroughs of Hammersmith and Fulham, Kensington and Chelsea, and Westminster, warning them about the ‘significant’ incident.

In Kensington and Chelsea, the uptake of the first MMR jab a child should receive – due when he or she is 12 months old – fell from 80 per cent in 2014 to 78 per cent in 2018

Years of below-average vaccination rates in North-West London are now feeding through to spikes in measles cases among schoolchildren and adults

However, in a host of towns in northern England, the percentage of babies given their first MMR jab has remained stable – Barnsley, for example, has maintaining a 96 per cent inoculation rate. Children must receive a second dose at three years old for maximum protection.

Dr Ellie Cannon, The Mail on Sunday’s resident GP, who practises in London, said: ‘Many of the mothers I see who are worried about vaccination are middle-class. They read around subjects, so are more likely to encounter spurious claims, such as jabs causing autism, or that giving babies combined vaccines such as MMR overloads their immune system. These misconceptions have been very damaging.’

Vaccine deniers – known as anti-vaxxers – emerged after former paediatrician Andrew Wakefield falsely linked MMR to autism in a discredited paper in The Lancet medical journal in 1998.

For most, measles is a minor illness but around one in 15 children who catch it will develop complications which can cause serious illness.

Measles cases in England more than trebled from 259 in 2017 to 966 last year.