Understanding the Immune Response to Meningitis Vaccines

Meningitis Clinical Trial

Official title: Single Centre Open-Label Randomised Trial of Meningococcal Serogroup ACYW-135 B Cell Response to Primary & Booster Doses of ACWY Conjugate Vaccine & Primary Dose of ACWY Polysaccharide With Booster Dose of ACWY Conjugate in Adults

Status Completed

Clinical Trial Summary

The purpose of the study is to evaluate and compare the immune response to two vaccines against 4 related bacteria: meningococcal serogroups A, C, W−135 and Y. These bacteria can cause meningitis and /or septicaemia (blood poisoning). The two vaccines are a protein−polysaccharide conjugate vaccine (MenACWY)and a meningococcal plain polysaccharide vaccine(MenACWY PS). Both vaccines are licensed and are currently used for travellers to areas with a high incidence of invasive meningococcal disease. However, plain polysaccharide vaccines are known to be poorly immunogenic in children and they do not stimulate immunological memory, apart from the serogroup A component. In contrast, a protein-polysaccharide conjugate vaccine against meningococcal serogroups A, C, W−135 and Y has been found to be immunogenic in infants and to be able to induce immunological memory.

The proposed study is a single centre, open−label, randomised, controlled study in 150 healthy adults aged 18−70 years. The participants will be given either 2 injections of the meningococcal protein−polysaccharide conjugate vaccine one month apart, or one injection of the meningococcal plain polysaccharide vaccine followed one month later with an injection of the meningococcal conjugate vaccine. Blood samples will be collected before immunisation and at several time points following immunisations to evaluate the level of meningococcal specific antibody induced by two different vaccination regimes. The data derived from the study will be relevant in determining which of these vaccines should be used in preference in travellers who are receiving immunisation against meningococcal disease before travelling to high risk areas. Additionally, a number of scientific questions regarding the nature of the immune response to the two vaccines (specifically looking at the white blood cells responsible for producing antibodies, known as B cells) and the role of genetic variations in influencing the vaccine recipient's immune response will be addressed in the study.

Clinical Trial Description

In this single centre, open−label, randomised, controlled study of 150 healthy adults aged 18−70 years we will be evaluating the immune response to immunisation with 2 different vaccines against 4 related bacteria known as Neisseria meningitidis serogroups A, C, W−135 and Y. These bacteria (also known as meningococci) can produce meningitis and septicaemia (blood poisoning). The first vaccine, which has been used as a travel vaccine in the UK for several years, is known as the MenACWY plain polysaccharide (MenACWY PS). The other vaccine, known as the MenACWY conjugate vaccine (MenACWY) was licensed in the UK in March 2010 and is now recommended as a travel vaccine by the Department of Health.

In order to evaluate the immune response to these vaccines we will be measuring not only the blood levels of antibodies specific to serogroup A, C, W−135 and Y meningococci, but also the population of white blood cells known as B cells which produce these antibodies. Two forms of these B cells will be measured, the plasma cells (which actively produce antibodies) and memory B cells (which do not produce antibodies but persist in the body and can be stimulated to turn into plasma cells when required).

Participants will be randomised into group I or group II on a 1:1 basis to receive either MenACWY or MenACWY PS. One month later, all participants will receive a booster dose of the MenACWY conjugate vaccine. The ACWY polysaccharide vaccine will be administered subcutaneously, and the MenACWY conjugate vaccine will be given intramuscularly. Each participant will be observed for at least 15 minutes after vaccination for any immediate reactions.

Blood samples will be collected from each participant for analysis prior to each immunisation, 7 days following the first immunisation and 7 and 28 days following the second immunisation. The volume of blood samples obtained at each timepoint will be 20 mLs. Blood will be used for antibody analysis (by ELISA), B cell analysis (by ELISpot)and DNA extraction for genetic analysis.

In summary, participants enrolled in this study will have a total of 5 visits in a period of 2 months. They will receive two doses of the MenACWY conjugate vaccine or one dose of the ACWY polysaccharide vaccine followed by one dose of the MenACWY conjugate vaccine. During this period they will have a total of 5 blood samples taken (5x20mL= 100 mL of blood taken in a 2 month period). ;

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Open Label, Primary Purpose: Prevention

Related Conditions & MeSH terms

• Meningitis
• Septicemia

• NCT number: NCT00901940
• Study type: Interventional
• Source: University of Oxford
• Status: Completed
• Phase: Phase 3
• Start date: June 2009
• Completion date: October 2010