Human papillomavirus type-specific distribution in cervical intraepithelial neoplasia and cancer in The Gambia prior to HPV immunization programme: A baseline for monitoring the quadrivalent vaccine

Background: Persistent infection with the high-risk human papillomavirus (HR-HPV) is associated with causing nearly 95% of cervical cancer and remains a worldwide concern. In the Gambia, cervical cancer is the leading cause of cancer deaths in women. Current estimates indicate that 286 women are annually diagnosed with cervical cancer with a fatality rate of 70%. In an attempt to address this, in 2019 the quadrivalent HPV vaccine was incorporated into the Gambia’s expanded programme on Immunisation. The aim of the study was to retrospectively assess the prevalence and distribution of high-risk HPV genotype in archived, formalin fixed paraffin embedded cervical biopsy tissues diagnosed with cervical cancer in the Gambia from year 2013 -2022. Method: A total of 223 samples with histologically diagnosis of cervical cancer with adequate tissues were sectioned and deparaffinised, followed by HPV DNA extraction and the detection of HR-HPV by real-time multiplex PCR. The internal housekeeping gene was amplified in 119 samples, which were subsequently tested for HPV DNA. Results: HPV prevalence was found to be 87% (104 /119) in cervical cancer cases, 15 (12.6%) samples tested negative for HPV DNA. In single infections, HPV 16 genotype was the most frequent type in cervical cancer cases accounting for 53% (56/104), followed by other high risk HPV genotypes 17% (18/104), and HPV genotype 18 was found in 15% (16/104) of cervical cancer cases. HPV related cervical cancer was most common in the 32 -42 year (28.8%, 30/104) aged women. A significant association between age and diagnosis with cervical cancer (p = 0.023), and HPV genotype (p = 0.038) was observed. Conclusion: There was no difference in the distribution of HPV 16 and 18 genotypes in cervical cancer cases in The Gambia in comparison with the global distribution. However, the high prevalence of single infections with other HR-HPV, and multiple infections with HPV 16 and other HR-HPV genotypes seen in this study, clearly shows that the nonavalent HPV vaccine could be more beneficial for The Gambia. This study provides The Gambia with a baseline data to use in policy decisions regarding future evaluation of the quadrivalent HPV vaccine in the country.