Seasonal variation and etiologic inferences of childhood pneumonia and diarrhea mortality in India

Abstract

Future control of pneumonia and diarrhea mortality in India requires understanding of their etiologies. We combined time series analysis of seasonality, climate-region, and clinical syndromes from 243,000 verbal autopsies in the nationally-representative Million Death Study. Pneumonia mortality at 1 month-14 years was greatest in January (Rate ratio (RR) 1.66, 99%CI 1.51-1.82; Versus the April minimum). Higher RRs at 1-11 months suggested respiratory syncytial virus (RSV) etiology. India’s humid subtropical region experienced a unique summerpneumonia mortality. Diarrhea mortality peaked in July (RR 1.66, 1.48-1.85) and January (RR 1.37, 1.23-1.48), while deaths with fever and bloody diarrhea (indicating enteroinvasive bacterial etiology) showed little seasonality. Combining mortality at ages 1-59-months in 2015 with prevalence surveys, we estimate 40,600 pneumonia deaths from Streptococcus pneumoniae, 20,700 from RSV, 12,600 from influenza, and 7,200 from Haemophilus influenza type b and 24,700 diarrheal deaths from rotavirus. Careful mortality studies can elucidate etiologies and inform vaccine introduction.