The number of Covid-19 cases continues to rise in many countries around the world, and vaccine development is widely seen as the last hope for a return to normality.
Currently, there are more than 100 vaccines in development, but only six of these studies involve humans, said Professor Shabir Madhi, professor of vaccinology at the University of the Witwatersrand (Wits) in Johannesburg, and director of the South Africa Medical Research Council (SAMRC) vaccines and infectious diseases analytics research unit (VIDA), during a press conference hosted by Wits today. Madhi is also leading the South African Ox1Cov-19 Vaccine VIDA-Trial.
Wits is collaborating with the University of Oxford and the Oxford Jenner Institute on the South African trial for the vaccine, known as the ChAdOx1-Cov19 vaccine.
The study will begin tomorrow, and here’s what it involves.
Who qualified for enrollment
Inclusion criteria for study volunteers involved a number of factors, said Madhi, including:
Healthy adults aged 18–65 yearsProvision of written informed consent (includes an assessment of understanding of the study)Documented result of not being infected with HIV. Able and willing to comply with all study requirementsFor females only: a willingness to practise continuous effective contraception and a negative pregnancy testFor Groups-3 only (i.e. HIV-infected): need to have been on antiretroviral treatment for at least three months with HIV-1 viral load being <1 000 copies/ml within two weeks of randomisationPeople who were excluded from participating in the study include pregnant and breastfeeding women, as well as those who expressed a willingness to become pregnant during the course of the study.
Those with a history of severe disease, substance abuse, chronic respiratory (including asthma) or cardiovascular illness, were also excluded, as well as people who presented with an onset of cough or shortness of breath within the past 30 days. Madhi further expressed that a key goal of the study is to evaluate the safety of the vaccine in people with and without HIV.
Study to consist of three groups
The study has enrolled 2 000 volunteers, 50 of whom will be people living with HIV. Group 1, which will include 50 people living without HIV, will begin tomorrow.
All volunteers should not have tested positive for Covid-19 and should not be pregnant or breast-feeding, nor have participated in any related trial in the past. Written informed consent to participate in the trial was provided by all volunteers, and they will remain part of the trial for approximately one year.
Course of the study
The anticipated study timeline will include the first participant being enrolled this week, with a complete enrollment taking place across multiple sites by mid-August of this year, said Madhi.
There will be planned follow-ups, up to 12 months after vaccination and participants will have fortnightly appointments to assess for any respiratory illness. They will also be investigated for Covid-19 in the event that they fulfil criteria that indicate illness.
An ongoing evaluation of safety by the Independent Data and Safety Management Committee (for UK, Brazil and South African studies) will also be part of the study, Madhi added.
For now, until a vaccine becomes available, we have to continue protecting ourselves via non-pharmaceutical interventions such as basic hygiene practices like regular hand-washing, wearing face masks and maintaining physical distancing.
The trial is one of three currently being run
South Africa, the UK and Brazil are part of the three studies related to this vaccine that are currently underway. The study in the UK is ongoing and has already enrolled more than 4 000 participants, and an even larger study of 10 000 is due to start soon. Brazil’s study is underway and has enrolled approximately 5 000 participants.
If successful, when will the vaccine be rolled out?
“I think the reality is that our best-case scenario is that we would be able to have an answer for this particular vaccine by the end of the year. It might take longer, depending on how quickly we accrue outcome cases,” said Madhi, adding:
“But even after that has been completed, it doesn’t mean that a vaccine becomes available immediately. There needs to be manufacturing plants that are set up, which is currently being done. And then the product that comes out of those manufacturing facilities needs to be evaluated in terms of ensuring that it's similar to the product that was evaluated.
“So the best-case scenario in terms of when it might become available would probably be in the third quarter of 2021.”
Professor Helen Rees, executive director of the Wits Reproductive Health and HIV Institute at Wits also weighed in: “Even if we have successful vaccines through clinical trials, we will not have enough vaccines for everyone in the world by the end of 2021. We’re talking billions and billions of doses.
“So, we are going to have to look at prioritisation, and there is an entire global effort at the moment which is looking at how and who we prioritise.”
Professor Glenda Gray, member of the Ministerial Advisory Committee (MAC) and chairperson of the South African Medical Research Council (SAMRC) also commented:
“We hope not only one vaccine will be successful. We need five or six vaccines that are successful to ensure we can scale up to the billions of doses we need at global level. It’s also critical that we [South Africa] are involved in efficacy studies that get us first in the queue for access afterwards as well.”
Under what circumstances would the trial be suspended or terminated?
Throughout these studies, both in the UK and Brazil as well, the Independent Data and Safety Management Committee reviews what’s happening in the studies, said Madhi. “And if there’s any concern on their part… the study would be terminated immediately.”
Apart from a safety issue, the study can also be prematurely terminated in the following instance, added Madhi:
“If we find a huge number of people that are infected over a short period of time, we can then analyse whether the vaccine works or not. So if we reach 42 cases very rapidly, without completely having enrolled the 2 000 individuals, as an example, we would then already be able to see whether a vaccine works or not and at that point we will stop enrolling further participants into the study.”