SA vaccine trial shocked by how many people already had Covid-19
‘We did not anticipate high number of asymptomatic people, which shows how extensive infection rate is’
Almost a fifth of the 474 South Africans screened for SA’s Covid-19 vaccination trial were excluded from participation due to underlying conditions, including untreated hypertension, a lead researcher told Times Select.
Sub-investigator Clare Cutland said of that number, 202 had been enrolled in the trial and vaccinated to date.
She said 35 of the 162 patients enrolled by Monday (21%) tested positive for Covid-19 before receiving the vaccine.
“All of them were asymptomatic on the day of their [nasal] sample collection. Global studies are revealing that many people infected with Covid-19 are either asymptomatic or mildly symptomatic.
“Because of the high numbers of asymptomatic Covid-19 cases enrolled in the trial to date, it means one out of every five participants will have to be excluded from certain planned analyses, which could affect the power of the study.”
She said to avoid this, more participants would need to be enrolled.
Cutland, who is also a scientific coordinator at Wits University’s African Leadership in Vaccinology Expertise, said this was not anticipated.
“It reflects how extensive the infection rate really is in communities.”
Cutland said because of how many people were infected, but asymptomatic, the trial’s protocol had to be amended. This included restructuring screening protocols.
She said trial sites were now testing people during screening for past or current Covid-19 infections.
“We do blood tests for antibodies indicating past infections and nasal swabs, which show current infections. Anyone who has been positive will not be eligible for the trial.”
The participants already enrolled into the trial before this protocol amendment, who were found to be positive on the day of vaccination or who had been infected before vaccination, would remain on the trial, Cutland said.
“However, their data will not be used for some of the analyses.
“Going forward, those who test positive at the time of screening, or who are found to have been positive before screening, will be excluded from the trial.”
She said the protocol amendments had been approved by an ethics committee and all those already screened, but not yet vaccinated, would be rescreened, with new nasal and blood samples taken.
Participants would be enrolled in the trial for a year, with samples regularly taken from them.
Cutland said they were looking for three different results, which included the trial’s safety results, which were expected within the next couple of months; immune response results to the vaccine, which were expected at the end of the year or early next year; and the efficiency of the vaccine.
“The efficiency results are only expected to be known next year.”
So far, so good
It has been two weeks since Junior Mhlongo received a potential Covid-19 vaccine.
“I am really not worried. I have not shown any symptoms and do not feel any different to how I felt before the trial began,” the 24-year-old told Times Select.
Mhlongo is one of 2,000 South Africans from across Gauteng who will take part in a global clinical Covid-19 vaccination trial.
“I am not someone special. I am just doing what I think is right. I see the [Covid-19] deaths on TV. Every day more and more people are dying and I hope to help stop that.
“This week those of us who are involved in this vaccine trial might know if it is starting to work.”
As part of the trial’s safety-protocol requirements, patients are expected to remain in isolation, with medical staff monitoring them.
Patients are injected with a non-replicating version of a common cold virus (adenovirus) - that is unrelated to Covid 19 - and which has been engineered to include the spike protein gene, which stimulates antibody production against the SARS-CoV2 that causes Covid-19.
Once the patient has been injected, samples are taken from them for analysis to determine the efficacy of the potential vaccine.
Mhlongo, who has been in isolation since having the potential vaccine administered, said medical staff had taken blood samples from him twice.
“I last saw them last week Wednesday [July 1]. They were very kind and caring, asking me lots of questions and wanting to know how I was feeling.
“I told them I am fine and don’t feel anything that I should not be feeling.
“This virus is not a joke. I am so tired of people thinking that it is. I don’t understand why people won’t listen and stay at home.
“People are worried about money, but what about life? For me, life is more important than money, because if you die, who will look after your family?”
Targeted by anti-vaxxers
Another test subject, who asked not to be named, said since protests by anti-vaccine supporters outside Johannesburg’s Wits University, he had been scared to tell people he was taking part in the trial.
“If I didn’t have a family and children I would not care about being named, but not now.
“People think because some of us are poor, or come from Diepkloof [Soweto] or other poor areas, we don’t know what we are doing, and that we are allowing people to experiment on us and kill us.
“What they do not understand is that poor people can help and that poor people can also make a difference.”
He said since receiving the potential vaccine he had no adverse effects.
“I was worried. It’s natural to be, but I told myself I would be fine and that God would protect me. I am doing this because I hope, one day, all people will be protected from this virus.”
To date, Covid-19 has killed more than 3,500 people in SA and infected more than 215,000.
The South African Ox1Cov-19 Vaccine VIDA Trial is the first in Africa.
It began two weeks ago with the administration of the potential vaccine to eight Soweto residents, one of whom is Mhlongo, with medical scientists hoping to have results by November.
In SA, the trial is being run from three undisclosed Gauteng medical facilities and involves researchers from Wits University, the SA Medical Research Council (SAMRC), Oxford University in the UK and scientists from Brazil and the US.
- This story has been updated to clarify that patients are not injected with Covid-19 but rather with a non-replicating version of a common cold virus (adenovirus) - that is unrelated to Covid 19 - and which has been engineered to include the spike protein gene, which stimulates antibody production against the SARS-CoV2 that causes Covid-19.