Impact of HPV Vaccination on Juvenile Laryngeal Papillomas and Conjunctival Papillomas in Denmark: Incidence and Analysis of HPV Subtypes in Relation to Vaccination.

Papillomas, predominantly caused by low-risk Human papillomavirus (HPV), can affect the respiratory tract and conjunctiva. This nationwide Danish registry study assesses the HPV vaccination programme's effectiveness in preventing juvenile laryngeal and conjunctival papillomas. Incidence rates were calculated using national registry data from 2005/2008 to 2024. In the Danish Pathology Registry, 33 juvenile laryngeal and 134 conjunctival papilloma patients were identified using SNOMED codes. HPV subtyping was performed in-house for laryngeal biopsies lacking prior data, yielding results for 27 patients. HPV-6 or -11 was identified in 74.1% of cases. Vaccination status was retrieved for conjunctival patients and for mothers of laryngeal patients. The incidence rate of juvenile laryngeal papillomas was 0.190 per 100,000 (2005-2013) and 0.107 (2014-2024) (p = 0.145). No mothers of laryngeal patients had received HPV vaccination before delivery. Conjunctival papilloma incidence declined from 2008 to 2024, with an annual percent change of -5.3% (p = 0.002). A total of 22 conjunctival patients were vaccinated before first biopsy, with a median interval of 5 years and 8 months between first dose and biopsy. In Denmark, juvenile laryngeal papilloma incidence remained low and occurred only in children of unvaccinated mothers, while conjunctival papillomas showed a significant decline consistent with a protective effect of the HPV vaccination programme.