Viral etiology of pneumonia among severely malnourished under-five children in an urban hospital, Bangladesh

Background In Bangladesh, pneumonia has a higher mortality among malnourished children aged <5 years. Evaluating pneumonia etiology among malnourished children may help improve empiric treatment guidelines. Methods During April 2015—December 2017, we conducted a case-control study among severe acute malnourished (SAM) children aged <5 years admitted to the Dhaka hospital of International Centre for Diarrhoeal Disease Research, Bangladesh (icddr,b). We enrolled hospital admitted SAM children with clinical or radiological pneumonia as cases (during April 2015 to March 2017) and hospital admitted SAM children without any respiratory symptom in the past 10 days before admission as controls (during February 2016 to December 2017). We tested nasopharyngeal wash from both case and control for respiratory syncytial virus (RSV), human metapneumovirus (HMPV), influenza viruses, human parainfluenza viruses (HPIV), rhinovirus and adenovirus by singleplex real-time reverse transcriptase polymerase chain reaction. To identify the independent association of pneumonia with viral pathogens during February 2016 to March 2017, we used multivariable logistic regression for calculating adjusted odds ratios. Results We enrolled 360 cases and 334 controls. For case and control the median age was 8 months (IQR: 5–13) and 11 months (IQR: 6–18) (p = 0.001) respectively. Weight/age Z-score was -4.3 (SD ±0.7) for cases and -4.1 (SD ±1.1) for controls (p = 0.01). Among cases 68% had both clinical and radiological pneumonia, 1% had clinical pneumonia and 31% had only radiological pneumonia. Respiratory virus detection was high in cases compared to controls [69.9% (251) vs. 44.8% (148), p = 0.0001]. The most frequently detected viruses among cases were rhinoviruses (79, 22.0%) followed by RSV (32, 8.9%), adenovirus (23, 6.4%), HPIV (22, 6.1%), influenza virus (16, 4.5%), and HMPV (16, 4.5%). Among the controls, rhinoviruses (82, 24.8%) were most commonly detected one followed by adenovirus (26,7.9%), HMPV (5, 1.5%), HPIV (4, 1.2%), RSV (3, 0.9%), and influenza virus (2, 0.6%). RSV (OR 13.1; 95% CI: 1.6, 106.1), influenza virus (OR 8.7; 95% CI: 1.0, 78.9), HPIV (3.8; 95% CI: 1.0, 14.8), and HMPV (2.7; 95% CI: 1.3, 5.5) were independently associated with pneumonia while compared between 178 cases and 174 controls. Conclusion Viral etiology of pneumonia in SAM children were mainly attributable to RSV, influenza, HPIV and HMPV. Our study findings may help in planning further studies targeting vaccines or drugs against common respiratory viruses responsible for pneumonia among SAM children.