Some commentators have expressed concern that young women who have been vaccinated against the human papillomavirus (HPV) may engage in riskier sexual behaviors than they would have had they not received the vaccine. However, in a recent study, most young women who had been vaccinated at an urban clinic reported that despite the biological protection conferred by the vaccine, they still felt a strong need to practice safer sex.¹ On a 10-point scale, half of vaccinated participants rated their need to practice safer sex as 9 or higher; only 4% rated that need as 5 or lower. Young women’s perceived need to practice safer sex was inversely related to their level of knowledge about HPV and the HPV vaccine.

Study participants were recruited at an urban, hospital-based primary care office to take part in a 30-month study examining attitudinal and behavioral changes among young women receiving an HPV vaccine. To enroll, young women had to be 13–21 years old, be willing to take part in a longitudinal study and have received the first of three HPV vaccination inoculations within the past two days. Mothers and female guardians of enrolled young women were also invited to participate.

The current analysis was based on surveys that young women and mothers completed at study entry in 2008–2010. In addition to providing information on their demographic characteristics, young women answered questions regarding their sexual activity, contraceptive use, knowledge about HPV and the vaccine, and sources of information. Additional questions were used to construct three 10-point scales that assessed young women’s postvaccination perceptions regarding their risk of contracting HPV, their risk of contracting other STDs and their need to practice safer sex; higher scores represented greater perceived risk or need for safer sexual behaviors. Mothers’ questionnaires included questions about their demographic characteristics, knowledge of HPV and the HPV vaccine, sources of information and communication with their daughter. In addition to compiling descriptive statistics, the researchers performed logistic regression analyses to identify associations between participant characteristics and young women’s perceived need for safer sexual behaviors.

Overall, 339 young women enrolled in the study. On average, the young women were 17 years old; most were black (76%) and had health insurance (84%). Among the 58% who were sexually experienced, more than half had ever had an STD (54%) or had used a condom at last sex (59%). The full sample’s average score on the HPV and HPV vaccine knowledge scale was 5.3 out a possible 13, and mean scores on the three 10-point outcome scales were 5.0 for perceived HPV risk, 6.1 for perceived risk of other STDs and 8.5 for perceived need for safer sexual behaviors. Half of the young women rated their need to practice safer sex as 9 or higher; only 4% had a mean scale score lower than 5.

The 235 participating mothers were, on average, 41 years old; substantial minorities had had an abnormal Pap test (41%) or an STD (43%). Their mean score on the HPV and HPV vaccine knowledge scale was 6.9.

In multivariate analyses, several of young women’s characteristics were associated with perceived need to practice safer sex. Vaccine recipients perceived less need for safer sex if they were less knowledgeable about HPV and the HPV vaccine (odds ratio, 1.3 per additional incorrect answer), were less concerned about becoming infected with the virus (1.9 per one-point decrease in concern score), had never used alcohol (1.8) or had learned about HPV from a teacher (2.3). In addition, sexually experienced respondents were more likely to feel a lower need for safer sex if they had not used a condom the last time they had had sex with their main partner (3.5).

In an analysis restricted to young women whose mothers were participating in the study, three maternal characteristics were associated with daughters’ perceiving less need for safer sex: lower maternal HPV and HPV vaccine knowledge scores (odds ratio, 1.2 per incorrect answer), mothers’ having received HPV vaccine information from a physician (3.1) and mothers’ having not talked with their daughter about the vaccine (2.1).

Finally, a third multivariate analysis, again restricted to the 235 mother-daughter dyads, assessed both young women’s and mothers’ characteristics. Five were associated with elevated odds that young women would report less need for safer sex: lower levels of HPV knowledge among daughters (odds ratio, 1.2 per incorrect answer) or among mothers (1.2 per incorrect answer), lower levels of concern about HPV infection among daughters (1.8 per one-point decrease), lack of communication about the vaccine between mother and daughter (2.2) and mothers’ having learned about the vaccine from a physician (2.5).

The researchers note a number of study limitations. The findings may not be generalizable to other populations, and responses may have been influenced by social desirability bias. Moreover, vaccine recipients’ risk perceptions may change over time and may not reflect their sexual behavior. Still, the investigators note that the results suggest that most young women "continue to perceive the importance of safer sexual behaviors after receipt of the first HPV vaccination." They add, however, that "effective educational interventions about HPV and HPV vaccines may need to be developed for adolescents and their mothers"; the finding that young women felt less of a need to practice safer sex if their mother had learned about HPV from a doctor may indicate that mothers had not adequately understood the information they received or had not accurately conveyed it to their daughters.—P. Doskoch