Misinformation is apparently being spread by parents which is affecting the judgement of others, Simon Stevens has said.
Mr Stevens also called the World Health Organisation’s decision to declare the UK no longer measles-free “worrying”.
Writing in the Daily Mail, Mr Stevens said: “Last week it was confirmed that the vaccination rate for two-year-olds getting their first MMR dose has dropped for the fifth consecutive year, hitting 90.3 per cent, leaving one in ten children at risk.
“Crucially, this rate is below the 95 per cent threshold where a critical mass of people is protected, creating a ‘herd immunity’ that keeps the whole population safe.”
Mr Stevens said the statistic was especially important because the lives of children who cannot be vaccinated – for example, if they are being treated for cancer – depend on other youngsters having had the vaccination to keep infection at bay.
He wrote: “With parents often taking their cue from other mums and dads, there must be a zero tolerance approach to misinformation, while the government’s strategy on improving vaccination levels will help to drive action…
“Dropped rates of vaccination mean many more people are vulnerable and exposed to risk, and all it takes for a whole society to be in danger is for one person to catch a disease and start a contagion.”
His intervention follows a similar warning this week from the government’s outgoing Chief Medical Officer who said she believed England should consider introducing mandatory vaccines.
Professor Dame Sally Davies said she hoped other measures could be tried first to stem falling immunisation rates, but it was vital to stop the spread of deadly diseases.
She said: “We need to up our vaccination rates. I hope we can do it by other means, but if we can’t, we might well end up with mandatory.”