High rate of non-vaccine-targeted high-risk HPV genotypes in Ethiopia: Its implication in future vaccine selection

Abstract

Abstract Since the distribution of high-risk HPV genotypes varies across countries, genotype-based vaccination is widely recommended to control the burden of cervical cancer. As of 2018, HPV vaccination program is underway in Ethiopia for girls aged 9–14 years against HPV-6, HPV-11, HPV-16 and HPV-18. However, the rate and distribution of non-vaccine-targeted genotypes are not well characterized. Therefore, by determining the prevalence and characterizing their genotypes, we assessed the level of multiple infections with other vaccine-targeted genotypes in Ethiopia. A health facility-based cross-sectional study including 110 women with a positive HPV DNA results was conducted from April to August 2021. We used a structured questionnaire to collect demographic and clinical data and collected cervical swabs using L-shaped FLOQSwabs®. We, then, stored them in eNAT nucleic acid preservation and transport® medium. Women's cytological profile was determined based on Pap smear teat results, and we made automated nucleic acid extraction using STARMag 96 ProPrep Universal Extraction Kit. We have used a real-time amplification assay to amplify and identify the HPV Late 1 [L1] gene used for genotyping. After the collected data has entered into Epi data version 3.1 software, the analysis was done with STATA version 14. Among 901 women who underwent HPV DNA testing, only 110 women [age range 30 to 60 years, mean age = 36.5 years and SD ± 6.9] had positive HPV DNA results and were included in the study. Among these, 108 women had valid co-testing [Pap test and HPV DNA test] results for further analysis, and the results of the remaining 2 women were rejected. Overall, the prevalence of non-vaccine-targeted HPV was 51.8% (95% CI: 0.424–0.611), of which 28 women (25.4%, 95% CI: 0.181–0.345) had a single non-vaccine HPV genotype infection. The remaining 29 women (26.4%, 95% CI: 0.190–0.355) experienced multiple infections. The non-vaccine-targeted genotypes of HPV-35 (10%, 95% CI: 0.056–0.173), HPV-68 (8.2%, 95% CI: 0.043–0.151), HPV-56 (7.3%, 95% CI: 0.036–0.140), and HPV-66 (7.3%, 95% CI: 0.036–0.140) were found in higher numbers. In addition, out of these 108 women, 93 (86.1%, 95% CI: 0.781–0.915) had low-grade squamous intraepithelial lesions, 13 (12%, 95%CI: 0.071–0.198) no intraepithelial lesion or malignancy, and two (1.9%, 95%CI: 0.004–0 .072) high-grade squamous intraepithelial lesions. Furthermore, there was no statistical difference (p = 0.755) between vaccine-targeted and non-vaccine-targeted genotypes as the primary cause of cervical injury. In Ethiopia, non-vaccine-targeted HPV genotypes are highly prevalent, including HPV-35, HPV-68, HPV-56, and HPV-68. More than a quarter of women had multiple infections, which increase their risk of developing cervical cancer. Therefore, changing from the current vaccine that protects against four HPV types to the vaccine that covers seven HPV genotypes will have better outcome in preventing cervical cancer.