Transmission of COVID19 in Crowded Environments

The major risk mitigation factors recommended by World Health Organisation and others - physical distancing and hygiene - are extremely difficult to implement in much of Africa. Newly diagnosed SARS-CoV-2 index patients will be identified and recruited from a mobile clinic and local community clinics conducting SARS-CoV-2 testing. Index cases and their households will be invited to enroll. The study design is a type 2 hybrid cluster (household) randomised controlled trial, with outcomes assessed on index patients and their household contacts. 120 consecutively newly diagnosed index patients (GeneXpert severe acute respiratory syndrome coronavirus 2 PCR) and up to 6- 8 household contacts will be invited to participate in the trial as part of the prospective observational study evaluating transmission and symptoms. After completing consent, households will be randomised in a 1:1 ratio in blocks of 10 (60 households per group). Klipfontein is a resource-limited, densely populated, high HIV/tuberculosis disease burden areas in Cape Town. Newly diagnosed COVID19 cases will be identified from two sources: screening conducted in Desmond Tutu Health Foundation mobile screening units and local public sector clinics working closely with Desmond Tutu Health Foundation. Consecutive cases (n=120 cases and households) will be invited to participate in the randomised trial and prospective longitudinal follow up of up to 6- 8 household contacts. The contacts will be followed up after informed consent to SARS-CoV-2 screening, symptomatic questionnaires weekly up to 1 month. After enrolment, the household will be randomised to the infection mitigation intervention or enhanced usual care messaging. Baseline demographic, household characteristics questionnaire will be administered, and each household occupant invited to participate. Following consent procedures, household contacts (HHC) will be screened at baseline and weekly for 4 weeks for evidence of COVID19 infection. Specifically, the research team will conduct SARS-CoV-2 GeneXpert PCR testing and antibody serology. They will collate self- administered daily symptom checks on a weekly basis. The investigators will recruit 120 households over 1-11 months. The investigators will initiate a prospective longitudinal follow up of the household contacts of each case for 4 weeks in each case.

The investigators will calculate proportion of SARS-CoV-2 transmission from index cases in each household over 4- week period and describe the proportion of symptomatic and asymptomatic SARS-CoV-2 infection in a high density, low resourced community. Investigate the impact of the infection mitigation intervention by comparing incidence in households randomised to intervention versus standard of care. Secondary outcomes for the trial will include clinical outcomes (hospitalisations, death), linkages to care for people, psychosocial functioning, and stigma.