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Gardasil and Sexual Disinhibition: Does HPV Vaccination Increase Sexual Promiscuity?

By Miriah Martin

October 5, 2009


          Gardasil is a prophylactic vaccine developed by Merck & Company for the prevention of HPV-related infections, which collectively have a high disease burden and are transmitted sexually. Following the release of the vaccine in 2006, many groups, especially social conservative organizations, expressed concerns regarding the potential for Gardasil to encourage sexual promiscuity in young adults. The purpose of this paper is to determine the validity of those claims. Despite the fact that research on the specific relationship between Gardasil and sexual disinhibition (i.e., increased risky sexual behavior) is currently unavailable, studies addressing similar questions strongly suggest that Gardasil would not increase sexual promiscuity.


Background Information


                   Picture 1. The HPV virus.

          The HPV Virus

Human papillomaviruses (HPV’s) are double-stranded DNA viruses that can cause cervical and anogenital cancers, genital warts, and recurrent respiratory papillomatosis (Markowitz et al., 2007). The primary route of viral transmission is genital contact, especially sexual intercourse. Other modes of transmission including non-penetrative sexual contact and gestational transmission have been reported, but are much less common. Nearly 100 strains of HPV have been discovered, and are classified based on their oncogenic (i.e., cancer-causing) properties. For instance, HPV types 6 and 11 are considered low-risk, as they produce only benign alterations in cervical cells, whereas types 16 and 18, which cause an estimated 70% of cervical cancers worldwide, are categorized as high-risk. Findings show that the high-risk HPV strains are present in 99% of cervical cancers .The forty HPV types associated with genital infections are responsible for an estimated 6.2 million newly diagnosed cases per year in the United States alone, making HPV the most common sexually transmitted infection (STI) both in this country and worldwide.


HPV Disease Burden

In addition to the high incidence of HPV infections, the disease burden has created devastating effects both nationally and globally. Current studies indicate that at least 50% of all sexually active individuals will eventually become infected with HPV, and up to 80% of women will have contracted the virus by age 50 (Saslow et al., 2007). With regards to annual HPV-related mortality in the United States, the American Cancer Society estimates that there are 3,700 deaths from cervical cancer (99% caused by HPV), 620 deaths from anal cancer (90% caused by HPV), and 870 deaths from vulvar cancer (40% caused by HPV). Additionally, there are over 500,000 newly diagnosed cases of anogenital warts yearly, 90% of which are caused by HPV strains 6 or 11. On a global scale, cervical cancer ranks second as the deadliest cause of cancer death in women, and in developing countries that lack modern screening technology, cervical cancer is usually the most prevalent cancer in women. As a result, there are an estimated 288,000 deaths annually from cervical cancer worldwide. Although cervical cancer incidence and mortality rates have decreased following the introduction of the Pap test in 1949, ethnic, racial, and cultural disparities still exist in resource-poor populations.


Gardasil: Development and Mechanism of Action

In response to this high-HPV related disease burden, Merck & Company and GlaxoSmithKline developed two prophylactic vaccines intended to reduce infection and mortality rates (Saslow et al., 2007). Gardasil, the vaccine marketed by Merck & Company, was licensed by the FDA in June of 2006, and in clinical studies, has been shown to protect against HPV strains 6, 11, 16, and 18 (quadrivalent). Gardasil does not contain live or attenuated viruses, and has the following mechanism of action: proteins resembling the outer surface of the HPV virus assemble and subsequently elicit a specific and sustained immune response against the actual virus. According to the Gardasil website (, the vaccine is given as three intramuscular injections over a six month period, and is currently intended only for women ages 9 to 26, though research is currently being conducted into possible applications for men. The website states that Gardasil does not treat HPV infections, does not fully protect everyone, and cannot protect against other forms of HPV in addition to the ones mentioned in the quadrivalent. The common side effects listed include injection site pain/ discoloration, fever, vomiting, and others, but do not list any life-threatening conditions other than the signs of a possible allergic reaction to the vaccine.


Current Controversies


                                 Picture 2. Although men are susceptible to HPV infections,

        Gardasil is currently available only for women.


Despite the promising prospect of Gardasil, some organizations have expressed concerns regarding the potential negatives consequences of making this vaccine universally available. These concerns have included issues of safety, efficacy, sustained immunological response, vaccination of young men, mandatory vaccination for school entry, and possible sexual disinhibition. Following the CDC’s inclusion of the HPV vaccine on their vaccination schedule (, speculation of Gardasil’s safety and efficacy seems to have decreased. According to a report by the CDC’s Advisory Committee on Immunization Practices (ACIP), there is currently HPV-vaccine safety data available from seven clinical trials, which collectively reported serious adverse effects in less than 0.1% of trial participants (Markowitz et al., 2007). In the group of vaccinated participants, only ten deaths were reported, all of which were determined to be caused by an event unrelated to the vaccine such as an automobile accident. Similarly, three clinical studies on the efficacy of the HPV vaccine showed a high effectiveness in preventing the four specified HPV types in female participants who had received the recommended three doses of the vaccine.

The validity of the other aforementioned concerns is less straightforward due to the ongoing HPV vaccination research and/ or the subjectivity of the issues in question. With regards to sustained immunological response, Merck & Company is still in the process of conducting longitudinal studies to determine the specific duration of protection (Markowitz et al., 2007). Data from one of those studies in its third year indicated a nearly 100% efficacy against certain HPV-related infections. Similarly, studies are currently being conducted to determine the vaccine’s safety and effectiveness for young men, but Gardasil is still recommended only for women at this time. The final two concerns expressed, which include mandatory vaccination and possible sexual disinhibition, are interrelated concepts. If person believes that vaccinating young women with Gardasil will increase their sexual promiscuity, then that individual will most likely conclude that the vaccine should not be mandated for school entry. In recent years, however, many socially conservative organizations such as the Family Research Council ( and Focus on Family ( have released statements publicly accepting the health benefits of the vaccine while simultaneously rejecting mandatory vaccination for school entry on the grounds that doing so would infringe upon parental rights. Even with this limited acceptance of Gardasil, the question of whether or not a prophylactic HPV vaccine could increase sexual risk-taking behavior must be addressed in order to ensure that the wide-ranging health benefits of Gardasil are not diminished by unsubstantiated claims.


Concerns of Sexual Disinhibition


                                                  Picture 3. Some groups fear that Gardasil

                                                  will undermine their abstinence messages.

Before exploring the validity of these sexual disinhibition claims, it is useful to consider both their origin and specific content. An article published in the Washington Post provides a fairly comprehensive overview of the conservative opposition to the vaccine just prior to Gardasil’s release in late 2005 ( The author states that because the virus is transmitted primarily through sexual contact, “…many conservatives oppose making it mandatory, citing fears that it could send a subtle message condoning sexual activity before marriage”. He further elaborated on this point by citing individuals involved in the debate who worked closely with conservative organizations. Dr. Reginald Finger, who was previously a medical analyst for Focus on the Family, agreed that, "Some people have raised the issue of whether this vaccine may be sending an overall message to teenagers that, 'We expect you to be sexually active,' ". Similarly, Gene Rudd, associate executive director of the Christian Medical and Dental Associations, reported that, "I've talked to some who have said, 'This is going to sabotage our abstinence message,' ". Interestingly, these fears of sexual disinhibition were not limited to conservative organizations. According to the article, the ACIP surveyed 294 pediatricians in order to get physicians’ perspectives on vaccinating young women. Surprisingly, 11% of the pediatricians rejected the idea of STI vaccinations on the grounds that they "may encourage risky sexual behavior in my adolescent patients."

A study by Olshen et al. (2005) indicated that this public debate on the behavioral effects of the HPV vaccine affected parental perceptions as well. Focus groups and individual interviews regarding attitudes toward HPV vaccination were conducted with twenty-five parents recruited from urban, private pediatric and adolescent clinics. The results of the study showed that many parents would choose to discuss whether or not to get their child vaccinated with their child’s pediatrician before making a final decision. Furthermore, many of the parents expressed concerns regarding intimate discussions with their children about the HPV vaccine, and more importantly, many parents also harbored fears of the vaccine’s potential to promote unsafe sexual practices. These conclusions are not surprising considering the previously mentioned results of the ACIP survey of pediatricians.

These concerns of sexual disinhibition have persisted following Gardasil’s release in some capacity, and probably continue to underlie most conservative opposition to Gardasil. However, it is difficult to find many organizations that continue to publicly state a direct causal increase in sexual promiscuity as their specific reason for rejecting mandatory vaccination for school entry, as there is general lack of evidence to support such a claim. Concerned Women for America (CWA), a group that strives to preserve Biblical values, is one of the few organizations that currently does oppose mandatory HPV vaccination on the grounds that “Giving the vaccine to young girls before they are sexually active provides them with a false sense of security, possibly leading to risky sexual behavior that would not have occurred had the threat of cervical cancer been present” ( As mentioned previously, other organizations, such as Focus on Family, emphasize the infringement of mandatory vaccination on parental rights while still maintaining nuances of sexual disinhibition claims in their educational pamphlets. In one such pamphlet entitled “Talking to Your Children About the HPV Vaccine” (, the author states that vaccinated individuals may say, “It’s safe and okay now [emphasis added] to have sex”, which implies that post-vaccination attitudes could be of a more promiscuous nature.


Research on HPV Vaccination and Risk Behavior


                                                  Picture 4. Research on the relationship between

                                    Gardasil and sexual behavior is still in progress.


Although these sexual disinhibition claims could greatly hinder the health benefits of Gardasil in the future, there are currently no studies specifically studying risk-taking behavior in vaccinated individuals, though there may be some studies in progress. Considering the vaccine’s novelty, this is to be expected. Despite this, there are studies that provide comparative evidence to help address the question of whether or not Gardasil could encourage sexual risk-taking behavior.

One such study by Brewer et al. (2007) aimed to explore the theory of risk compensation in the context of behavior resulting from vaccination. The theory of risk compensation proposes that protective factors, such as vaccination, lower risk perception in individuals, and consequently, those individuals compensate for that lowered risk perception by reducing certain protective behaviors. The protective factor in this study was the Lyme disease vaccine, which, like Gardasil, does not fully protect everyone who is vaccinated. Although there are significant differences between Lyme disease and HPV-related conditions, the fundamental principles of behavioral disinhibition were the primary focus in this case. Over 700 participants in an area with high Lyme disease incidence were surveyed to determine if they continued to engage in certain protective behaviors, such as wearing insect repellant and long clothing, following vaccination. The results showed evidence of regression (i.e., frequency of protective behaviors decreasing to levels of the unvaccinated cohort), but not of behavioral disinhibition (i.e., risk-taking behavior exceeding that of the unvaccinated cohort). These results suggest that individuals vaccinated with Gardasil would most likely not display increased sexual risk-taking behavior on a level above that of unvaccinated individuals.

Comparative evidence may also be derived from a meta-analysis conducted by Smoak et al. (2006), in which the experimenters wanted to determine if condom-related interventions aimed at HIV risk reduction resulted in increased sexual behavior. Again, there are some dissimilarities between condom use and Gardasil, but a change in attitudes toward STI’s and sexual behavior is the significant common factor in this case. Data was collected from 174 studies and included 206 interventions with 116,735 participants. The results showed that these interventions did not increase the overall frequency of sexual activity, and for some high risk participants such as African Americans, actually reduced the number of sexual events and partners. These conclusions provide further evidence against the claim that Gardasil would create a false sense of security in young adults.

While both of these studies are studies are helpful for comparative purposes, a study by Marlow et al. (2008) investigated mothers’ and daughters’ attitudes specifically with regards to the principles of risk compensation in the context of HPV vaccination. Approximately 330 mothers and 360 adolescent girls took surveys that measured their beliefs on HPV vaccination and scored their responses using the risk compensation scale. Only a small minority of the participants, specifically those with lower knowledge of HPV, reported that they thought HPV vaccination would increase the chance of risky sexual behavior. Interestingly, most of the adolescent girls believed that they would personally have low risk compensation while the risk compensation in the general population would be higher. This is not surprising considering the fact that knowledge of HPV as an STI has been found to be extremely limited (Saslow et al., 2007).



          Despite the lack of specific studies exploring HPV vaccination and risk-taking behavior, the evidence from studies testing risk compensation in the context of similar protective factors appears promising. The claim that Gardasil encourages sexual promiscuity is based on the assumption that young adults, who are either abstinent or who are having sex less frequently, do not engage in promiscuous behavior primarily or solely because they concerned about contracting HPV. Data from the National Survey of Family Growth shows that a mere 10% of adolescent boys and 7% of adolescent girls who abstain from sex reported “don’t want STD” as their primary reason for continued abstinence (Saslow et al., 2007). Thus, if the majority of young adults are not concerned and/ or not aware of the risks of STD’s, then there is no reason to anticipate changes in their sexual practices in the presence of an added protective factor such as Gardasil. Even in light of this reasoning and research-based evidence, the question of Gardasil’s effect on risk-taking behavior necessitates further investigation for more conclusive answers.




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Brewer, N.T., Cuite, C.L., Herrington, J.E., Weinstein, N.D. et al. (2007). Risk Compensation and Vaccination: Can Getting Vaccinated Cause People to Engage in Risky Behaviors? Ann Behav Med; 34(1):95-99.


Markowitz, L. E., Dunne, E. F., Saraiya, M., Lawson, H. W., Chesson, H., Unger, E. R., et al. (2007). Quadrivalent human papillomavirus vaccine: Recommendations of the advisory committee on immunization practices (ACIP) [electronic version]. MMWR Morbidity and Mortality Weekly Report 56(RR02), 1–24.


Marlow, L., Forster, Wardle, J., Waller, J et al (2009). Mothers’ and Adolescents’ Beliefs about Risk Compensation following HPV Vaccination. J Adolesc Health; 44:446-451.


Olshen E., Woods E.R., Austin D.B., et al. (2005). Parental acceptance of the human papillomavirus vaccine. J Adolesc Health; 37:248-251.


Saslow, D., Castle, P. E., Cox, J. T., Davey, D. D., Einstein, M. H., Ferris, D.G., et al. (2007). American Cancer Society guidelines for human papillomavirus (HPV) vaccine use to prevent cervical cancer and its precursors. CA: A Cancer Journal for Clinicians; 57, 7–28.


Smoak, N. D., Scott-Sheldon, L., Johnson, B.T., Carey, M. P. et al. (2006). Sexual Risk Reduction Interventions Do Not Inadvertently Increase the Overall Frequency of Sexual Behavior: A Meta-Analysis of 174 Studies with 116,735 Participants. J Acquir Immune Defic Syndr; 41(3): 374-384.




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