Does HPV-18 co-infection increase the risk of cervical pathology in individuals with HPV-16?

We aimed to investigate differences between HPV-16 mono- and HPV-16/18 co-infections in terms of cervical dysplasia and invasive cancer.

This multicentre, retrospective study spanned from December 2017 to December 2020, involving women who visited gynaecological oncology clinics for colposcopy with either HPV-16 or HPV-16/18 positivity. A total of 736 patients, 670 in Group 1 (HPV-16 positivity) and 66 in Group 2 (HPV-16/18 positivity), were compared for the presence of CIN2+ lesions detected by colposcopic biopsy or endocervical curettage (ECC). Exclusions included hysterectomized patients, those with prior gynaecological cancers, and patients with HPV positivity other than types 16 and 18.

Among the included patients, 42.4% had a diagnosis of CIN2+ lesions. The cytology results demonstrated abnormal findings in 45.3% in Group 1 and 42.2% in Group 2, with no significant difference between the groups. ECC revealed CIN2+ lesion in 49 (8.7%) patients in group 1, while only 1 (1.7%) patient had CIN2+ lesion in group 2. There was no difference between 2 groups in terms of ECC result (p = 0.052). In group 1, 289 (43.1%) patients had CIN2+ lesion, while 23 (34.8%) patients had CIN2+ lesions in group 2. There was no difference between group 1 and 2 in terms of diagnosis of CIN2+ lesions (p = 0.19).

This multicentre retrospective study found no significant differences between HPV-16 mono- and HPV-16/18 co-infections regarding cervical pathologies. Larger studies are needed to validate and further explore these findings.