Immunogenicity of HPV Vaccine in Immunosuppressed Children

Overview

Genital HPV is the necessary cause for cervical cancer, as well as a major contributing cause of several other cancers and conditions. There are now effective vaccines against the main oncogenic HPV types, HPV16 and 18. Most research and discussion has focused on targeting the vaccine to young women and older adolescents. Based on this, a national free HPV vaccination program for adolescent girls commenced in 2007, in Australia. However, at the time of commencement, there had been no research on the use of this vaccine in immunosuppressed. Therefore, information on the immunogenicity, safety and duration of efficacy of HPV vaccine when administered to immunosuppressed children is needed. This trial looked at a 3 dose schedule of quadrivalent HPV vaccine in a range of immunosuppressed children, with the endpoint being immunogenicity, followed for 5 years for duration of immunity.

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.