Full Fact secures measles correction from NHS England

We’re happy to say that NHS England has now published a detailed correction to its statement in January, which incorrectly claimed that “more than 3.4 million” children in England were “unprotected” against measles.

The correction follows months of work by Full Fact, and we hope it will now lead to further amendments by the health ministers Maria Caulfield and Lord Markham, and by many newspapers and broadcasters, who were misled by the NHS’s statement.

Measles is without question a highly contagious and potentially serious disease, and the MMR vaccine is a safe and effective way to protect yourself against it. But our investigation, which we published in March, explained two reasons why NHS England was wrong to say that 3.4 million children were unprotected.

Firstly, the figure included children who had received one dose of the vaccine, which would have protected many of them, even though they needed two doses to be fully protected.

Secondly, we established through a series of emails, and with a Freedom of Information request, that the figure of 3.4 million was a theoretical maximum for the number of children who might need to be contacted to check whether they were overdue a dose of the MMR vaccine. And there was reason to believe that many of these children were not overdue, but NHS England couldn’t be sure, because their records had degraded over time.

We don’t know how many children really were overdue an MMR dose, but our rough calculation using past vaccine coverage data and making moderate assumptions, produced a figure of around two million. (This is not a reliable estimate of the correct figure, but it does suggest the NHS figure was a substantial overestimate.) And of course many of them would have received one dose, meaning they weren’t necessarily “unprotected”.

The corrected NHS England statement now says “up to 3.4 million children under the age of 16 years are either unvaccinated or not fully vaccinated”, and includes detail on how that figure was reached.

The pandemic showed why it’s so important that people feel they can trust the information they get from public health bodies. But in order to be trusted, the NHS must act in a trustworthy way. This is one of the three pillars in the Office for Statistics Regulation’s Code of Practice for Statistics.

Obviously this means using accurate figures. But it also means being clear where those figures came from, and correcting them promptly when a mistake has been made.

Official statistics are widely trusted. Indeed until now, without a proper correction, it’s not been easy to convince people in politics and in the media that the NHS got this figure wrong. It even became the basis for another mistaken claim about encephalitis, which we fact checked recently. 

We are grateful to NHS England for reflecting on this claim and correcting it, following correspondence with us and the Office for Statistics Regulation.

We hope that the new correction helps to preserve public trust, and improves  trustworthiness in future.