You sure, Mike?

Holly Baxter writes an interesting article on the Michael Douglas/HPV story (widely covered in the past few days: eg here, here or here) in today's Guardian, in which she basically tries to steal our thunder...  ;-) 

Holly argues that Douglas' conclusion that his recent throat cancer was due to his continued practice of cunnilingus (and subsequent HPV infection) is in fact not quite granted. She rightly points out to other risk factors, which seem to have an even bigger impact on the occurrence of HPV. Also, she rightly mentions that while cervical cancer is almost completely caused by HPV, other tumours (such as throat cancer) are affected by it, but not to the same degree.

I think her comments are pretty much in line with the approach we have taken for our study on HPV vaccination (which I have mentioned for example here and here). As part of the research, we have conducted a sample survey on about 600 individuals and have tried to identify potential risk factors (we're writing up results and hopefully will have something soon!) and, as it turns out, the main issues are:

• sexual promiscuity;
• smoking and early sexual debut;
• education

all of which increase (to various degrees) the risk of HPV acquisition.

In addition, Holly argues that male vaccination is an important issue $-$ of course we agree and in fact, the (Bayesian Markov) model we're currently finalising tries to assess whether offering universal vaccination (in our case to boys and girls aged 12) turns out to be cost-effective. 

On that, however, I think the jury is still out. From our (semi-finalised) results, there may be a potential for cost-effectiveness in universal vaccination (which would mean reducing the overall number of subjects potentially at risk, because of the effects of herd immunity, which we are accounting for in our model). However, the results seem to be sensitive to some of the parameters for which the evidence available is very limited.

I'll post more once we've finished our analyses.