Parallel Declines in Human Papillomavirus 6/11-Related Disease Incidences: A National Study of Anogenital Warts and Recurrent Respiratory Papillomatosis in Norway.

Anogenital warts and recurrent respiratory papillomatosis are conditions caused by human papillomavirus (HPV) types 6/11 that can be prevented by vaccination. We analyzed Norwegian national registry data (2010-2023) to assess the impact of the 4-valent HPV vaccine introduced in 2009. Anogenital warts incidence among females aged 15-29 decreased significantly from 1120.0 to 280.6 per 100 000 (annual percentage change: -10.3%), paralleling a sharp decline in recurrent respiratory papillomatosis from 3.7 to 0.6 per 100 000 (annual percentage change: -11.3%). These results strongly support vaccination impact in reducing the burden of HPV 6/11-related diseases, suggesting successful interruption of transmission pathways and substantial population-level protection.