ChAdOx1 nCoV-19

An adaptive phase I/II randomized placebo-controlled trial to determine safety, immunogenicity and efficacy of non-replicating ChAdOx1 SARS-CoV-2 vaccine in South African adults living without HIV; and safety and immunogenicity in adults living with HIV.


The COVID-19 pandemic has significantly disrupted healthcare systems and economies worldwide. Despite efforts, the virus continues to spread, with no specific treatments available, highlighting the urgent need for vaccine development. South Africa, early in its outbreak with 3,500 cases and 58 deaths as of 22 April 2020, expects its peak toward the end of July 2020. Modeling data predicts multiple global waves of COVID-19 through 2022.

Live attenuated viruses, though highly immunogenic, pose biosafety challenges and risks, especially for older adults with comorbidities. Replication-deficient vectors avoid these risks and offer native antigen presentation and T cell immunity advantages.Chimpanzee adenovirus vaccine vectors, such as ChAdOx1, have been safely administered and shown to be highly immunogenic. A ChAdOx1 vaccine for another betacoronavirus (MERS-CoV) induced neutralizing antibodies in recent trials.

A UK phase I/II trial started in April 2020, with data supporting larger phase II/III studies. The South African study will enroll adults with and without HIV to assess the safety, immunogenicity, and efficacy of ChAdOx1-nCoV-19. Enrollment in South Africa will follow safety reviews and occur alongside expanded UK enrollment.


  • Professor Shabir Madhi, National Principal Investigator
  • Professor Lee Fairlie, Principal Investigator
  • Dr Faeezah Patel, Sub-Investigator
  • Dr Elizea Horne, Sub-Investigator
  • Dr Gabriella Benade, Sub-Investigator
  • Mrinmayee Dhar, Sub-Investigator
  • Robert Kieser, Sub-Investigator
  • Musawenkosi Mlotshwa, Sub-Investigator
  • ¬†Tiffany Seef, Clinical associate
  • Othusitse Segalo, Clinical Associate

Latest Update:

April 2024

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Research Brief

ChAdOx1 nCoV-19

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