Texas governer Rick Perry has recently signed an Executive Order requiring all girls between the ages of 11 and 12 to be vaccinated with Gardasil, Merck’s new HPV vaccine, which is currently the only vaccine on the market that treats HPV (other HPV vaccines from other companies are in the pipeline and soon to be approved by the FDA). In response to this, Texas legislators have recently proposed a new bill to remove Gardasil from the vaccination list required by TX law for entry into public school.
Governor Perry’s Executive Order has kicked up a lot of dust. While many people initially opposed universal HPV vaccination under the premise that it would encourage promiscuity in teenagers and women, concerns about the safety of the vaccine, as well as its long-term effects, have also been raised. From a legal standpoint, many people feel that requiring HPV vaccination for entry into school is an enfringement on their rights, particularly since the public health need for this vaccine is not as pressing, given that HPV is not an airborne or contact communicable disease that can be transmitted at school, but is actually an STD requiring genital to genital contact, and the rates of cervical cancer in this country are actually very low (annual pap smear screening for cervical cancer is one of our greatest public health success stories!). Questions have also been raised about the motivation behind this vaccine, given that Merck was a contributor to Perry’s campaign fund, and Merck alone stands to profit from routine vaccination of all girls in Texas, which the New York Times is estimating will cost at least 60 million.
Rachel over at Women’s Health News has posted three very thoughtful posts about this new law which encapsulate much of the current debate. The comments from her readers in particular are very telling:
For my own part, I would like to address some of the misinformation about the HPV vaccine that is floating around right now. From a reader on Rachel’s site who was arguing against universal vaccination: “…2) There are 15 types of HPV. The vaccine, created by Merck, which has received so much media attention, protects against 2 types of HPV. These two types are implicated in causing 70% of the cervical cancers that develop. 30% are caused by the 13 other types of HPV which this vaccine is no protection against.”
There are actually over 100 genotypes of HPV which have been discovered to date, of which approximately 30 strains are found in the genital mucosa. Of those 30 strains, 15 have been shown to be associated with cervical cancer, in particular types 16, 18, 31, 33 and 35. These types are considered the “high risk” strains and are usually subclinical/ non-detectable. Approximately 70% of cervical cancers result from infection with HPV genotypes 16 and 18. In contrast, HPV types 6 and 11 are considered “low risk”, and are responsible for 90% of all cases of genital warts (i.e. highly clinically detectable). HPV is spread through direct genital to genital contact, and can be transmitted even when using a condom, since a condom does not cover the entire genitalia.
Gardasil is a quadrivalent human papilomavirus L1 virus-like particle vaccine which offers protection against HPV genotypes 6, 11, 16 and 18. In other words, the two strains that are most often responsible for cervical cancer, and the two strains that are most often responsible for genital warts.
However, as many readers have pointed out, Gardasil only offers protection for 2 of the 15 genotypes associated with cervical cancer and only 2 of the genotypes that cause genital warts, and the research is not conclusive on how long Gardasil is able to offer protection, or whether booster vaccines will be needed at a later date. It is also important to note that all of the research on this topic has been funded and carried out by Merck. Most importantly, the pap smear has been a highly effective screening tool for cervical cancer since the 1960s, responsible for early detection and treatment of cervical dysplasia, and the number one reason why cervical cancer rates are so low in this country (although still disproprotionate: cervical cancer rates are highest for low income and uninsured women). Worldwide, cervical cancer is the second largest cause of female cancer mortality, with an estimated 493,00 new cases each year and 274,000 annual deaths. In other words, even if you do choose to be vaccinated with Gardasil, annual pap smears are still crucial.
It will be interesting to see how this plays out, both in the media and in the legislature. It will be interesting to see if other states follow Texas’ lead. The HPV vaccine is an extraordinary breakthrough, the first vaccine ever created that actually targets cancer, but as with any new vaccine or drug touted as a new miracle, I think a little caution in the beginning is well founded, since new research is still incoming and the long-term effects are unknown.
Source: ACOG (Sept., 2006) ACOG Committee Opinion #344: Human Papillomavirus Vaccination. Obstetrics & Gynecology, 108 (3), Part 1: 699-705.