The bacterium Haemophilus influenzae type b (Hib) causes at least 3 million cases of severe disease each year, and about 400,000 children die annually due to pneumonia or meningitis caused by Hib. Vaccines against Hib are both safe and highly effective at reducing disease and deaths from Hib infection, and so the World Health Organization recommends the introduction of Hib vaccines worldwide. In a policy paper in PLoS Medicine, M. Carolina Danovaro-Holliday (Pan American Health Organization; PAHO) and colleagues examine the progress of Hib vaccine introduction in the Americas.
They find that by the end of 2006, all countries of the Americas, except Haiti, had included Hib in their immunization schedule. Factors that favored this region-wide Hib vaccine adoption, they say, included strong political will, data supporting a high Hib disease burden and the positive impact of Hib vaccination in early adopters, and the existence of a mechanism called the Revolving Fund for bulk purchase of vaccines. But "efforts are still needed," say the authors, "to improve vaccination coverage and to strengthen invasive bacterial disease surveillance in developing countries."
Citation: Danovaro-Holliday MC, Garcia S, de Quadros C, Tambini G, Andrus JK (2008) Progress in vaccination against Haemophilus influenzae type b in the Americas. PLoS Med 5(4): e87
How will childhood pneumonia change if vaccine campaigns are a success?
In developing countries, two bacteria, pneumococcus and Hib, are the dominant causes of severe pneumonia in children. The introduction of vaccines against these diseases could reduce the global burden of severe pneumonia by about half. In this week's PLoS Medicine, J. Anthony G. Scott and Mike English--researchers at the Kenya Medical Research Institute--Wellcome Trust Collaborative Research Programme, Kenya--argue that the present classification and management guidelines for childhood pneumonia are founded on the dominance of these two organisms and will rapidly become obsolete as these vaccines are introduced.
The remaining cases of pneumonia, they say, will have a wide variety of causes and will include many cases of TB and noninfectious respiratory disease. This diversity of causes will make the diagnosis, classification, and management of pneumonia much more complex and expensive in the future. "To be relevant to future policy," say the authors, "research in the areas of pneumonia diagnosis, classification, prevention, or management should begin to anticipate this scenario now."
Citation: Scott JAG, English M (2008) What are the implications for childhood pneumonia of successfully introducing Hib and pneumococcal vaccines in developing countries? PLoS Med 5(4): e86.
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