What Are the Implications for Childhood Pneumonia of Successfully Introducing Hib and Pneumococcal Vaccines in Developing Countries?

Pneumonia is the single commonest cause of death in children under five years old, accounting for 2 million out of 10 million childhood deaths worldwide [1]. Severe pneumonia is an important diagnostic syndrome within the World Health Organization (WHO)/UNICEF system for triage and clinical management in developing countries, the Integrated Management of Childhood Illness (IMCI). The objective of IMCI is early recognition of disease and timely access to effective therapy; for severe pneumonia, this means referral to hospital and treatment with lifesaving antibiotics directed against the principal etiological agents, Streptococcus pneumoniae and Haemophilus influenzae type b (Hib) [2]. The Global Alliance on Vaccines and Immunization (GAVI) is now supporting introduction of conjugate Hib vaccine into routine childhood immunization programs in 24 developing countries [3], and introduction of 7-valent pneumococcal conjugate vaccine (PCV) will begin in three countries in 2008 [4]. As global coverage of these vaccines expands, the principal etiological causes of severe pneumonia will largely be controlled by immunization. The incidence of severe pneumonia and its attendant mortality may be reduced by 50% or more. If so, this will become a historic public health achievement and a pattern to emulate in other significant infectious diseases of poverty. However, even if these highly effective vaccines reduce pneumonia mortality by half, residual deaths from pneumonia in childhood will still outnumber deaths from malaria [5]. A tremendous global health problem will remain. Furthermore, as much of our thinking about pneumonia is dominated by the two vaccinepreventable pathogens, we will be poorly positioned to diagnose and manage these residual cases. In this policy discussion paper, we look to the future and imagine the implications of a successful vaccination campaign against H. influenzae type b and pneumococcus. Our assumption in doing so is that the burden of childhood pneumonia due to these infections will be dramatically reduced, and we discuss how such a reduction will influence the clinical diagnosis, classification, management, and control of pneumonia. Although significant global coverage of 10or 13valent pneumococcal vaccines may be 10–15 years ahead, the slow translation of ideas to research, policy, and then practice in developing countries suggests that we need to anticipate this scenario now. What Are the Implications for Childhood Pneumonia of Successfully Introducing Hib and Pneumococcal Vaccines in Developing Countries?