Questioning the validity of blanket Gardasil vaccinations of pre-pubescent girls
Premature Inoculation [Originally published 2007]
On January 30, 2007, CBC online published a Canadian Press article quoting Dr. Shelley Deeks, executive secretary of Canada’s National Advisory Committee on Immunization (NACI). Deeks presents the committee’s recommendation that Canada adopt a blanket policy of vaccination of nine to 13 year old females to protect them from the Human Papillomavirus (HPV); she states: “girls aged nine to 13 who have not yet become sexually active should be immunized with Gardasil.” Gardasil is a recently approved vaccine produced by Merck Inc that protects against four of approximately 100 strains of the HPV virus in limited clinical trials. The premise of this paper is that the language of the online article formulates
an appeal to emotion in order to cultivate public endorsement of the vaccination program. On closer review of the data in the NACI Advisory Statement (NACI, 2007), a prudent parent will seek further assurances before enrolling their 9, 10, or 11 year old daughter into this program.
Larger issues beyond the scope of this paper undermine the foundation of blanket vaccination with this drug. Of immediate concern is the significantly short duration of the manufacturer’s study trials. In total the studies took place in an approximately five year period, which may not seem short in itself, however, the report is based on phased studies within that time period, with a post-last dose period of 4 years. As well, only 241 subjects were involved in the five year follow-ups (NACI, 2007). Another issue is the validity of the manufacturer having based safety and adverse effects results on comparisons of aluminum suspension placeboes rather than normal saline, hardly neutral; and at a time when aluminum suspension formulae are being scrutinized more closely (Bergfors, Bjorkelund & Trollfors, 2005). One cannot treat these concerns off-handedly as there is a danger in ignoring new information in medical science; the specter of thalidomide comes to mind. Considering the developmental stage of the target population, one might query how the long-term effects are being assessed for these girls.
Tell Someone… Everything
The inaccuracy of Deeks’ creative use of language cannot be overlooked. For example, using a hasty generalization she implies that the vaccine is safe for girls as young as five years old; however there is no evidence for that claim, and use in that age range is clearly discouraged in the statement of the agency she represents: “Immunogenicity or efficacy is not known for females < 9 years of age nor is the duration of protection from this vaccine. The vaccine is not recommended for this age group” (NACI, 2007). More succinctly, safety and efficacy are two different things and efficacy in nine to 15 year old girls is only inferred from bridging studies compared to data for women aged 16 to 26 years in the product studies; “the [16 to 26 year old] population for which both immunogenicity and efficacy data are available … are used to infer efficacy in the group in which only immunogenicity studies have been conducted (NACI, 2007).
Deeks goes on to unintentionally underline a key flaw in setting out a cost of the program, “Because we don’t know the duration of protection…“, leaving open the question of a booster program, which has not been ruled out (Elamin, Dasbach, Insinga, 2007). She further plays with the emotional purse-strings of the public to gain support stating: “Until such programs come into force, Canadians can obtain the vaccine through their physicians, but will have to pay the cost themselves” a red herring that diverts the public’s attention to lobbying for funding in anticipation of the program, a political maneuver that indirectly gains an individual’s endorsement of the program.
Deeks reasons that targeting these girls is justified, framing it by saying: “We recommended nine to age 13 because that’s the most likely period of time before females in Canada would become sexually active” however NACI (2007), whom she represents, presents a detailed analysis showing the average debut of sexual intercourse in Canadian youth to be 15.7 years of age “…1.1% reported having had sex by the age of 12 years, 3.3% by the age of 13 years” – statistics for boys were virtually identical.
This brings the appropriateness of carte blanche vaccination of the entire population of 9 -12 year old girls into question, given that the vaccine will have relevance for 2.31% of girls ≤13 years of age (70% effectiveness x 3.3). The numbers are further diminished to 1.73% when accounting for the article statement that 75% of women will get any of ≈100 HPV strains. Given also that HPV converts to cancer in <1% of cases (Singh, 2005) the potential risk for progression to cervical cancer for this group reduces to 0.017%. A wildcard in the matter is the fact that HPV can be passed vertically at birth, even in caesarean section births, and there is some suggestion that infection at this stage may be beneficial as an inoculant (Powell et al, 2003), and in other cases render the vaccine useless due to pre-infection, presumably there are some of either scenario in the target population as well.
There is little doubt that the vaccine is effective against the strains of HPV in the populations wholly tested as defined in the referenced articles. If the documentation is accurate, one can agree that the vaccine in its current state is a step in the right direction, and this paper is not intended to question that. It is, unfortunately, much more difficult to rule out risk of harm than it is to see targeted results, and for that reason an emphasis should be placed on the safety of the greater public. One must resist the tendency to leapfrog into a wholesale vaccination program for pre-pubescent girls at such an early date given the facts presented herein. Safety aside, the need for such a drastic age span has not been adequately documented. One might wonder if it is not sufficient to begin vaccinating at 12 years of age if, even by Deeks’ account, sexual activity commonly starts at 13 years of age, and in consideration of the extremely low degree of probability of 9-12 year olds contracting HPV through sexual contact. Canada’s approach makes that of the USA – vaccination optional before a program onset at 11 years of age – much more palatable.
A prudent nurse must exercise evidence based practice and therefore should not endorse the broad, disarming language of the article. In good conscience one cannot declare informed consent without first making every effort to convey all of the facts; indeed it would be unethical to do so. Ironically the Canadian Press article is not entirely useless for practice, as it may facilitate patient teaching if it inspires inquiry from a curious client and provide an opportunity to seek out appropriately evidenced facts. Finally, it serves as a reminder of the importance of evaluating the intention of information presented to us as health care professionals.
Bergfors, E., Bjorkelund, C., & Trollfors, B. (2005). Nineteen cases of persistent pruritic nodules and contact allergy to aluminium after injection of commonly used aluminium-adsorbed vaccines. European Journal of Pediatrics 164: 691–697 Retrieved from: http://0-web.ebscohost.com.innopac.douglas.bc.ca/ehost/pdf?vid=8&hid=106&sid=97757542-d58a-4a09-a2b1-32b413357fcb%40sessionmgr103
CBC (2007). Immunize females aged 9 to 26 against HPV: advisory committee. Retrieved February 6th 2007 from http://www.cbc.ca/health/story/2007/01/30/hpv-vaccine.html#skip300x250
Douglas College Department of Psychiatric Nursing (2000). Philosophy, New Westminster, B.C., Canada: Author
Elbasha E., Dasbach E., Insinga R. (2007) Model for assessing human papillomavirus vaccination strategies. Emerging Infectious Diseases. Accessed February 8th 2007 at http://www.cdc.gov/ncidod/EID/13/1/28.htm
Powell, J., Strauss, S., Gray, J., and Wojnarowska, F. (2003). Genital Carriage of Human Papilloma Virus (HPV) DNA in Prepubertal Girls with and without Vulval Disease. Pediatric Dermatology Vol. 20 No. 3 191–194, Retrieved February 10th 2007 from: EBSCOhost.
National Advisory Committee on Immunization (NACI). (2007). Statement on humanpapillomavirus vaccine. Accessed February 7th, 2007 at http://www.phac-aspc.gc.ca/publicat/ccdr-rmtc/07pdf/acs33-02.pdf
Singh, N. (2005). HPV and cervical cancer – prospects for prevention through vaccination. Indian journal of medical & paediatric oncology Vol. 26 No.1 20-23, Accessed February 10th 2007 at http://medind.nic.in/ias/t05/i1/iast05i1p20.pdf
 An argument that may in itself be valid, but which proves or supports a different proposition than the one it is purporting to prove or support (http://en.wikipedia.org/wiki/Red_herring_%28fallacy%29 )