Repeated detection of vaccine-preventable anal HPV genotypes in a screened cohort: a retrospective observational study

The clinical relevance of concurrent vaccine-preventable anal HPV genotype infections, particularly for short-term repeated detection and cytologic outcomes in screened high-risk populations, remains uncertain. We performed a single-centre retrospective study of 145 adults with at least one 9-valent vaccine-preventable anal HPV genotype at baseline and repeat HPV DNA testing and cytology approximately 12 months later. Baseline infections were classified as single- or multiple-genotype infections. Outcomes included clearance of all baseline vaccine-preventable genotypes, genotype-specific repeated detection, detection of new vaccine-preventable genotypes, complete HPV negativity, and cytologic regression or progression. At baseline, 70 participants (48.3%) had single and 75 (51.7%) had multiple genotype infections; most were male (95.2%) and people living with HIV (88.3%), reflecting a highly selected anal HPV-screened cohort. Multiple infections were associated with more frequent abnormal baseline cytology (69.3% vs. 45.7%). At follow-up, clearance of all baseline vaccine-preventable genotypes was more common after single than multiple infections (34.3% vs. 12.0%). Complete HPV negativity was also more frequent after single infection (24.3% vs. 4.0%), although this stringent endpoint is intrinsically more difficult to achieve in individuals with multiple baseline infections. New vaccine-preventable genotype detection did not differ significantly between groups. Genotype-specific repeated detection was generally similar between groups, except for HPV58, a finding based on small subgroup numbers. Cytologic regression was more frequent after single infection, but not statistically significant. Multiple vaccine-preventable anal HPV genotype infections were associated with greater baseline cytologic abnormality and lower clearance of baseline vaccine-preventable genotypes at 12 months. Given the retrospective design, selected population, limited event counts, and residual confounding, these findings should be interpreted as hypothesis-generating and do not prove impaired biological clearance.