inclusion criteria: - health care workers and allied health care staff working in covid wards, covid icu, non covid icu (this will include all specialty icus in the hospital), casualty/emergency, operation theatre and pathology lab of the hospital - health care workers and allied health care staff involved in performing high risk procedures like suctioning, intubation, nebulized medications, chest physiotherapy, other aerosol generating procedures and handling pathology samples - negative covid 19 rt-pcr test within last 3 days of screening - covid 19 vaccinated or non-vaccinated

inclusion criteria: - health care workers and allied health care staff working in covid wards, covid icu, non covid icu (this will include all specialty icus in the hospital), casualty/emergency, operation theatre and pathology lab of the hospital - health care workers and allied health care staff involved in performing high risk procedures like suctioning, intubation, nebulized medications, chest physiotherapy, other aerosol generating procedures and handling pathology samples - negative covid 19 rt-pcr test within last 3 days of screening - covid 19 vaccinated or non-vaccinated