Pneumococcal and Haemophilus influenzae type b disease: moving numbers in the right direction
Authors: Cynthia G Whitney
Journal: The Lancet Global Health (2018)

In The Lancet Global Health, Brian Wahl and colleagues present results of a comprehensive model created to quantify the global burden of disease and death in children caused by two leading causes of pneumonia, meningitis, and sepsis: Streptococcus pneumoniae (pneumococcus) and Haemophilus influenzae type b (Hib).1Wahl B O'Brien KL Greenbaum A et al.Burden of Streptococcus pneumoniae and Haemophilus influenzae type b disease in children in the era of conjugate vaccine: global, regional, and national estimates for 2000–15.Lancet Glob Health. 2018; 6: e744-E757Summary Full Text Full Text PDF PubMed Scopus (480) Google Scholar The authors estimate that, in HIV-uninfected children in 2015, pneumococcal disease caused about 294 000 deaths (uncertainty range [UR] 192 000–366 000) in children aged 1–59 months and Hib caused 29 500 deaths (18 400–40 700) in children aged 1–23 months; an additional 23 000 pneumococcal deaths (15 300–28 700) and fewer than 1000 Hib deaths were estimated to have occurred in children with HIV. In other words, far too many deaths—about 900 every day—are still being caused by these two infections. Moreover, a small number of countries have exceptionally high burden; the numbers of pneumococcal deaths for just four countries—India, Nigeria, the Democratic Republic of the Congo, and Pakistan—account for about half of the world's total burden. The good news is that the numbers are moving in the right direction. The authors estimate that the 2015 numbers represent a 51% (UR 7–74) reduction in pneumococcal deaths and a 90% (UR 78–96) reduction in Hib deaths from year 2000 figures for children without HIV. This is a remarkable improvement, but we have a long way to go. If the estimated global mortality rates for pneumococcal disease (45 deaths [UR 29–56] per 100 000 children) and Hib disease (4 deaths [3–6] per 100 000 children) had been reduced to those seen in the Americas (8 [5–10] and 0 [0–0] per 100 000 children, respectively),1Wahl B O'Brien KL Greenbaum A et al.Burden of Streptococcus pneumoniae and Haemophilus influenzae type b disease in children in the era of conjugate vaccine: global, regional, and national estimates for 2000–15.Lancet Glob Health. 2018; 6: e744-E757Summary Full Text Full Text PDF PubMed Scopus (480) Google Scholar it is possible that many more than 200 000 of the deaths caused by these two pathogens among young children in 2015 could have been prevented. As large as the numbers for deaths and cases are in Wahl and colleagues' Article,1Wahl B O'Brien KL Greenbaum A et al.Burden of Streptococcus pneumoniae and Haemophilus influenzae type b disease in children in the era of conjugate vaccine: global, regional, and national estimates for 2000–15.Lancet Glob Health. 2018; 6: e744-E757Summary Full Text Full Text PDF PubMed Scopus (480) Google Scholar they probably represent an underestimate of the true burden of pneumococcal and Hib disease, in spite of the authors' extensive search for input data and thoughtful modelling choices. Obtaining an accurate count is difficult for several reasons. Many low-income countries, where most pneumococcal and Hib deaths occur, do not have comprehensive systems for registering births and deaths, so simply adding up the numbers is not an option. Determining the cause of death is a very inexact process unless an autopsy is performed, and it almost never is. Determining the cause of pneumonia, in particular, is challenging because the symptoms can be similar to those of other diseases, and diagnostic testing is typically of low yield because specimens are not available from the site of infection (eg, inside the lung). Wahl and colleagues' estimates are lower but similar in magnitude to those made independently by the Global Burden of Disease collaborators (393 000 deaths from pneumococcal pneumonia and 59 000 deaths from Hib disease in children younger than 5 years in 2015),2GBD 2015 LRI CollaboratorsEstimates of the global, regional, and national morbidity, mortality, and aetiologies of lower respiratory tract infections in 195 countries: a systematic analysis for the Global Burden of Disease Study 2015.Lancet Infect Dis. 2017; 17: 1133-1161Summary Full Text Full Text PDF PubMed Scopus (411) Google Scholar providing a plausible range for those seeking to use the data. How can we reach our destination, where no child dies from a pneumococcal or Hib infection that could have been prevented? Fortunately, we have a road map, the Global Action Plan for Pneumonia and Diarrhoea (GAPPD), which outlines the route to reducing pneumonia deaths by preventing disease and improving treatment.3WHOUnited Nations Childrens FundEnding preventable child deaths from pneumonia and diarrhoea by 2025: the integrated Global Action Plan for Pneumonia and Diarrhoea (GAPPD). WHO, Geneva, Switzerland2013Google Scholar The GAPPD highlights vaccines as key interventions. Conjugate vaccines have proven to be highly effective for preventing severe pneumococcal and Hib disease in young children,4WHOPneumococcal vaccines WHO position paper—2012.Wkly Epidemiol Rec. 2012; 87: 129-144PubMed Google Scholar, 5WHOHaemophilis influenzae type b (Hib) vaccination position paper—September 2013.Wkly Epidemiol Rec. 2013; 88: 413-428PubMed Google Scholar and Wahl and colleagues credit most of the decline in deaths between 2000 and 2015 to vaccine implementation.1Wahl B O'Brien KL Greenbaum A et al.Burden of Streptococcus pneumoniae and Haemophilus influenzae type b disease in children in the era of conjugate vaccine: global, regional, and national estimates for 2000–15.Lancet Glob Health. 2018; 6: e744-E757Summary Full Text Full Text PDF PubMed Scopus (480) Google Scholar Hib vaccines are part of routine infant immunisation in all but three countries (China, Russia, and Thailand), but many countries have immunisation programmes that have not yet introduced pneumococcal conjugate vaccine or that need to improve their coverage, according to the March, 2018, report from the International Vaccine Access Center (IVAC) at Johns Hopkins Bloomberg School of Public Health.6Johns Hopkins Bloomberg School of Public Health International Vaccine Access Center (IVAC)VIEW-hub report: global vaccine introduction and implementation. A report on current global access to new childhood vaccines.https://www.jhsph.edu/research/centers-and-institutes/ivac/resources/IVAC%20VIEW-hub%20Report%20March%202018.pdfDate: March, 2018Date accessed: May 11, 2018Google Scholar The IVAC report states that more than 40% of the world's children live in countries that do not yet provide pneumococcal conjugate vaccine through their routine infant immunisation programmes. Better use of pneumococcal conjugate vaccines would prevent a large proportion of the remaining burden. Measures to prevent HIV infection in newborns have been useful for reducing child deaths and pneumococcal disease,3WHOUnited Nations Childrens FundEnding preventable child deaths from pneumonia and diarrhoea by 2025: the integrated Global Action Plan for Pneumonia and Diarrhoea (GAPPD). WHO, Geneva, Switzerland2013Google Scholar, 7von Gottberg A de Gouveia L Tempia S et al.Effects of vaccination on invasive pneumococcal disease in South Africa.N Engl J Med. 2014; 371: 1889-1899Crossref PubMed Scopus (258) Google Scholar and continued support for these measures is crucial. Other interventions, such as access to appropriate health care, clean air and water, and adequate nutrition are also needed. The estimates given by Wahl and colleagues provide an important reminder to public health leaders and policy makers that the burden of pneumococcal and Hib disease remains far too high. More can and should be done for disease prevention and to ensure appropriate treatment, and the GAPPD with its package of proven interventions outlines the needed steps. I declare no competing interests. The findings and conclusions in this report are those of the author, and do not necessarily represent the official position of the Centers for Disease Control and Prevention. Burden of Streptococcus pneumoniae and Haemophilus influenzae type b disease in children in the era of conjugate vaccines: global, regional, and national estimates for 2000–15The widespread use of Hib vaccine and the recent introduction of PCV in countries with high child mortality is associated with reductions in Hib and pneumococcal cases and deaths. Uncertainties in the burden of pneumococcal disease are largely driven by the fraction of pneumonia deaths attributable to pneumococcus. Progress towards further reducing the global burden of Hib and pneumococcal disease burden will depend on the efforts of a few large countries in Africa and Asia. Full-Text PDF Open Access