COVID-19 vaccine results hopeful, but don’t hold your breath
Professor Lucille Blumberg, the deputy director of the National Institute for Communicable Diseases (NICD), is extremely positive about the vaccine tests, but says, “Realistically, we aren’t looking at a vaccine before early next year. That’s the best we can hope for.”
Professor Barry Schoub, emeritus professor in virology at the University of the Witwatersrand (Wits), and the former director of the NICD, says, “We can really talk about a widely available, reasonably cheap and safe vaccine only at the end of next year. That’s assuming all the trials go well. We need to be really careful about health safety as we’re giving a virus to healthy people.”
Nonetheless, Schoub says the preliminary results have been positive. “They have produced the necessary antibodies and minimal side effects. It looks very promising.”
The initial South African vaccine trial is being run at Chris Hani Baragwanath Hospital in Soweto by Shabir Madhi, professor of vaccinology at Wits. This is part of a multinational study that includes South Africa, the United Kingdom, Brazil, and the United States.
While sourcing a vaccine typically takes about a decade, researchers are expediting the process. More than 100 vaccine candidates are being developed. There are, however, four vaccines which are leading the race, says Jeffrey Dorfman, an associate professor of virology at Stellenbosch University.
“Of the four, two are being developed by Moderna and Pfizer BioNTech, and are RNA vaccines,” Dorfman, told the SA Jewish Report. “These vaccines are made up of RNA, which is taken up by cells and directs the body’s own cells to make a protein that the virus uses to get into cells, called the spike protein [that attaches itself to the cells].”
The vaccine that South Africa is testing, according to Blumberg, who participated in Chief Rabbi Dr Warren Goldstein’s webinar on Sunday, is from Astra-Zeneca (in partnership with Oxford University’s Jenner Institute).
“This vaccine is based on a common-cold virus of animal origin. It has been modified so it’s safe. It doesn’t multiply, and is coded to produce the spike protein for the COVID-19 virus,” she says.
“If you inject this vaccine, the body will mount an immune response to it. So, when you are challenged with the virus itself, you already have antibodies. Early studies would support it producing an immune response,” Blumberg says.
Dorfman says vaccine-trial preparation is taking place in Johannesburg and Cape Town, with volunteers being recruited to test the efficacy of the Oxford vaccine.
He believes this vaccine is probably better than the Cansino vaccine because it uses a chimpanzee cold virus. “This is helpful because very, very few people have been previously exposed to it. If a patient who has been vaccinated has already been exposed to the cold virus that is the scaffolding of the vaccine, then that immune response will inhibit the vaccine.
“The cold-virus-based vaccines also have much more data to back up their safety from testing of these other vaccines,” Dorfman says.
The group in South Africa is “highly experienced in testing vaccines, probably the most experienced at this in Africa”, Dorfman says. “The antibody measurement will be done at the laboratory of Professors Lynn Morris and Penny Moore at the NICD, which has been measuring neutralising antibodies for HIV-1 and influenza for years, making this a very experienced choice.”
He says the trials have been approved by authorities within Wits and by the South Africa Health Products Regulatory Agency.
“This is necessary to be sure that study participants aren’t exposed to any undue risk or incentives large enough that might make them overlook risks,” he says.
While no one is sure what the trials will yield, results of initial trails have given hope.
“At this stage, they are close to the best possible results for the four vaccines,” says Dorfman. “The basic idea concerns neutralising antibodies or antibodies that bind to the virus in a way to prevent it from infecting a cell. If a virus can’t infect a cell, it can’t reproduce.
“These antibodies are the most logical thing to look for in a vaccine, and are logically presumed to protect the person vaccinated.”
However, both he and Schoub stress that no one knows if neutralising antibodies will protect people, how long it will be effective, or if other immune responses are needed.
“This will only become clear in the bigger trials now running that will vaccinate larger groups of people and look to see if the vaccinated study participants are less likely to contract COVID-19,” says Dorfman.
“Keep in mind that only something like one in 10 vaccines that go to trial are good enough to be licensed, and none for more difficult diseases such as HIV-1 and malaria.
“Vaccine development usually takes about 10 years,” says Schoub “It goes from proof of concept in a laboratory when an agent is identified, to being developed for animal testing, and only then can clinical trials begin.”
The last leg comprises three phases, he says.
“The first two involve small numbers of human volunteers [about 100], and are aimed at determining the dosage which will elicit an immune response without side effects and whether the vaccine is genetically stable.
“Phase three is when we get to evaluate the efficacy of a candidate vaccine. Typically, it needs a large number of test subjects, so thousands of people are involved. This is where we are right now.”