Study design
This was a parallel group, controlled (against standard of care, SoC), randomized trial, including a screening period (0–1 days), 14 days of treatment and 14 days of follow-up by telephone. The study was conducted at six sites across India. Using the screening data entered by the attending physician(s) into the online app designed specifically for this trial (see data collection below), patients were randomized by the online app within 24 hours of admission to hospital into one of two arms: SoC or SoC and doxycycline (SoC+Doxy). The study was approved by ethics committees from Fortis Hospital (EC Ref No:220/EC/PI/2020) on 30.09.2020, and from CMRI (Ref Nr: IEC/01/2021/ACD-CT/APRV/05). All patients gave their written informed consent. The trial was registered on the Clinical Trials Registry–India (final registration number CTRI202105033867). The full study protocol is available at: 