Background: Female patients receiving immunosuppressive therapy may be at increased risk for human papillomavirus (HPV) infection and cervical neoplasia.
Methods: We administered the 3-dose HPV vaccine Gardasil to 37 females aged 9 to 26 years with inflammatory bowel disease (IBD) prescribed immunosuppressive therapy (prospective cohort). Geometric mean titers (GMT) in milli-Merck (mMu/mL) units were determined before dose 1 and 1 month after dose 3 by competitive Luminex immunoassay (cLIA) and qualitatively compared with healthy females of similar age from Merck's database. Side effects and adverse events were evaluated. Concurrently, in 15 similar patients with inflammatory bowel disease previously vaccinated by their primary care provider, we assessed antibody titers by competitive Luminex immunoassay and total immunoglobulin G LIA after dose 3 of vaccine (range, 0.5-27 months).
Results: Mean age of prospective patients was 15 years with 51% on anti-tumor necrosis factor therapy and 49% on immunomodulators: 33 of 37 completed all 3 doses. Seropositivity after dose 3 was 100% for types 6, 11 and 16 and 96% for type 18. Geometric mean titers for HPV-6, HPV-11, HPV-16 and HPV-18 was 1080, 1682, 3975 and 858, respectively and did not qualitatively differ from healthy females. No serious adverse events were attributable to the vaccine. In the previously vaccinated cohort, seropositivity was 100% for types 6, 11, and 16, and 40% for type 18 by competitive Luminex immunoassay (93% for HPV-18 by immunoglobulin G LIA). Titers decreased with time since dose 3.
Conclusions: In this small study of patients with inflammatory bowel disease prescribed immunosuppressive therapy, Gardasil was immunogenic and there were no clinically significant vaccine-associated adverse events.