Tuesday, 11 October 2016

Gardasil in the balance

Part I; this is part II on HPV. Dr Brenda Corcoran from the HSE's National Immunisation Office was on the wireless last week precipitating a bit of heat over the dinner table that evening. Yesterday, I offered the reasoning (there's little evidence) for the anti-vax position which we have, at one time, taken. You can't really expect the head of the National Immunisation Office to be against vaccination, so anyone with a crap-detector should be a little bit skeptical about what she says. Nevertheless, after the skepticism, you may conclude that the balance of probabilities lies with getting your almost teenage daughter injected with viral proteins to stimulate a lasting immune response against Human Papilloma Virus HPV.

You will, of course, put aside the fact that the cost to Ireland [I pay tax here, so am footing your bill] is €600 for a three-stab course of Gardasil, Merck's highly effective therapy against HPV. We should also give parity of esteem to Cervarix, GlaxoSmithKline GSK's equivalent vaccine against the two cancer associated strains of HPV. In Ireland the treatment is offered for free to girls as they enter 2ndry school: if you fail to take it up then, it will be an expensive proposition later. No pressure! Something like 200,000,000 doses have been distributed world wide since 2006; not all at the same profit-making price as in affluent Ireland. Nevertheless, that's a market worth something in excess of €10 billion, so there is a lot of push-back on any suggestion that, while Gardasil demonstrably works against HPV, it may also be responsible for some most unfortunate side-effects in some girls. Another angle on that is that Merck have shifted 600,000 doses [for 200,000 girls - the effective dose was a threefer but is now a twofer] in Ireland, almost all through the largesse of the government. So me-the-taxpayer has enriched Merck to the tune of €120 million.

That's a lot of sugar, so there should be some pay-off.  It seems that 70% of cervical cancers can be laid at the door of two strains, HPV16 & HPV18. According to Dr Corcoran, Ireland has 300 cases and 90 deaths from cervical cancer each year, so we may guesstimate that full take-up of HPV vaccination would prevent 200 cases and 60 deaths a year. The difference between incidence and death is due to surgery, chemotherapy and other expensive and invasive interventions. There are 30,000 girls in each teenage year cohort so the cost of this prevention is €18 million or €300,000 per preventable death. Put that in the context of other expensive therapeutics for which the HSE picks up the tab: €150,000 per year for melanoma; a fantastical €400,000 per year for each of the 5 Irish people with Morquio Syndrome.  The bill for Ireland's haemophiliacs is greater, despite their therapy being a little less [€300,000pa], because there are more [N=200] of them. Podcaster William Campbell gives a more chilling but useful view of the incidence of cervical cancer: a yearly rate, as used by Dr Corcoran, is out there somewhere happening to other much older women. Campbell says that your lifetime risk of contracting cervical cancer is 1:115.  Me, even knowing that the Mumps jab didn't work, I'd put Dau.I and Dau.II through a couple of jabs now to minimise that 1% risk of something so dire. Whether it's worth €600, though, hmmmm?

But let's also put it in the context of other forms of prophylaxis . . . like condoms. Although the facade of HPV vaccination is about preventing cervical cancer by preventing HPV infection, little is said about how you get exposed to HPV in the first place. It's a sexually transmitted disease, folks! Indeed it is the most common STI we know of: by their early 20s, 80% of girls will test positive for HPV. Most of that will be the 100+ types of HPV that doesn't cause cancer and most of them will get cleared up nicely by the immune system. It's not just cancer: HPV6 and HPV11 will significantly increase your risk of acquiring a flush of genital warts. They are mostly harmless but unsightly; although who would call human genitals pretty? Not for nothing do some folks use the phrase bumping the uglies. Maybe if we invested a fraction of the Merck/GSK pay-out into education and somehow shifted the focus of society from wall-to-wall sex, we'd get fewer cases of cervical cancer but also fewer teen pregnancies and fewer cases of clap . . . chlamydia . . . crabs . . . syphilis. Actually a lot could be done just by heeding the advice of Dr Derek Freeman about what constitutes safe sex: If you don't have his phone number you shouldn't be bonking him. But that's not going to happen because the HSE is not about health - it's about disease and cures: the higher the tech the better.

Do you also have a sense that the low-hanging fruit of medical therapies are all gone? in the 1950s, 7,000 new cases of TB were notified in Ireland annually. Smallpox is gone. Polio too: in 1942 there were 487 Irish cases and 133 deaths. Now we're working hard on comparatively rare conditions.

Clintons are in the news a lot this week, and we've heard rather more than we need of not-news about Mr Clinton's sense of alpha-male entitlement to lots of sex with lots of women. Those of a certain age will remember his weasel-words I did not have sexual relations with that woman . . . Ms Lewinsky and the storm of comment about what constituted sexual relations. I don't know how it was in 1816 or 1916 but the CDC currently claims that 80% of people have engaged in oral sex with the opposite sex. Women want to be a little careful about what sort of not-sexual-relations they have with their blokes. HPV type-16 is associated with pharyngitis [infection of the throat] and some cases of this can go on to develop into oropharyngeal cancer. HPV-driven oropharyngeal cancer is 3x more common in women than men.

 In risk assessment you want to gauge both the severity of an outcome and its likelihood. The product of (severity x likelihood) gives you, and governments, guidance about where and how much you should intervene to avoid particular outcomes.

Bottom line in HPV-vax? Dr. Bob says embrace the opportunity: it's free and it will help prevent a rare but devastating cancer later on.

No comments:

Post a Comment