Prevalence of cervical infection with HPV type 16 and 18 in Vietnam: implications for vaccine campaign.

ABSTRACT

BACKGROUND: The Expanded Program on Immunization currently considers offering Human Papilomavirus vaccine on a routine basis in Vietnam. However, as the current available vaccine can prevent only two types HPV 16 and 18, before implementing a large-scale vaccine campaign we need information about the prevalence of infection with only HPV 16 and 18 in Viet Nam. This study was done in 5 large cities in Vietnam to estimate the prevalence of HPV 16 and/or 18 infections and to explore the distribution of other high risk types of HPV among married women in these provinces. METHODS: The study employed a cross-sectional design with multistage sampling. The sample size included 4500 married women in two rounds (aged ranged from 18-69 years old, median age 40 year old). Participant were randomly selected, interviewed and given gynaecological examinations. HPV infection status (by real-time PCR kit using TaqMan probe) and HPV genotyping test (by Reverse dot blot) were done for all participants. RESULTS: The prevalence of cervical infection with HPV type 16 and/or 18 among married women in this study ranged from 3.1% to 7.4%. Many positive HPV cases (ranged from 24.5% to 56.8%) were infected with other type of high risk HPV which can lead to cervical cancer and cannot prevented by currently available vaccines. In addition to HPV 16 and/or 18, most common types of high risk HPV were types 58, 52, 35 and 45. Awareness about HPV and HPV vaccines was still low in the study samples. DISCUSSION: While it is relevant to implement an HPV vaccine campaign in Viet Nam, it is important to note that one can be infected with multiple types of HPV. Vaccination does not protected against all type of high risk HPV types. Future vaccine campaigns should openly disclose this information to women receiving vaccines. CONCLUSION: High prevalence of infection with HPV high risk types was observed in this study. As HPV infection has a high correlation with cervical cancer, this study emphasizes the need for both primary prevention of cervical cancer with HPV vaccines as well as secondary prevention with screening.