Sisonke (Together): OPEN LABEL TRIAL COVID-19

Purpose To monitor the effectiveness of the single dose Ad26.COV2.S COVID-19 vaccine among health care workers (HCW) as compared to the general unvaccinated population in South Africa Study design Open-label, single-arm phase 3B vaccine implementation study Rationale South Africa is severely affected by the global COVID-19 epidemic, but currently no vaccine has been rolled out. The recent promising results of the 'ENSEMBLE' trial conducted by Janssen in South Africa, and the availability of a limited amount of vaccine doses, provide the rationale for a cohort study of vaccinated HCWs to inform the larger vaccine rollout. Study participants Health Care workers age 18 and above working in the South African public and private health care sector (N=500 000) Study sites Department of Health Vaccine administration sites across South Africa supported by the Sisonke (Together) (VAC31518COV3012) trial Research Site Investigators and Study Staff Study duration Participants will receive a single dose of vaccine at enrolment; to monitor outcomes the DATCOV surveillance system and NICD line list will be reviewed for up to 2 years post-vaccination. A sub-cohort (approx. 850-1000 people) consisting of special sub-populations will be followed up at approx. 1, 3, 6 weeks and 6 months post vaccination. This group will also have outcomes monitored for up to a further 18 months, bringing their total follow-up duration to 2 years post-vaccination Study products Ad26.COV2.S by Janssen administered as a single injection Primary objectives • To assess the effectiveness of Ad26.COV2.S vaccine on severe COVID, hospitalizations and deaths in HCWs as compared with the general unvaccinated population in South Africa. Secondary objectives • To estimate the incidence of symptomatic SARS CoV-2 infections in HCW * To estimate vaccine uptake among HCWs in South Africa * To monitor the genetic diversity of breakthrough SARS CoV-2 infections To monitor immunological responses (neutralising, non-neutralising antibodies and T cell responses) in HCWs with breakthrough infections * To measure baseline SARS CoV-2 antibody testing to evaluate pre-existing immunity in up to 100 000 HCWs. * In a subgroup of participants (approx. 850-1000 people) including representative sub-populations of interest, e.g. elderly, immune compromised: * To compare serum neutralization and immune responses before and after vaccination at 0, 6 weeks and up to 6 months. * To explore clotting parameters post vaccination at weeks 0, 1, 3. * To monitor for asymptomatic infection Exploratory objectives To set up a comprehensive safety desk and establish a link between the national pharmacovigilance system to assist with monitoring safety and any unexpected adverse effects