Aims, Scope and Findings of the Global Pertussis Initiative

Publisher Website
Google Scholar
Abstract
Of all the pediatric infectious diseases for which routine vaccination is given, pertussis is the most poorly controlled. Although routine vaccination with either whole cell or acellular vaccines has reduced morbidity and mortality to low levels, deaths still occur in unvaccinated newborns and it appears that adolescents and adults frequently acquire prolonged cough caused by Bordetella pertussis infection. Disease in the older groups indicates that immunity to B. pertussis infection is transient after childhood vaccination, and indeed it is known that even infection with B. pertussis does not give permanent protection against reinfection and disease that perpetuates transmission. The World Health Organization has recognized that pertussis remains a major public health problem1 and estimates that it causes 300,000 deaths worldwide each year. Nevertheless it remains underappreciated by clinicians, particularly those who care for adults. To assess the situation, and to formulate proposals to deal with a persistent problem, in 2001 sanofi pasteur gave an educational grant to a group of 37 experts from 17 countries, allowing them to meet in person and to communicate electronically over a period of several years. The group took the name of “Global Pertussis Initiative (GPI),” and this supplement to The Pediatric Infectious Disease Journal® (with a summary article published elsewhere) contains the fruits of their labors.2 The participants of the GPI collaborated to: assess the extent of, and the underlying reasons for, the ongoing problems with pertussis by evaluating the latest scientific evidence base and exchanging expert opinion on pertussis; appraise pertussis immunization strategies designed to complement or improve current childhood schedules and bring pertussis under control; formulate recommendations on making selected strategies acceptable at country, regional or local levels, and identify urgent research needs; and develop a health economic model to address the cost effectiveness of the selected immunization strategies. In assessing the problems posed by pertussis globally, 3 key areas were addressed: the evolving epidemiology of pertussis; the health and economic burden of pertussis; and the advantages and disadvantages of current treatment and prevention measures. In Section 1 of this supplement, the GPI participants report on the current epidemiologic trends of pertussis globally, the sources of infection and routes of transmission in the vaccination era and the problems surrounding the clinical and laboratory diagnosis of B. pertussis infection. Available data confirm the endemicity of B. pertussis infection but highlight wide discrepancies in pertussis incidence among industrialized nations, reflecting differences in diagnosis, case definitions, surveillance systems, prescribed vaccines, immunization strategies/schedules and herd immunity. Numerous sources note an apparent “resurgence” in reported pertussis disease in highly immunized populations, this being most marked in adolescents and adults. The reasons for these emerging epidemiologic trends are likely to be complex. Factors making their delineation difficult are examined, including: widespread underconsulting, underrecognition and underdiagnosis; heterogeneity in disease expression in older age groups; the unknown relative importance of specific adult subgroups in transmitting infection; possible polymorphism of B. pertussis; a lack of standardized clinical and laboratory case definitions for pertussis; and poor availability and application of rapid, easy-to-use and inexpensive laboratory diagnostic techniques. The final paper in the section examines the role that adolescents and adults play in perpetuating the spread of B. pertussis and how this may be influenced by immunization programs. Section 2 describes the rates and clinical spectrum of morbidity and mortality caused by pertussis in infants, adolescents and adults. The available evidence confirms that the majority of pertussis cases still occur in children.

This publication has 1 reference indexed in Scilit: