Dynamic models of pneumococcal carriage and the impact of the Heptavalent Pneumococcal Conjugate Vaccine on invasive pneumococcal disease

BMC Infectious Diseases

Research Article

Yoon Hong Choi¹  Elizabeth Miller¹  Robert George¹  W John Edmunds²  Nigel J Gay³  Alessia Melegaro³ 

[1] Centre for Infections, Health Protection Agency, 61 Colindale Avenue, NW9 5EQ, London, UK;Centre for Infections, Health Protection Agency, 61 Colindale Avenue, NW9 5EQ, London, UK;Infectious Disease Epidemiology Unit, London School of Hygiene and Tropical Medicine, Keppel Street, London, UK;DONDENA Centre for Research on Social Dynamics, Bocconi University, Via Guglielmo Rontgen, Milan, Italy;Centre for Infections, Health Protection Agency, 61 Colindale Avenue, NW9 5EQ, London, UK;

关键词: Acute Otitis Medium;    Invasive Pneumococcal Disease;    Pneumococcal Serotypes;    Pneumococcal Carriage;    PCV7 Vaccination;   

DOI  :  10.1186/1471-2334-10-90

 received in 2009-09-09, accepted in 2010-04-08,  发布年份 2010

来源: Springer

【 摘 要 】

BackgroundThe 7-valent pneumococcal conjugate vaccine has been introduced in national immunisation programmes of most industrialised countries and recently in two African GAVI eligible countries (Rwanda and The Gambia). However the long term effects of PCV are still unclear, as beneficial direct and herd immunity effects might be countered by serotype replacement.MethodA dynamic, age-structured, compartmental model of Streptococcus pneumoniae transmission was developed to predict the potential impact of PCV7 on the incidence of invasive disease accounting for both herd immunity and serotype replacement effects. The model was parameterised using epidemiological data from England and Wales and pre and post-vaccination surveillance data from the US.ResultsModel projections showed that serotype replacement plays a crucial role in determining the overall effect of a PCV7 vaccination programme and could reduce, negate or outweigh its beneficial impact. However, using the estimate of the competition parameter derived from the US post-vaccination experience, an infant vaccination programme would prevent 39,000 IPD cases in the 20 years after PCV7 introduction in the UK. Adding a catch-up campaign for under 2 or under 5 year olds would provide a further reduction of 1,200 or 3,300 IPD cases respectively, mostly in the first few years of the programme.ConclusionsThis analysis suggests that a PCV vaccination programme would eradicate vaccine serotypes from circulation. However, the increase in carriage of non-vaccine serotypes, and the consequent increase in invasive disease, could reduce, negate or outweigh the benefit. These results are sensitive to changes in the protective effect of the vaccine, and, most importantly, to the level of competition between vaccine and non-vaccine types. The techniques developed here can be used to assess the introduction of vaccination programmes in developing countries and provide the basis for cost-effectiveness analyses.

【 授权许可】

Unknown   
© Melegaro et al; licensee BioMed Central Ltd. 2010. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.