Prevalence of high-risk human papillomavirus type 16/18 infection among women with normal cytology: risk factor analysis and implications for screening and prophylaxis

Objective: To determine the prevalence of high-risk human papillomavirus (HR-HPV) 16/18 infection of uterine cervix among women in the reproductive age group, with cytologically normal cervical (Pap) smears; to analyse the risk factors for HR-HPV acquisition and to address their implications for cervical cancer screening and prophylaxis in a low resource setting. Methods: Cervical samples from 769 cytologically negative women (age 18-45 years) attending a tertiary care centre in Delhi were subjected to HPV DNA testing and HR-HPV 16/18 and low-risk (LR)-HPV 6/11 sub-typing by polymerase chain reaction. Univariate risk factor analysis was carried out in HR-HPV positive (n = 86) versus HR-HPV negative women (n = 683) by chi-square test. Results: The overall HPV prevalence among cytologically normal women was 16.6%. HR-HPV16 was detected in 10.1%, whereas HPV18 was detected in 1% of women. HR-HPV 16/18 comprised 67% of the total HPV positives. There was no decline in HR-HPV positivity with age, and women aged 40-44 years were at significantly increased risk for HR-HPV prevalence (P = 0.03). Statistically significant associations of HR-HPV infection were found with risk factors such as high parity (P = 0.04), cervicitis/hypertrophic cervix (P = 0.01), unhealthy cervix (P = 0.04), rural residence (P = 0.03), low socioeconomic status (P = 0.01) and illiteracy (P = 0.07). Conclusions: Although the sample size was small, based on the observation that HR-HPV 16 and 18 contributed significantly to the overall HPV prevalence in our setting, we speculate that testing/prophylaxis for these prevalent high-risk types could perhaps make cervical cancer screening and preventive programmes cost-effective. Larger community-based studies on HPV prevalence and persistence are required to validate these findings before definitive recommendations can be made to the policy makers.