As I’ve written on many occasions, the HPV quadrivalent vaccine is one of the great achievements of medical science. It protects young men and women against the human papillomavirus (HPV), the most common sexually transmitted infection (STI) in the USA. There are over 170 subtypes of HPV; however, HPV subtypes 16 and 18 not only cause approximately 70% of cervical cancers, but they are linked to most anal (95% linked to HPV), vulvar (50% linked), vaginal (65% linked), oropharyngeal (60% linked) and penile (35% linked) cancers. HPV is estimated to be the cause of nearly 5% of all new cancers across the world.
One of the signs of HPV infection as a STI is the appearance of genital warts, and if there is a drop in the occurrence of genital warts in a population, we can assume that there could be a concomitant drop in the risk of these cancers. And we go back to the HPV vaccine, known as Gardasil or Silgard.
In an article just published in PLOS ONE, General Practitioners (GPs) in Australia are managing 61% fewer cases of genital warts among young women since the introduction of a national HPV vaccination program in Australia, which provides the vaccine for free. Read that carefully, if you’re a vaccine denier, or even more specifically one of those “I fully vaccinate my children, but I don’t think Gardasil is important, because my kids will NEVER be sexually active” types. A 61% reduction.
The actual data showed that presentation of genital warts to GPs fell from 4.33 per 1000 encounters in 2007, when the HPV vaccination program was introduced in Australia, to 1.67 per 1000 encounters in the period after introduction of the vaccine, from 2008-2012. Think about this another way–the risk of contracting HPV related genital warts was nearly 2.6X higher during the pre-HPV vaccine era in Australia.
Now, you might think that there’s some other thing going on in Australia to cause the drop. Except, in groups that were not covered by the HPV vaccine, say in individuals older than 30 or 40, the rate of genital warts was unchanged between the two periods, effectively acting as a control group.
The real world estimate is that the vaccine prevents 71 genital wart cases per 100,000 women and 21 cases per 100,000 men (not statistically significant) every year. And those 92 cases are at high risk of causing at least six types of cancers. And the article isn’t even looking at the saved cost to the health care system for fewer cases of genital warts and subsequent cancers.
“The results show that the program has been a widespread success,” stated the lead author of the study Christopher Harrison of the University of Sydney. “The program has proved to be a great success and of huge benefit to the sexual health of Australia, and has clearly proven to be very worthwhile.”
This article is a powerful one, including data from over 60,000 vaccinated individuals compared to nearly 400,000 control patients. This isn’t some garbage study, often pushed by the antivaccination cult, with a handful of patients or based on anecdotes. This is another in a long line of massively powerful studies of Gardasil that show it is clinically effective and clinically safe.
The authors of the study concluded that:
This study provides evidence that the quadrivalent HPV vaccination program has led to a decreased management rate of genital warts in general practice among those women of vaccine-eligible age. This study, along with those showing the decrease in diagnosis and management of genital warts in sexual health clinics and private hospitals suggests an overall community wide decrease in both the incidence of genital warts and its subsequent management. Due to this reduction, some young women in Australia have been spared the distress of having genital warts and the health system spared the cost of having to treat them.
This article tells me that Gardasil works, and a strong free vaccination program is effective, even over the short-term. In the USA, Gardasil is covered by most private insurance programs, and is fully covered by the Federally funded Vaccines for Children Program and Medicaid. In other words, the USA has an almost equivalent program, at no cost to patients, as Australia. Maybe we will have a similar type of study published using a USA cohort.
OK, we now have more evidence that Gardasil saves lives.
- Bzhalava D, Guan P, Franceschi S, Dillner J, Clifford G. A systematic review of the prevalence of mucosal and cutaneous human papillomavirus types. Virology. 2013 Oct;445(1-2):224-31. doi: 10.1016/j.virol.2013.07.015. Epub 2013 Aug 5. Review. PubMed PMID: 23928291.
- Harrison C, Britt H, Garland S, Conway L, Stein A, Pirotta M, Fairley C. Decreased Management of Genital Warts in Young Women in Australian General Practice Post Introduction of National HPV Vaccination Program: Results from a Nationally Representative Cross-Sectional General Practice Study. PLoS One. 2014 Sep 2;9(9):e105967. doi: 10.1371/journal.pone.0105967. eCollection 2014. PubMed PMID: 25180698.