South African volunteers are about to join the first Covid-19 vaccine trial to be conducted in the country. Called the South African Ox1Cov-19 Vaccine VIDA-trial, it’s being led by Wits University researchers and marks a first for the continent. The trials are being conducted in collaboration with the University of Oxford and the Oxford Jenner Institute. 

The vaccine candidate being trialled is one of an unprecedented number of 268 other candidate vaccines currently being researched and tested round the world. 

Countering vaccine nationalism?

South Africa’s collaboration is considered essential to fast-track a path to immunisation against the virus that’s already killed close to 500,000 worldwide. It’s also a collaboration that it is hoped will ensure the country and Africa are not relegated to the back of the queue if and when a vaccine goes into production.

Equitable access to a vaccine and establishing safeguards against muscling out poorer nations in the scramble for surviving Covid-19 remain at the level of “global debate”. There are no concrete agreements or protocols in place to ensure people in poor or developing countries will have access. 

Professor Helen Rees, executive director of the Wits Reproductive Health and HIV Institute in Johannesburg, co-director of the Wits African Local Initiative for Vaccinology Expertise (Alive) and advisory board member of CEPI (Coalition for Epidemic Preparedness Innovation) was part of the panel that announced the launch of the South African trial on Tuesday.

“Early vaccine trials were coming from more developed economies such as the US, UK and China, which led to concerns that we need vaccines that are tried and tested for safety and efficacy on all populations from across the world,” said Rees. “Already we are seeing a rise in ‘vaccine nationalism’ and vaccine production being ring-fenced for richer countries. It cannot be a case of ‘my country only’ and ‘my country first’,” she said. 

“By participating in the trials we are saying that we want to be part of this scientific endeavour and we also want to be able to say that because we have helped in developing a vaccine, we want to ensure that people from the country and the region will have access to the vaccine.”

Rees also warned that even when an effective vaccine is developed there will not be enough to meet the needs of the world’s billions all at the same time.

“We do not need a potential replay of how access to antiretroviral drugs for Africa was blocked, which is why the question of who gets priority in accessing a vaccine is so important,” she said.

‘Landmark moment’

“This is a landmark moment for South Africa and Africa at this stage of the Covid-19 pandemic. As we enter winter in South Africa and pressure increases on public hospitals, now more than ever we need a vaccine to prevent infection by Covid-19,” said Shabir Madhi, Professor of Vaccinology at Wits and director of the South Africa Medical Research Council (SAMRC) Vaccines and Infectious Diseases Analytics Research Unit (VIDA). 

Madhi, who will lead the trial, said that there will be 2,000 participants. A list of frequently asked questions (FAQ) provided to media explained that half of the participants will receive injections of the candidate vaccine and the other half (the control group) will receive a placebo (normal saline). 

“The random grouping of participants to receive either the vaccine or the placebo helps researchers understand participants’ response to ChAdOx1-Cov19, its safety, and whether the vaccine protects against Covid-19,” the FAQ explained.

As Madhi explained, the design of the study is actually a bit more complicated than just a treatment and a control group. While, for example,  1,950 of the participants will be HIV negative, they will also seek to recruit 50 people living with HIV to the trial to test the safety of the vaccine in this group. There will also be some differences in dosing between subgroups. (You can see how the groups are divided on the trial’s ClinicalTrials.gov page.)

According to the FAQ the objective of the trial is to investigate whether the ChAdOx1-Cov19 vaccine will protect against Covid-19, doesn’t cause unacceptable side effects, and if it induces satisfactory immune responses. 

Apart from sites in Gauteng, the study should also be under way at two sites in the Western Cape by early July. The FAQ explained that “the study is being undertaken in urban metropoles where the risk of SARS-CoV2 infection is high, and which are likely to be Covid-19 hotspots.” The 2,000 participants in South Africa will join what will be 10,000 participants in the United Kingdom and 5 000 people in Brazil who are receiving the same vaccine in trials there.

Madhi says at the earliest they can expect results by the end of 2020, although the timing of results will depend on how many people in the trial contract SARS-CoV-2. Broadly speaking, the more study participants contract the virus, the sooner results will be available.

He added that production of an actual vaccine, however, is a long way off with a possible production timeline only by the end of the last quarter of 2021. He stressed that non-pharmaceutical interventions of mask wearing, social distancing and good hand hygiene remain the best interim intervention.

Two more vaccine trials anticipated in SA

Professor Glenda Gray, CEO and president of the Medical Research Council (MRC), said the council is funding the vaccine trial to the tune of R10-million, with additional funding coming from the Bill and Melinda Gates Foundation. 

She added that the MRC expects to be supporting another two vaccine trials for Covid-19 later in 2020 as part of developing local solutions and innovation to fight the virus. Gray said multiple successful vaccines will help in making widescale and rapid immunisation a reality.

Dr Sandile Buthelezi, newly appointed Director General in the Department of Health, said the vaccine trial has the department’s full support and comes at the milestone of 100,000 confirmed cases of Covid-19 in South Africa, signalling that there is no more time to waste.

How the vaccine works

The ChAdOx1 nCoV-19 vaccine uses non-replicating, genetically engineered chimpanzee adenovirus as a vector, or molecular carrier, that has genetic material called spike glycoprotein from the surface of SARS-CoV-2 added to it. This is injected into trial participants. It’s the spike protein binding to an enzyme called ACE2 receptors in human cells that allows the virus to take hold. 

“The adenovirus is genetically sequenced with the code of spike protein found on the surface of coronavirus. When this is injected into the participant the spike protein is presented to the immune cells, triggering an immune response of antibodies being produced. The antibodies attach to the spike protein and prevent the virus from attacking the human cells. When there is a saturation of antibodies we are protected from disease,” Mahdi said. DM/MC

*This article was produced by Spotlight – health journalism in the public interest. 

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