Immunogenicity and Duration of Immunity in Immunosuppressed Children Vaccinated With Quadrivalent HPV Vaccine

To determine the immunogenicity, safety and persistence of immunity following human papillomavirus (HPV) vaccination in three groups of immunosuppressed children: recipients of allogenic bone marrow transplant, recipients of renal and liver transplants, and patients with juvenile chronic arthritis, inflammatory bowel disease and other autoimmune conditions who are on longterm immunosuppressive therapy.

Significance: Immunosuppressed populations are diverse in terms of degree, type and duration of immunosuppression. The study compares several groups in order to address the heterogeneity of immunosuppression and how this affects vaccine response. BMT patients have extreme, severe immunosuppression in the short term, but recover immune function with time. In contrast, solid organ transplant recipients have ongoing, chronic immunosuppression. Although successful cessation of immunosuppressives in liver transplant patients has been reported, most patients require ongoing treatment. The inflammatory bowel disease group of patients represents a non-transplant group who require ongoing, often low level immunosuppression, often with corticosteroids. Our study will compare these three groups, followed up for five years for duration of immunity. Time of vaccines, time of serological measures of immune response are as follows.

Serum collections:

0 - Baseline (before HPV vaccine dose 1); 2 months - At the time of receipt of HPV vaccine dose 2 (to measure response to dose 1); 6 months - At the time of receipt of HPV vaccine dose 3 (to measure response to dose 2); 7 months - 1 month after HPV vaccine dose 3; 12 months - after HPV vaccine dose 1; 2 years after HPV vaccine dose 1; 3 years after HPV vaccine dose 1; 4 years after HPV vaccine dose 1; 5 years after HPV vaccine dose 1.