Misnamed anti-vaccine website Child Health Safety posted a blog recently in which a number of surprising claims were made with great certainty. I thought these claims sounded very dubious and it turned out that they were. It’s taken me a few days to get round to posting this debunking partly because, unlike Child Health Safety, I like to check my facts before I publish.
Here, Child Health Safety looks at the recent outbreak in Wales and makes a number of confident assertions that turn out to be untrue. It is claimed that measles has been “18,200% over-diagnosed” and “0.005 of notified measles cases were really measles” in March. There are similar claims made for other time periods, including the claim of 26 confirmed cases out of 446 in the first quarter of 2013. CHS boldly proclaims that “Now you can see the extent of the scam being run by public health officials in Wales, UK.” (There is another claim shortly after this: “You can rely on good old CHS because we let you check out the figures here all by yourself.”) Following this, links to NHS documents are posted by CHS. That’s right – the proof of the scam apparently comes from documents made available to the public by the alleged scammers themselves! I’m a little surprised that even CHS didn’t pause for thought at that point.
The two documents show notifications and confirmed cases of measles. In the comments, CHS makes it clear that they believe that all notifications have been tested and that a tiny percentage were actually measles, with all others testing negative for the disease: “All notified cases are laboratory tested. So basically Public Health Wales have been telling whoppers.” This claim is based on HPA guidelines that state that “Since November 1994, enhanced surveillance including oral fluid testing of all notified and suspected cases has been provided through the Centre for Infections.” While the guidance does suggest that testing should be undertaken for all notified and suspected cases, this doesn’t mean that it was being undertaken for all cases in the Welsh outbreak of measles.
I emailed Public Health Wales to ask them whether lab testing had been carried out for all notifications in this outbreak. They helpfully emailed me back with clarification:
It is certainly not the case that we have laboratory tested all measles cases in the current outbreak. Although some cases have been laboratory confirmed (370 at present), the majority of our cases are notified cases, meaning that we are satisfied they are measles based on clinical diagnosis by a GP or other health professional, without requiring testing to be undertaken.
There’s more. CHS had claimed (in bold, underlined text) that there were just 26 lab-confirmed cases of measles in the first quarter of 2013, out of 446 notifications. The 26 laboratory confirmed cases referred to are those confirmed in laboratories in Wales in the first three months of 2013.
The majority of laboratory tests conducted for measles during that period were actually undertaken by our colleagues in Public Health England, and therefore those confirmed in England do not show up on our own laboratory reports and are not included in the figure of 26.
Child Health Safety had the data on lab-confirmed cases, the data on notifications and the guidelines on testing. What they did was to assume that (a) they had all the relevant information and (b) they had correctly interpreted it. What they didn’t do was take the time to ask for clarification. If they had, they would have discovered that they had misconstrued the figures relating to measles notifications and confirmations. They would also have discovered that their assumptions regarding testing, while based on the guidelines issued, were unwarranted. They screeched about a “scam” and “whoppers” but these were of CHS’s making – they have no basis in reality and CHS could have discovered this relatively easily by simply contacting Public Health Wales and asking for some clarification.
Now that I have done what CHS should have done in the first place, I hope that a prominent correction will be issued by Child Health Safety on their blog. I also think that an apology to Public Health Wales for the false allegations made in that misconceived blog post would be appropriate.
I won’t hold my breath.
13th May, 2013: there’s a remarkable performance in the comments section below from Child Health Safety. I’ve never seen such a potent mixture of weaselly obfuscation and stubborn denialism. The attempts to argue that black is white and up is down really are something to behold. I said I hoped for a prominent correction on CHS’s part and an apology to Public Health Wales for the false smears. It is quite clear that CHS will never admit to having erred. If you know CHS, do please encourage him to read this book.
9th June, 2013: more on this from Just The Vax.