Impact of the UK pneumococcal conjugate vaccine programme on pneumococcal genetics and disease manifestations.
Dr Bruno Pichon, Dr Mary Slack, Dr Rob George, Prof Liz Miller
- Start Date:
01 January 2006
HPA Centre for Infections, London, UK
The 7-valent pneumococcal conjugate vaccine (PNC-7) will be introduced into the UK infant vaccination programme in 2006. Following the introduction of the vaccine in the US in 2001 the number of Invasive Pneumococcal Disease (IPD) episodes caused by one of the 7 vaccine-preventable serotypes was significantly reduced in both children and adults. However, in the US, significant increases of IPD caused by pneumococci of non- preventable serotype have been observed, including increases of cases of meningitis and of invasive pneumonia. Because of its genetic fluidity, S. pneumoniae has the potential for vaccine evasion and it is anticipated that the positive effects of immunisation with conjugate pneumococcal vaccine effect may well be compromised by serotype replacement and/or capsular switches subsequent to the vaccine introduction.
This project will compare the phenotypic components (serotype, antibiotic resistance profile) and the genetic characteristics of isolates causing IPD providing fundamental data to address questions raised by the immunisation schedule to be used for the UK:
i) Does the PNC-7 vaccine have an effect on the phenotypic and genotypic structure of the pneumococcal population?
ii) If there is an increase in IPD due to non-vaccine serotypes, is this due to emergent genotypes, serotype replacement or capsular switching or a combination of these?
iii) Will pneumococcal meningitis decline in proportion to total IPD or not? If not, what are the characteristics of the pneumococci responsible?
iv) Are particular virulent clones associated with PNC-7 vaccine failures?