PREVIX_COMBOA Randomised Controlled Trial of Pneumococcal Conjugate Vaccines Synflorix and Prevenar13 in Sequence or Alone in High-risk Indigenous Infants (PREV-IX_COMBO): Immunogenicity, Carriage and Otitis Media Outcomes

Aboriginal children in the Northern Territory (NT) have high rates of otitis media caused by non-capsular H. influenzae (NCHi) and pneumococci. Pneumococcal conjugate vaccine has effectively reduced disease caused by the 7 serotypes. Rates of non-vaccine serotype otitis media (OM), particularly 19A is increasing, and NCHi continues to be a major pathogen in perforations. Parallels with pneumonia are highly probable in this population. Vaccines with expanded and early age protection are needed. In early 2009 GSK's pneumococcal H. influenzae protein D conjugate vaccine (PHiD-CV) was licensed in Australia. Compared to the current vaccine, 7PCV, this vaccine offers protection from pneumococcal serotypes 1, 5, 7F as well as NCHi (which is a primary pathogen of OM, and possibly pneumonia). However by 2010, a new generation of Wyeth's 7PCV, PCV13 will also be licensed in Australia. Compared to PHiD-CV this vaccine offers protection from additional serotypes 3, 6A and 19A, however it does not offer protection from NCHi infection. There is no empirical evidence to suggest that either vaccine will have superior clinical efficacy for otitis media or pneumonia in high-risk children. The novel combination strategy proposed for this trial has the potential to provide the best of both vaccines.