Data collection: The demographic, clinical, treatment and outcome data will be collected by investigator and email the form to the study coordinator, Arunaloke Chakrabarti. Outcome will be measured on day of discharge/death/30 and 120 days (whichever is earlier) after the diagnosis of the IMI. The date of diagnosis of an IMI is the day on which the diagnosis is defined as proven or probable. For cases that were enrolled as probable but subsequently became proven, the date of diagnosis is the earlier date. In addition, each center will also obtain data from its relevant hospital authority on the total number of discharges and deaths in ICUs for the period of April 1, 2016 to March 31, 2017.