HPV Vaccination in Special Risk Groups: 5 Year Follow-up

Overview

In 2007-2009 the investigators conducted a study to determine the immunogenicity response to HPV vaccine in special risk patients known to be at increased risk of abnormal cervical cytology. The serological response to the vaccine was measured 1 month post the third and final dose (n=70) finding a robust response overall. The aim of this follow-on study is to provide data on the long-term protection offered by the HPV vaccination. The persistence of antibody 5 years post immunisation is unknown and the impact on cervical cytology abnormalities in these special risk groups is important. The study results will help inform national immunisation program recommendations re- booster HPV vaccine doses.

This study is an open interventional study based at two paediatric tertiary centres in Melbourne, Australia. It is specifically looking at the long term immunogenic response to the 4 valent HPV vaccine (4vHPV) Gardasil in paediatric rheumatology disease (PRD) and Irritable bowel disease (IBD) in participants who complete the primary HPV immunological study. The study participant's response to the vaccine will be compared to Merck historical age-matched controls as there is currently no serological correlate of protection for the HPV vaccine. The participants have already received the vaccine as part of the Australian federally funded catch up program which will run until mid-2009. All participants are part of 'Special risk groups'; which as defined by the Australian Immunisation Handbook, as patients who may have: 1. special vaccination needs (e.g. children/ adolescents with a chronic medical condition) ; or 2. a suboptimal response to vaccination (e.g. due to impaired immunity); or 3. an increased risk of adverse events following immunization (AEFI) The 'special risk groups' currently included in the study are: 1. PRD- Paediatric Rheumatological Diseases 2. IBD- Inflammatory Bowel Disease Number of participants Total number of patients to be recruited is N = 60 The aim is to recruit n= 45 patients from PRD and n=15 patients from IBD. Immunisation history will be correlated with the HPV register. Main outcome measures The primary immunogenicity endpoint will be serum antibody by month 60 (i.e. 5 years post 3rd and final dose of 4vHPV vaccine). Antibody titres are determined by using type-specific competitive neutralising antibody to epitopes on virus like particles (VLP). This will be for each of the 4 serotypes in the vaccine \[6,11,16,18\], with geometric mean titre (GMT) will be measured in mMU; and will be compared with GMT from historical age-matched controls. Frequency of assessment There will only be one immunogenicity assessment point, 60 month post the third and final dose of 4vHPV vaccine. Primary Objective: • Long term immunogenicity of the quadrivalent 4/6/11/18 HPV vaccine Gardasil® by following up a cohort of adolescent females aged 16-30 years with PRD or IBD, 5 years post HPV vaccination at the Royal Children's Hospital (RCH) Melbourne. Antibody titres are determined by using type specific neutralizing antibody.The geometric mean titre (GMT) will be measured in mMU; with a type specific cutoff for the assay (\> 20mMU/ml for the HPV6; \> 16mMU/ml for the HPV11; \> 20mMU/ml for the HPV16 and \>24mMU/ml for the HPV18). \[13,15\] HPV serology will be performed using competitive Luminex based immunoassays. Secondary Objective: • The safety of the HPV vaccine in the 2 (PRD, IBD) study groups, measured by the number of adverse events reported by study participants.