A meta-analysis of human papillomavirus type-distribution in women from South Asia: implications for vaccination

To determine human papillomavirus (HPV) prevalence and type-distribution in women from South Asia, with and without cervical lesions, in order to estimate the impact of an HPV 16/18 prophylactic vaccine in this region and to assess additional types that should be incorporated in new vaccines.

A meta-analysis was conducted that included studies using polymerase chain reaction to detect HPV-16, -18, -6, -11 and at least one other HPV type, with a minimum of 20 cases in each grade of lesion. Total as well as type-specific prevalence of various HPV types were estimated, stratified by cervical lesion grade, using Stata 9.0 software package.

Nine studies from India fulfilled the inclusion criteria. A total of 558, 52, 52 and 3061 women, respectively with invasive cervical cancer (ICC), high-grade squamous intraepithelial lesions (HSIL), low-grade squamous intraepithelial lesions (LSIL) and normal cytology/histology were included. Overall HPV prevalence was 94.6%, 86.5%, 65.4% and 12.0% in women with ICC, HSIL, LSIL and normal cytology/histology, respectively. In ICC, HPV-16 was the predominant type (64.8%), followed by HPV-18, -45, -33, -35, -58, -59 and -31. The estimated HPV-16/18 positive fraction was 78.9% in women with ICC (87.7% in North and 77.2% in South India), 61.5% with HSIL, 30.8% with LSIL and 3.9% in women with normal cytology/histology. There was no difference in overall HPV prevalence in cervical cancer between North and South India (P=0.063). However, HPV-16 and -45 appeared to be more prevalent in North India (P=0.018 and 0.013, respectively), while HPV-35 appeared to be more prevalent in South India (P=0.033).

It is estimated that HPV-16/18 vaccines will provide over 75% protection against ICC in South Asia. HPV-45, -33, -35 and -58 account for an additional 20% of cervical cancer in this region. The addition of these additional HPV types in a second-generation vaccine could provide optimal cervical cancer prevention in this region.