Associations between high-risk human papillomavirus genotypes: evidence of HPV16 predominance as a monoinfection and its no stronger link with high-grade lesions

BACKGROUND: High-risk human papillomaviruses (HR-HPVs) are the main etiological agents of cervical cancer. Although coinfections with multiple HPV types are common, it remains unclear whether certain genotypes tend to associate preferentially or whether these associations occur randomly. In particular, HPV16 is considered the most oncogenic type, but its behavior in the context of mono- versus coinfection is less well defined. METHODS: We retrospectively analyzed cervical cytology and HPV genotyping results from 1,140 women aged 25-65 years. We calculated absolute and relative frequencies of individual HR-HPV types, examined between associations of two-type coinfections, and compared observed versus expected frequencies to assess whether genotype combinations occurred beyond chance. Special attention was given to HPV16, analyzing cytological outcomes in monoinfections versus coinfections. RESULTS: Most HR-HPV coinfections occurred at frequencies consistent with chance, suggesting no preferential interactions between genotypes. HPV16, however, was disproportionately present as a monoinfection. Importantly, no HPV16 monoinfections were significantly more associated with high-grade squamous intraepithelial lesions (HSIL) than HPV16 coinfections (p=0,365). CONCLUSIONS: HPV16 was the most frequent genotype and was more commonly observed as a monoinfection than several other HR-HPV types. However, HPV16 monoinfections were not significantly associated with a higher frequency of HSIL compared with HPV16 coinfections. The observed genotype distribution patterns should be interpreted cautiously within the epidemiological context of opportunistic prevaccination screening.