Measuring progress on preventing pneumonia deaths: are we there yet?
Authors: Cynthia G Whitney
Journal: The Lancet Infectious Diseases (2017)

In The Lancet Infectious Diseases, the GBD 2015 LRI Collaborators provide estimates of the burden of illnesses and deaths from lower respiratory tract infections as a group and specific numbers for four common aetiologies—Streptococcus pneumoniae (pneumococcal pneumonia), Haemophilus influenzae type b (Hib), influenza, and respiratory syncytial virus (RSV).1GBD 2015 LRI CollaboratorsEstimates of the global, regional, and national morbidity, mortality, and aetiologies of lower respiratory infections in 195 countries: a systematic analysis for the Global Burden of Disease Study 2015.Lancet Infect Dis. 2017; (published online August 23.)http://dx.doi.org/10.1016/S1473-3099(17)30396-1Google Scholar According to the models presented, lower respiratory tract infections remain a top cause of mortality for all ages—the fifth leading cause of deaths overall and second in children younger than 5 years. The burden of lower respiratory tract infections is immense, with 2·7 million deaths in 2015 alone, including 704 000 deaths in children younger than 5 years. Clearly, the need to press ahead on multiple fronts to reduce this burden is great. Progress is being made. The new estimates show that deaths due to respiratory infections decreased between 2005 and 2015, in particular in young children. However, the authors' models show how the poorest countries in sub-Saharan Africa and south Asia still have the largest burden of deaths from respiratory infections, with three of every four deaths from respiratory infections worldwide occurring in these two regions. Additionally, estimated reductions in pneumonia mortality over the past decade were smaller in sub-Saharan Africa (21·4%, 95% UI 11·0–30·8) than the overall worldwide reductions (36·9%, 31·6–42·0). WHO and UNICEF lead a global effort to reduce childhood deaths from pneumonia, with key strategies summarised in the integrated Global Action Plan for Pneumonia and Diarrhoea (GAPPD).2WHO and The United Nations Children's Fund (UNICEF) 2013Ending preventable child deaths from pneumonia and diarrhoea by 2025: the integrated global action plan for pneumonia and diarrhoea (GAPPD).http://www.who.int/maternal_child_adolescent/documents/global_action_plan_pneumonia_diarrhoea/en/Date: 2013Google Scholar The GAPPD highlights adequate nutrition, access to appropriate treatment, reducing indoor air pollution, and vaccination as interventions crucial to reducing pneumonia mortality in children. The models presented by the GBD 2015 LRI Collaborators1GBD 2015 LRI CollaboratorsEstimates of the global, regional, and national morbidity, mortality, and aetiologies of lower respiratory infections in 195 countries: a systematic analysis for the Global Burden of Disease Study 2015.Lancet Infect Dis. 2017; (published online August 23.)http://dx.doi.org/10.1016/S1473-3099(17)30396-1Google Scholar show that decreases in exposure to air pollution and child undernutrition contributed strongly to the reductions in years of life lost from pneumonia over the past decade, with decreases in respiratory infection DALYs of 8·9% attributed to reductions in undernutrition and 4·3% attributed to reductions in air pollution. In future models, making similar estimates that quantify the benefits seen from the introduction of the pneumococcal conjugate vaccine and Hib vaccine would be useful. The GBD 2015 LRI Collaborators used state-of-the-art modelling techniques and exhaustively considered all inputs to generate estimates that will be useful for policy makers and investors in many individual countries and at the regional and global levels. Nonetheless, other experts might decide to assemble the data differently or use other input values, resulting in different estimates. For example, WHO provides a higher estimate of pneumonia deaths in children younger than 5 years in 2015 (920 000 globally)3WHOGlobal Health Observatory data repository: acute lower respiratory infections. Geneva: World Health Organization.http://apps.who.int/gho/data/view.main.CM1002015WORLD-CH9?lang=enGoogle Scholar than that estimated by the GBD 2015 LRI Collaborators. A revision of this official WHO estimate is expected later this year,4Johns Hopkins Bloomberg School of Public HealthMaternal, newborn and child cause of death: estimation of deaths by cause for women, newborns and children under five (global, by country).http://idfive.jhsph.edu/centers-and-institutes-partial/international-health/centers-and-institutes/institute-for-international-programs/current-projects/maternal-child-epidemiology-estimation/maternal-newborn-and-child-cause-of-death/Google Scholar and models are being developed to provide new estimates of RSV burden. Although numbers might differ between approaches, the high burdens of pneumonia deaths in south Asia and sub-Saharan Africa are consistent between models. Trying to estimate the burden of pneumonia, in particular by aetiology and for every country, is challenging. Much of the input data is missing or of low quality, requiring modellers to assume values for some countries. Many low-income countries have no vital registration system to accurately measure births or deaths, and capacity to establish specific causes of deaths is limited to verbal autopsies. Even in high-income settings or high-quality aetiology studies, establishing the aetiology of pneumonia is difficult because specimens are rarely available from the site of infection (ie, inside the lung).5Jain S Williams DJ Arnold SR et al.Community-acquired pneumonia requiring hospitalization among U.S. children.N Engl J Med. 2015; 372: 835-845Crossref PubMed Scopus (929) Google Scholar, 6Levine OS O'Brien KL Deloria-Knoll M et al.The pneumonia etiology research for child health project: a 21st century childhood pneumonia etiology study.Clin Infect Dis. 2012; 54: S93-S101Crossref PubMed Scopus (141) Google Scholar Techniques such as using vaccination as a probe to establish the burden of a particular aetiology are useful, but such data are scarce and typically more useful for measuring illnesses than deaths.7Feikin DR Scott JA Gessner BD Use of vaccines as probes to define disease burden.Lancet. 2014; 383: 1762-1770Summary Full Text Full Text PDF PubMed Scopus (78) Google Scholar A new initiative, the Child Health and Mortality Prevention Surveillance, aims to assess causes of death in children younger than 5 years using small samples of tissue collected post-mortem. This method could be a breakthrough for pneumonia aetiology research, if treatment received before death does not limit the ability to detect infecting organisms in lung tissue. In the future, methods for attributing deaths should allow for pneumonia to have more than one aetiology, because pneumonia deaths are often caused by concomitant infections with bacteria and viruses. The numbers generated by the models presented by the GBD 2015 LRI Collaborators1GBD 2015 LRI CollaboratorsEstimates of the global, regional, and national morbidity, mortality, and aetiologies of lower respiratory infections in 195 countries: a systematic analysis for the Global Burden of Disease Study 2015.Lancet Infect Dis. 2017; (published online August 23.)http://dx.doi.org/10.1016/S1473-3099(17)30396-1Google Scholar might have limitations, yet they paint a vivid picture of the progress still to be made in the prevention of pneumonia deaths. These numbers also highlight the places where most deaths are occurring and, therefore, where interventions are most needed. Effective interventions for reducing pneumonia deaths are available, and a vaccine to prevent RSV infection could be available in the near future. With continued resources and attention, modelled estimates of pneumonia deaths, as well as actual numbers, can continue to decrease. I declare no competing interests. The findings and conclusions in this report are those of the author and do not necessarily represent the views of the Centers for Disease Control and Prevention. Estimates 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 2015LRIs are the leading infectious cause of death and the fifth-leading cause of death overall; they are the second-leading cause of DALYs. At the global level, the burden of LRIs has decreased dramatically in the last 10 years in children younger than 5 years, although the burden in people older than 70 years has increased in many regions. LRI remains a largely preventable disease and cause of death, and continued efforts to decrease indoor and ambient air pollution, improve childhood nutrition, and scale up the use of the pneumococcal conjugate vaccine in children and adults will be essential in reducing the global burden of LRI. Full-Text PDF Open Access