Effect of vaccination against oral HPV-16 infection in high school students in the city of Cali, Colombia.

INTRODUCTION: In recent years, an association between HPV-16 and oropharyngeal cancers has been reported. Therefore, it is necessary to evaluate whether vaccination decreases the exposure of HPV-16 in the oral cavity. OBJECTIVE: To evaluate the effect of vaccination on oral HPV-16 infection in high school students in the city of Cali, Colombia. METHODS: In this cross-sectional study, HPV-16 DNA was detected in samples from the oral cavity and throat of 1,784 high school students of both genders, aged 14-17 years old, in 21 schools in the city of Cali, Colombia. The number in vaccinated girls were 944 vs., 95 unvaccinated girls and 745 unvaccinated boys. RESULTS: The HPV exposure percentages were: 0.7% in vaccinated girls, 3.2% in unvaccinated girls and 2.3% in unvaccinated boys. The odds ratio (OR) of detection of HPV-16 in vaccinated versus unvaccinated students was 0.28 (95% CI: 0.07-0.88), representing a 72% reduction in HPV-16 detection in students immunized with two doses. The odds of detection of HPV-16 in unvaccinated male students were 3.6 times those of vaccinated girls (OR = 3.6, 95% CI: 1.21-12.81) and increased to almost eight-fold in boys who had initiated sexual activity (OR = 7.74, 95% CI: 1.53-75.09). CONCLUSIONS: HPV vaccination was associated with the reduction of HPV-16 exposure percentages in the oral and oropharyngeal cavity.