Some thoughts about the HPV-vaccine
Within the small time period (5-6 years) of our knowledge, the vaccine seems to work well for the 4 HPV types (16, 18, 6, 11) and at present, it seems that it is not harmful for the individual.
On the other hand, there is a lot of uncertainty over its long-term effect and it is unknown whether it shall have all the argued positive results (a 70% decrease in cervical cancer incidence or so).
It is important to point out that we know very little about the HPV itself and it is also interesting that there are several variants of the HPV types, with differing health-risk patterns and with differing geographic distributions for each type (e.g. European, African, American and Asian variants for HPV 16 and 18). For example, a study showed that the risk of a subsequent CIN3 lesion was 3- fold greater for those women with the American than the European HPV-16 variant (*).
And this is the mystery. We don’t know the HPV’s role in the nature’s ecosystem and we don’t know what will be the nature’s response to a massive intervention to prevent a very common infection; since it is the persistent HPV infection that we want to fight with the vaccine and not cancer per se.
We cannot predict the future accurately and especially what will happen in 30-40 years time. Moreover, our current mathematical models may not be able yet to calculate all possible scenarios. For example, an unlikely but not impossible bad scenario would be that, after the implementation of the HPV-vaccine, the nature might “replace” them with some of the other oncogenic HPV types such as 53, 56 etc. (as happens with microbial populations when treated with antibiotics). In this case, the effect of vaccination would be almost negligible and all the scarce resources allocated to HPV-vaccination would have been wasted.
Certainly, the HPV-vaccine technology is very promising and probably it will provide future weapons for cancer control. However, a critical question is whether the taxpayers can afford now an expensive technology for an unknown future effect.
In addition to all the above, cervical cancer in Western Europe and in other developed countries is not such a major problem as compared with other countries where incidence and mortality are multifold (i.e. Mexico, Brazil etc.).
No doubt, cervical cancer for the individual is a major threat. The society however, has to balance its scarce resources and the huge funds, allocated for a vaccine that is still under study, might be more effective if used in other areas of disease prevention (e.g. improvement of the current cervical cancer screening programs, the prevention of heart disease or of car accidents etc.).
In my view, the reaction of several “western” governments to implement the HPV-vaccine was rather premature and certainly they could have waited for a few years until more knowledge transpires (at least until solving the question of a boost dose). Nevertheless, the way the HPV-vaccine was announced, licensed and rolled-out created an irreversible demand.
But wait. In 30-40 years time we shall learn the truth.
(*) “Risk for high-grade cervical intraepithelial neoplasia associated with variants of human papillomavirus types 16 and 18“, Long Fu Xi, Koutsky Laura A., Hildesheim Allan, Galloway Denise A., Wheeler Cosette M., Winer Rachel L., Ho Jesse, Kiviat Nancy B., Cancer epidemiology, biomarkers & prevention, vol. 16, no1, pp. 4-10, January 1, 2007.
(Abstract: http://cebp.aacrjournals.org/cgi/content/abstract/16/1/4, and free full text access/ last visit 12 June 2008).
art. added Apr. 2010: “Abnormal Pap tests after the HPV vaccine“, Heley S, Brotherton J., Aust Fam Physician. 2009 Dec;38(12):977-9. (Abstract, free full text , access/ last visit 10 April 2010)
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