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

TL;DR

This study examines HPV types in cervical cancer cases in The Gambia to establish a baseline before vaccine implementation.

Contribution

The study provides baseline HPV genotype distribution data in The Gambia to inform future vaccine policy evaluation.

Findings

HPV 16 was the most common genotype in cervical cancer cases in The Gambia.

Multiple HPV infections involving HPV 16 and/or 18 were detected in 14 cases.

The nonavalent HPV vaccine may be more beneficial than the quadrivalent vaccine in The Gambia.

Abstract

Cervical cancer is the leading cause of cancer deaths in Gambian 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 study aims 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.

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 human β-globin gene was amplified in 119 samples, which were subsequently tested for HPV DNA.

HPV was prevalent in 87.4% (104 of 119) cervical cancer cases, 12.6% (15/119) samples tested negative. Amongst cervical cancer cases, HPV 16 genotype was the most frequent type accounting for 53.8% (56 /104), followed by other HR-HPV genotypes 17.3% (18/104), and HPV genotype 18 was 15.4% (16/104). Furthermore, multiple HPV infections involving HPV 16 and /or 18 was detected in 14 cases as follows: HPV genotypes 16 and 18 (3.8%, 4 /104), HPV 16 and other HR-HPV (6.7%, 8/104), and HPV 18 and other HR-HPV (1.9%, 2/104). A significant association between age and diagnosis with cervical cancer (p = 0.02), and HPV genotype 16 (p = 0.04) was observed.

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 cervical cancer cases with other HR-HPV, and combined infections of HPV 16 with 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.

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