COVID-19 mortality in 1984 Bhopal gas tragedy survivors: implications for chemically exposed populations

Leakage of methyl isocyanate from the Union Carbide plant in Bhopal, India, killed thousands and left deleterious trans-generational effects. Gas-exposed populations experience higher rates of lung and metabolic diseases, and immune dysregulation, all associated with adverse outcomes in coronavirus disease 2019 (COVID-19). We used publicly available, official data from government sources to estimate COVID-19-associated crude mortality in populations with and without a history of gas exposure. Overall, there were 1240 deaths among patients hospitalized with known COVID-19 in Bhopal, of which 453 (36.53%) were in gas-exposed individuals, 726 (58.55%) were in gas-unexposed individuals and the exposure status of 61 (4.92%) individuals could not be determined. There were 351 and 375 deaths in gas-unexposed people in the first (April 2020-February 2021) and second (March 2021-July 2021) waves, respectively; in the gas-exposed population, there were 300 and 153 deaths in the two respective waves. The overall annualized crude mortality of COVID-19 was 3.84 (95% CI 3.41 to 4.33) times higher in the gas-exposed population at 83.6 (95% CI 76.1 to 91.7) per 100 000 compared with the gas-unexposed population, at 21.8 (95% CI 20.2 to 23.4) per 100,000. When stratified by age, compared with unexposed people, the gas-exposed individuals experienced 1.88 (95% CI 1.61 to 2.21) and 1.24 (95% CI 1.02 to 1.50) times the mortality rates in the age groups of 35-65 and >65 y, respectively. These findings indicate that gas-exposed individuals are likely to have a higher risk of severe COVID-19 and death and need to be specifically targeted and recognized for preventive and promotive efforts.