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Wits University begins its second Covid-19 vaccine trial in South Africa

- Wits University

Wits is the lead institution in South Africa for a second Covid-19 vaccine trial and will begin screening participants for the NVX-CoV2373 trial today.

The Phase 2 trial in South Africa will evaluate if the nanoparticle S-protein, in the Covid-19 vaccine known as NVX-CoV2373, protects against Covid-19 disease in adults aged 18-64-years-old.

NVX-CoV2373 is produced by the biotech company, Novavax (Maryland, U.S.A). Novavax is a late-stage biotechnology company that develops next-generation vaccines for serious infectious diseases.

Wits Professor of Vaccinology, Shabir Madhi will lead the Novavax clinical trial in South Africa after having engaged personally with Novavax to motivate for clinical development of the vaccine to be undertaken in this country.

Wits Professor of Vaccinology Shabir Madhi is Executive Director of VIDA leads both the Oxford and Novavax Covid19 vaccine trials in South Africa

Madhi, who is the Executive Director of the South African Medical Research Council Vaccines and Infectious Diseases Analytics Research Unit (VIDA) at Wits and the Faculty of Health Sciences Dean-elect, also leads the South African Ox1Cov-19 Vaccine VIDA-Trial launched on 23 June, in association with University of Oxford and the Jenner Institute.

The Novavax vaccine in the South African trial leverages technology used successfully to develop vaccines against influenza (flu) virus and experimental vaccines against Ebola and Respiratory Syncytial Virus (RSV).

Madhi previously collaborated with Novavax as a lead investigator on the RSV vaccine for pregnant women, which aimed to prevent the most common cause of pneumonia in babies.

About the Novavax vaccine: NVX-CoV2373

The Novavax vaccine candidate is called NVX-CoV2373. This vaccine candidate is engineered from the genetic sequence of SARS‑CoV‑2, the virus that causes Covid-19 disease. 

In preclinical studies, NVX‑CoV2373 demonstrated the elicitation of antibodies that block the binding of spike protein to receptors targeted by the virus – this is a critical aspect for effective vaccine protection.

Studies of this Novavax vaccine in non-human primates have shown protection against SARS-Cov-2 infection in upper airways (nasal passages) as well as protection against lower airway (lung) disease. 

Safety and immunogenicity [the ability of a foreign substance, such as an antigen, to provoke an immune response] data from part 1 of the Novavax Phase 1/2 randomized, observer-blinded, placebo-controlled trial of its Covid‑19 vaccine with and without Matrix‑M™ adjuvant in healthy adults 18-59-years-old, conducted in Australia, have been submitted to the U.S. Food and Drug Administration and an independent safety monitoring committee.

In this Phase 1 clinical trial, NVX-CoV2373 was generally well-tolerated and elicited robust antibody responses numerically superior to that seen in human convalescent sera. The data have been submitted for peer-review to a scientific journal and are available online.

Why South Africa?

“The major motivation for Covid-19 vaccines being evaluated at an early stage in South Africa is to generate evidence in the African context on how well these vaccines work in settings such as our own,” says Madhi.

“This would enable informed decision-making when advocating for the adoption of this [NVX-CoV2373 vaccine candidate] or other Covid-19 vaccines in African countries, once they are shown to be safe and effective.

Participating in the clinical development of these vaccines at the outset will assist in advocating for South Africans to be amongst the first in line to access these life-saving vaccines, once they become available.”

The South African NVX-CoV2373 trial

The screening of volunteers for the South African Novavax Covid-19 vaccine trial begins on Monday, 17 August.

To volunteer for this trial, please visit

The Phase 2 NVX-CoV2373 study in South Africa will enroll up to 2 904 volunteers aged 18-64-years-old. The trial will evaluate the vaccine candidate’s safety, immunogenicity, and efficacy [protection against Covid-19].

The randomized, observer-blinded, placebo-controlled Phase 2 clinical trial in South Africa will include two cohorts:

  • One cohort will evaluate the efficacy, safety and immunogenicity of NVX-CoV2373 in approximately 2,650 healthy, HIV-negative adults.
  • The second cohort will evaluate the safety and immunogenicity of NVX-CoV2373 in approximately 240 medically stable, HIV-positive adults.

“This important Phase 2 clinical trial will not only provide additional data on safety and immunogenicity of NVX-CoV2373, it also has the potential to provide an early indication of efficacy, as South Africa is experiencing a surge of Covid-19,” said Stanley C. Erck, President and CEO of Novavax.

The Bill & Melinda Gates Foundation awarded Novavax a $15 million grant towards the Covid-19 vaccine effficacy trial in South Africa.

The South African study is part of a larger, global clinical programme to evaluate NVX-CoV2373, including larger Phase 3 studies with approximately 30 000 participants, to be launched throughout the world.