Risk factors for the development of severe or very severe respiratory syncytial virus-related lower respiratory tract infection in Indian infants: A cohort study in Melghat, India.

Objectives: Respiratory syncytial virus (RSV) is undoubtedly the single most important cause of severe lower respiratory tract infection (LRTI) globally. While new prevention measures in young infants have become available, their use in developing countries is likely many years away. While risk factors for severe or very severe RSV LRTI in impoverished rural areas likely differ to urban areas, there are very few studies, especially those conducted in India, the major country contributing to the global burden of disease.

Methods: Active surveillance for acute LRTI in enrolled infants and children <2 years of age, was conducted through weekly home visits in 93 villages of Melghat, India, from August 2016 to December 2020. Local hospitals and primary health centres were surveyed for admissions of enrolled subjects. Nasopharyngeal swabs were collected from children with severe, or very severe LRTIs and all who died, with RSV testing using nucleic acid tests at ICMR, National Institute of Virology Pune. Risk factors for both RSV associated and non-RSV associated, severe and very severe LRTI were identified through univariate and multivariate logistic regression.

Results: There were 483 severe or very severe RSV LRTI cases and 2807 non-RSV severe or very severe LRTI infections in a cohort of 13,318 children. Weight for age z-score ≤-2, the use of kerosene or wood for cooking, obtaining drinking water from a public tap and low gestational age significantly increased the risk of RSV LRTI. A higher wealth score index and water purification were protective. Comparison with non-RSV LRTI showed male sex as an additional risk factor. The analysis highlighted the risk of kerosene use [OR = 17.8 (3.0-104.4) (p ≤ 0.001)] and [OR = 3.4 (0.8-14.4) (p ≤ 0.05)] for RSV and non-RSV LRTIs, respectively.

Conclusions: Nutritional status and environmental air quality are predisposing factors for developing an RSV LRI in young children, factors which are amenable to environmental and behavioural interventions.