1. Male or Female participants >/= 18 years of age at high-risk of SARS-CoV-2/COVID-19 infection 2. Participants with high-risk of infection to COVID-19 cases defined as: • Health care workers (physicians, nurses, paramedical staff) working in direct contact with COVID-19 patients • Other high-risk participants who are aged >/= 65 years or aged >/= 18 years with co-morbidities such as: • Insulin dependent or non-insulin dependent diabetes mellitus • Hypertension • Past history of completed acute myocardial infarction • Cardiac failure of NYHA class 2 and above • Rheumatic heart disease • Chronic obstructive pulmonary disease, bronchiectasis or emphysema • Chronic suppurative lung disease • Cystic fibrosis • Pulmonary fibrosis 3. Negative screening for SARS-CoV-2 infection (using a validated and approved PCR or serology test method) at time of consent 4. Capable of giving informed consent

1. Male or Female participants >/= 18 years of age at high-risk of SARS-CoV-2/COVID-19 infection 2. Participants with high-risk of infection to COVID-19 cases defined as: • Health care workers (physicians, nurses, paramedical staff) working in direct contact with COVID-19 patients • Other high-risk participants who are aged >/= 65 years or aged >/= 18 years with co-morbidities such as: • Insulin dependent or non-insulin dependent diabetes mellitus • Hypertension • Past history of completed acute myocardial infarction • Cardiac failure of NYHA class 2 and above • Rheumatic heart disease • Chronic obstructive pulmonary disease, bronchiectasis or emphysema • Chronic suppurative lung disease • Cystic fibrosis • Pulmonary fibrosis 3. Negative screening for SARS-CoV-2 infection (using a validated and approved PCR or serology test method) at time of consent 4. Capable of giving informed consent