Prevalence of oral HPV infection and genotype distribution in Iranian children during the early ages of life.

Abstract

Background: Human Papillomavirus (HPV) infection in the oral cavity has been shown to be common in the young populations with uncertain consequences. Persistent oral oncogenic HPV infection could lead to oropharyngeal malignancy. HPV transmission from mother to fetus is still under question besides the horizontal routes which seem to be emerging. Although HPV infection is mostly transient in young populations, detecting oral HPV in children might be valuable to understand the prevalence, transmission, and natural history of HPV infections in this age group and determination the role of maternal vaccination against HPV. The present study aimed to determine the oral HPV prevalence and genotyping in Iranian children during first-5-year of life for the first time.

Methods: This cross-sectional study was conducted in Pasteur Institute of Iran. Buccal samples of the population ≤ 5 years old and also of a subset of mothers were investigated. DNA extraction was done and Real-Time PCR was performed to characterize HPV infection. The positive samples were re-assessed through hybridization assay.

Results: Totally, 201 children aged from 3 days to 5 years old were enrolled in this study among whom16 children were HPV-positive accounting for 7.9% (n=16) with a higher incidence in the population <1month (27.3%). HPV16 and HPV18 were the most frequent HPV types accounting for 50% and 37.5%, respectively followed by HPV31, HPV35, HPV39 and HPV56. Multiple HPV infections were detected in 7 children among whom HPV16 was dominantly detected (71.4%). In a subgroup of mothers who provided oral samples, the total HPV prevalence was 9.5% and HPV18 was the most frequent type followed by HPV16, HPV82, HPV35 and HPV11. Furthermore, the positive HPV status in mothers led to a significant risk of infection in children (p<0.001; OR=165). HPV genotypes between mothers and offspring did not show full concordance. What is more, a significant difference regarding the type of delivery and HPV positivity in children was observed (p<0.001).

Conclusion: The present research indicates that oral HPV infection is quite common in early ages of Iranian children. Multiple HPV infections and a high prevalence of HPV16 are concerning issues for unknown consequences. Lack of full concordance of HPV types between mothers and offspring highlights the possible routes of horizontal transmission. Detecting oral HPV, especially the oncogenic types, could provide rationales for screening tests and setting policies in the future. Additionally, the obtained results emphasize HPV vaccination programs to reduce the rate of HPV transmission from mothers to children.