BBC BLOGS - Mark Easton's UK
« Previous | Main | Next »

Why rising sex infection figures may be good news

Mark Easton | 17:34 UK time, Wednesday, 25 August 2010

Reading much of the press coverage of today's figures on sexually transmitted infections and the message is clear: the irresponsibility of our hedonistic teenagers is to blame for record levels of STIs. Some of the papers even have a photo of obviously promiscuous youngsters leering at the camera in case we don't get it.

But what the articles fail to stress is that the rise in diagnoses can be almost entirely explained by a massive increase in young people coming forward to be tested for chlamydia. And the proportion testing positive is actually going down.

Graph showing testing volumes and proportion of positive index cases by sex in England: April 2003 - March 2010

It is hardly a surprise that the NHS is finding more cases when its National Chlamydia Screening Programme (NCSP) [540.15KB PDF] has seen the number of tests rise from around a million in 2008 to 1.5m in 2009. An extra 500,000 young people are asked to pee in a pot and doctors discover an additional 14,000 cases of chlamydia and a handful of other infections.

The findings don't mean there is more sexual infection but that we have identified more of what there is. It could be that STIs are falling. We don't know.

When I was a teenager virtually no-one got tested for chlamydia. The number of people diagnosed was close to zero. That didn't mean chlamydia wasn't a problem. We simply hadn't looked to see how big it was. Chlamydia, after all, is an infection that can display few obvious symptoms.

When I asked the Health Protection Agency why their press release today does not mention the fact that the proportion of people testing positive for STIs is going down they gave me some complicated explanation about how the data comes from different parts of the organisation.

"It just happens not to be the way we calculate the data because we were combining GUM (STI) clinic and NCSP data," an official told me.


The release does quote Dr Gwenda Hughes who runs the Agency's STI section conceding that her people are "doing more testing, such as through the National Chlamydia Screening Programme, and some of the tests we are using for gonorrhoea and herpes are more sensitive, so as a result we are now picking up more infections."

But she then goes on to say that "the rise in STIs is also due in part to unsafe sexual behaviour". Well, of course it is. What we don't know, though, is whether there is more 'unsafe sexual behaviour' or less. Too high? Certainly. Getting worse? The evidence is far from compelling.

On the other hand, it is quite possible that the fall in the proportion of people testing positive for STIs is simply a factor of an expanding programme.

Indeed it does seem that the proportion of tests conducted through education establishments (where infection rates are around 4%) has risen a little while the proportion done in sexual health advice clinics (where rates are about 11%) has fallen. The programme has a target of screening 35% of all 16-24-year-olds in England so I suppose it is inevitable they will have to work harder to find willing recruits.

It is not, though, necessarily a justification for national hand-wringing.

That the chlamydia screening programme puts the level of sexual infection among 16-24-year-olds at around 7-8% is useful information. One might regard it as shocking, but without comparable data from other years or other similar countries it simply shows us the size of the challenge not the direction of travel.

The fact, though, that more than a million and a half young people agreed to have their sexual health checked out last year must be a positive sign. It is, arguably, evidence of a generation which has been persuaded to take its responsibilities in this regard much more seriously than its forebears who only went to the clap clinic when it was much too late.


or register to comment.

BBC © 2014 The BBC is not responsible for the content of external sites. Read more.

This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.