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  Exclusion Criteria:  Unable or refused to consent Current respiratory illness, rhinitis and/or allergy Currently participating in any other clinical trial Beard or facial hair