inclusion criteria: - provision of informed consent - exposure to a covid19 case within 4 days as either a household contact or occupational exposure, or - symptomatic covid19 case with confirmed diagnosis within 4 days of symptom onset or symptomatic high risk exposure with known covid19 contact and within 4 days of symptom onset;

inclusion criteria: - provision of informed consent - exposure to a covid19 case within 4 days as either a household contact or occupational exposure, or - symptomatic covid19 case with confirmed diagnosis within 4 days of symptom onset or symptomatic high risk exposure with known covid19 contact and within 4 days of symptom onset;