Non-Sexual Transmission of Papillomavirus: Is It Part of Our Virome?

BACKGROUND: Human papillomavirus (HPV) has traditionally been considered a sexually transmitted infection, yet accumulating evidence demonstrates that HPV can be acquired through multiple non-sexual routes. Understanding these alternative transmission pathways is critical for interpreting HPV detection in non-sexually active populations and for refining public health strategies. METHODS: This review synthesizes current evidence on non-sexual HPV transmission routes, including vertical (transplacental, intrapartum), perinatal oropharyngeal colonization, fomite contamination, breast milk transmission, and horizontal non-sexual contact. We examine HPV prevalence data from female virgins, neonates, infants, and children, and evaluate metagenomic evidence positioning HPV as a component of the human virome across multiple body sites. RESULTS: Published studies report that vertical transmission occurs in approximately 18.2% of HPV-positive mothers, with neonatal HPV positivity of 3.4% at birth and 100% genotype concordance in transmission pairs. Transplacental transmission has been documented in 10.2% of concordant mother-placenta-newborn triads. Reviewed studies report oropharyngeal colonization at birth reaching 58.2% following vaginal delivery, with 94.3% of colonized neonates clearing infection by 24 months. HPV DNA has been detected on fomites and medical devices, in breast milk (8.6-15%), and across body sites in healthy adults (skin 61.3%, vagina 41.5%, oral cavity 30%, gut 17.3%). Metagenomic studies identify HPV DNA in 68.9% of healthy individuals, with 109 distinct types detected. Female virgins show HPV prevalence ranging from 0-51.1% across studies. CONCLUSIONS: The reviewed evidence suggests that HPV exhibits characteristics of a ubiquitous virome component with multiple non-sexual acquisition routes. These findings have important implications for vaccination strategies, screening interpretation, infection control in healthcare settings, and counseling of pediatric cases and non-sexually active individuals.