[Human Vaccines 2:3, 129-133, May/June 2006]; ©2006 Landes Bioscience
Prevalence of Pneumococcal Bacteremia Among Children 40˚C, rectal) became a standard of ambulatory care in Emergency Rooms (ERs) of the government Children’s Hospitals in Chile’s Metropolitan Region (MR) in 1999; thereafter, invasive pneumococcal disease (IPD) incidence doubled over preceding years’ estimates limited to hospitalizations. We studied IPD among children with moderate (>39˚C but 2-fold. However, economic and logistical constraints preclude such a practice.
Received 01/07/06; Accepted 04/21/06
Previously published online as a Human Vaccines E-publication: http://www.landesbioscience.com/journals/vaccines/abstract.php?id=2894
KEY WORDS Streptococcus pneumoniae, pneumococcus, bacteremia, vaccine, fever, infants, children, epidemiology, disease burden
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*Correspondence to: Rosanna Lagos; Coordinator, Centro para Vacunas en Desarrollo, Chile (CVD-Chile); Hospital de Niños; Roberto del Rio Avenida Professor Zanartu 1085; Santiago, Chile; Tel.: +56.2.737.5022; Fax: +56.2.777.5766; Email:
[email protected]
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for Vaccine Development; University of Maryland School of Medicine; Baltimore, Maryland USA
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2Hospital de Niños Roberto del Río; Santiago, Chile
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1Centro para Vacunas en Desarrollo, Chile; Santiago, Chile
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Rosanna M. Lagos1,2,* Alma E. Muñoz1 Myron M. Levine3
emergency room metropolitan region invasive pneumococcal disease expanded program of immunization Hib Haemophilus influenzae type b CVD-Chile Centro para Vacunas en Desarrollo, Chile S. pneumoniae Streptococcus pneumoniae
In controlled field trials in both industrialized and developing countries, 7-valent (types 4, 6B, 9V, 14, 18C, 19F and 23F) and 9-valent (plus types 1 and 5) pneumococcal conjugate vaccines have demonstrated impressive efficacy in protecting infants and toddlers against invasive disease (e.g., meningitis, septic arthritis, etc.) and pneumonia caused by “vaccine serotypes”.1-4 Extensive surveillance in the United States has not only demonstrated a precipitous decrease in invasive pneumococcal disease in the target age groups (infants and young children), but has convincingly demonstrated indirect protective effects, as incidence rates have also fallen significantly in nonvaccinated age groups, including young adults and the elderly.5,6 These robust results have raised global interest for the introduction of such vaccines in the world’s least developed countries (where pneumonia and invasive pneumococcal disease are major causes of mortality)4 and in “transitional” countries where, although mortality may be low, morbidity from pneumococcal disease is believed to represent an important cause of hospitalizations and health center visits and constitutes a drain on limited health resources.7,8 While the beneficial effects of immunization with pneumococcal conjugate vaccines are incontestable, these complex vaccines are demanding to manufacture (e.g., supply problems have occurred in the USA). As a consequence, they are considerably more expensive than the vaccines currently administered to infants in the Expanded Program on Immunization (EPI) in developing and transitional economy countries. Understandably, public health authorities in such countries will need a strong evidence base to make decisions about introduction of these vaccines into their national EPI, a lesson well taught from the global experience of uptake of Haemophilus influenzae type b (Hib) conjugate vaccine.9 Chile was the second nonindustrialized country in the world to introduce Hib conjugate into its EPI.10 That action followed measurements of disease burden,11 clinical trials of Hib conjugate vaccines in Chilean infants,12-14 estimation of cost-benefit,15 and a large-scale post-licensure controlled assessment of the impact of selective use of Hib conjugate in the
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ACKNOWLEDGEMENTS
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This project was funded by a grant from GSKBiologicals and by the Fundación CVD-Chile.
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Human Vaccines
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Pneumococcal Bacteremia in Febrile Children
EPI.16 Following the paradigm established for introduction of the Hib conjugate,10 during the past 10 years CVD-Chile has carried out epidemiologic studies in the Metropolitan Region (MR) of Chile to estimate the burden of vaccine-preventable pneumococcal disease.7,8 The generation of such disease burden data will be imperative to allow the Chilean Ministry of Health and the Ministry of Finance to make an informed public health and economic decision about the possible routine use of pneumococcal vaccines in the Chilean EPI.7,8 Prospective, systematic, hospital-based surveillance for invasive pneumococcal disease in Chile’s MR, which has been ongoing unchanged since 1994, has shown that the incidence of severe, hospitalized cases of culture-confirmed invasive pneumococcal infection in young infants and children has remained stable over the past 10 years.1,2 A pilot blood culture surveillance study in the Emergency Rooms (ERs) of the three Children’s Hospitals of the MR, carried out from August 1, 1998 to July 31, 1999 among ambulatory patients 6–35 months of age with high fever (rectal temperature >40˚C) and no overt focus of infection, showed that 18 of 1503 children (1.2%) cultured had S. pneumoniae bacteremia.2 Based on this information, the Directors of ERs of the nine MR government hospitals that provide urgent care to pediatric patients issued directives, effective August 1, 1999, making it a routine standard of pediatric care to obtain a blood culture from any child
