Parents are refusing to give their children the flu vaccination over worries about its safety, research has shown.

Experts said that fraudulent research by the discredited former doctor Andrew Wakefield linking vaccines with autism could still be having an impact decades later.

Researchers from King’s College London found that two thirds of parents who did not vaccinate their child said that they were not convinced the vaccine had been tested enough to prove its safety. Twice as many parents who chose not to vaccinate had safety concerns compared with parents whose children did receive the vaccine.

According to Public Health England, uptake of the vaccine, given as a nasal spray, in children aged two to four dropped between 2014-15 and 2015-16. In the first year 39 per cent of two-year-olds, 41 per cent of three-year-olds and 33 per cent of four-year-olds were vaccinated. The next year the respective totals were 35 per cent, 38 per cent and 30 per cent. The health watchdog says levels should be at least 40 per cent.

Rates in those aged five to seven, reached through schools for the first time in 2015 to 2016, were between 53 and 54 per cent.

Louise Smith, from the National Institute for Health Research at King’s College London, said: “Something is happening that is making parents choose not to vaccinate their children.”

The study, published in the journal Vaccine, polled 1,001 English parents with at least one eligible child shortly after the end of the 2015-16 flu season. Parents who refused the vaccine were more likely to have concerns over safety, short-term side-effects and long-term health problems.

Sixty-five per cent of those who did not vaccinate thought that the vaccine “has not been tested enough for me to feel it is safe”, compared with 35 per cent of those who did vaccinate.

Ms Smith said that they also discovered parents were concerned that yearly vaccinations — necessary to protect against the particular strains of the virus in circulation — could “overload” their child’s immune system.

The researchers found that 53 per cent of those who did not vaccinate their child said they did not like vaccinations in general, and 60 per cent that the campaign was “just about making money for the manufacturers”.

David Robert Grimes of Oxford University, who has debated against Mr Wakefield, said there were numerous factors behind opposition to vaccines, “not least the long shadow of fear cast by Andrew Wakefield’s scaremongering over MMR in the late 1990s”.

Vaccination rates fell heavily after Mr Wakefield published a paper in 1998 wrongly claiming a link between the MMR vaccine and autism.

Helen Bedford, professor of child public health at University College London, said: “[Flu] can be very nasty in children. It is important to have the flu vaccine every year because the flu virus changes over time.”

Analysis
Giving children the flu vaccine protects them and the rest of us. Two years ago Dame Sally Davies, the chief medical officer, dubbed toddlers “super-spreaders” who could make whole families sick.

Young children are more likely to pass on germs because they have not yet learnt to cover their mouths and noses when they sneeze, do not wash their hands often and come into closer contact with other people than adults.

Healthy children under the age of five are more likely to have to be admitted to hospital with flu than any other age group.

While giving a child the vaccine does not guarantee they will not get flu, it makes it far less likely and also less severe if they do succumb to the virus.

However, curbing their ability to pass on the virus is most likely to ease the NHS’s burden. Health service bosses say that flu, which is harmful and potentially deadly in elderly or vulnerable people, is adding to pressure on hospital beds.

Research of this kind is trying to work out how to persuade people that vaccinating their child is for the best.

Previous studies have suggested it is very hard to change the mind of someone stubbornly opposed to the whole concept of vaccination.

However, the survey found that some parents allowed their children to receive the vaccine despite their concerns. Perhaps they were persuaded by the arguments for the greater good.