Methods: We estimated the burden of pneumonia and severe pneumonia in children less than five years using a risk factor-based model. A systematic literature review was conducted to identify published data on the incidence of pneumonia from community-based longitudinal studies and a summary estimate was calculated. We estimated state-specific incidence rates for WHO-defined clinical pneumonia for 2000 and 2015 using Poisson regression and the prevalence of risk factors in each state obtained from National Family Health Surveys (NFHS). From clinical pneumonia studies, we identified studies reporting the proportion of clinical pneumonia cases with lower chest wall indrawing to estimate WHO-defined severe pneumonia cases. We used the estimate of the proportion of cases with lower chest wall indrawing to estimate WHO-defined severe pneumonia cases for each state.
Findings: We estimated there were 49.8 (95% uncertainty interval [UI]: 9.1-174.2) million pneumonia cases in HIV-uninfected children less than five years in India in 2015—a 41% reduction since 2000 when there were an estimated 83.8 (95% UI: 14.0- 300.8) million pneumonia cases in this age group. The national incidence of pneumonia in children in India was 657 (95% UI: 110-2 357) cases per 1000 children less than five in 2000 and 403 (74-1408) cases per 1000 children in 2015. We also estimated there were 8.4 (95% UI: 1.2-31.8) million severe pneumonia cases with a corresponding incidence rate of 68 (9-257) cases per 1000 children less than five years and a case fatality ratio of 0.38% (0.11-2.10%) in 2015. The greatest number of pneumonia cases in HIV-uninfected children in 2015 was estimated to have occurred in Uttar Pradesh (12.4 [95% UI: 2.1-45.0] million), Bihar (7.3 [1.3-26.1] million), and Madhya Pradesh (4.6 [0.7-17.0] million) in 2015. Kerala had the greatest reduction with an 82% reduction between 2000 and 2015. Two states were estimated to have pneumonia incidence rates greater than 500 cases per 1000 children less than five years in 2015: Uttar Pradesh (565 [95% UI: 94-2 047]) and Madhya Pradesh (563 [88-2084]).
Interpretation: Pneumonia and severe pneumonia cases were estimated to have decreased between 2000 and 2015. Improvements in socioeconomic indicators and specific government initiatives are likely to have contributed to declines in the prevalence of pneumonia risk factors in many states. However, pneumonia incidence rates in many states remain worryingly high. The introduction of new vaccines that target pneumonia pathogens and reduce risk factors will help further reduce the burden of pneumonia in the country.