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FILE PHOTO: In this illustration taken on October 31, 2020, vials with a label that reads “COVID-19 / Coronavirus Vaccine / Injection Only” and a medical syringe are seen in front of the Pfizer logo displayed (Photo: REUTERS / Dado Ruvic / Illustration / File photo / Wikipedia)
The head of the South African branch of a key clinical trial of the Covid-19 vaccine is “full of pride” in the participation of the teams in the first investigations showing that the candidate vaccine is more than 90% effective. But it is not clear if the vaccine will be available in South Africa. Adele Baleta informs.
This week’s announcement of a breakthrough in the development of a Covid-19 vaccine is “a massive development,” according to Dr. Essack Mitha, a clinical trial specialist whose team has assisted with clinical trials.
“It is very exciting and the intermediate results are very promising. It leaves me very hopeful as this could pave the way for a vaccine to be developed before the end of the year, ”says Mitha, owner of Newtown Clinical Research in Johannesburg.
Pfizer and BioNTech, a German company, announced this week that their vaccine candidate was successful in preventing the symptomatic disease Covid-19 in the first interim analysis of the phase 3 trial that includes 44,000 people in a variety of countries.
While the news has been widely welcomed and global stock markets soared after the announcement, there has been some caution and criticism. There is consensus that more data is needed, and some commentators have said that announcing the companies through a press release (and not a peer-reviewed publication) is not good scientific practice nor does it help build public confidence in vaccines. .
Will South Africa have access?
Pfizer and BioNtech have said they will have 500 million doses of the vaccine available by the end of December and 1.3 billion doses by early 2021. Several countries have already reached agreements with manufacturers to access the vaccine.
So far, South Africa has not obtained candidate vaccine doses from Pfizer or any other manufacturer.
The country also missed the first deadline to commit to Covax, an initiative co-led by the World Health Organization that aims to ensure that developing countries have access to Covid-19 vaccines.
Health Department spokesman Popo Maja confirmed that South Africa had not concluded any vaccine deals, but added that negotiations with the manufacturers and Covax were ongoing.
Reuters news agency has reported that Botswana made an advance payment to Covax this week, giving it the option of securing more than 940,000 doses of a Covid vaccine in a two-dose regimen for 20% of its population.
Early analysis
Initial analysis of the Pfizer results showed that people who received two injections of the vaccine three weeks apart experienced more than 90% fewer cases of symptomatic Covid-19 than those who received a placebo (a dummy, usually water salty). Researchers have consistently warned that a vaccine can only be 60% to 70% effective.
Pfizer and BioNtech have so far analyzed data from 94 people who developed Covid-19, and the study will close with analysis of data from 164 trial participants who developed the disease. The primary endpoint of the trial is not prevention of SARS-CoV-2 infection, but prevention of a clinically recognizable disease (i.e., Covid-19).
There are still many unanswered questions.
Although there have been no major safety concerns to date, the safety of the vaccine should be continually assessed and this would be included during a Phase 4 study as well as with post-marketing surveillance.
It is not yet known if the vaccine works in the elderly, people with HIV, hepatitis B and C, and people with comorbidities such as diabetes and hypertension.
It is also not yet known whether a vaccinated person with symptoms can spread it to other people. It is also not known if the vaccine protects equally against mild, moderate and severe cases of Covid-19.
The South African arm of the trial includes 800 participants at four sites in Johannesburg, Pretoria, the Western Cape, and Limpopo.
“I am very proud of our teams in South Africa who have come together with this particular protocol,” says Mitha. “It has been very hectic in the last few weeks because the deadlines are short, but things like this make it worth it.”
South Africa joined the trial in late September, a month after the global study began.
Mitha, who has been conducting clinical trials since 2004, says he expected to recruit more than 800 participants.
“We completed our recruitment ahead of schedule in the hope that the company would allow us more patients, but there were delays in our Health Department approving additional numbers, which really limited us. It was sad, because in the end we had queues of people lining up to participate in the study and we had to reject them. “
According to Maja, clinical trials are a regulatory issue over which the national Health Department has no jurisdiction. “It does not give permission to participate in the trial.”
The trial participants received the first dose in late September and the second dose in late October. Mitha believes that some data from the first participants in South Africa were included in the interim data analysis presented this week.
The selection of South Africa as a global host for the study was based on local scientific expertise and capacities, the epidemiology of the disease, and South Africa’s previous experience in conducting clinical trials.
Mitha adds that other factors to include in the trial were that “we have a diverse genetic profile and a high prevalence of HIV, people with hepatitis B and C infection and comorbid diseases such as hypertension and diabetes.”
Cold chain concerns
One of the main concerns is the future distribution of the possible vaccine in low-income countries. The vaccine must be transported and stored at an extreme temperature of minus 80 degrees Celsius.
“This poses a challenge, but there is a flicker of optimism. These types of vaccines can be manipulated. It is likely that in the coming months the vaccine will be modified so that it is more stable at different temperatures ”, explains Mitha.
Pfizer is working to improve cold chain requirements for 2 ° C to 8 ° C, according to STAT news.
The director of the Africa Health Research Institute, Professor Willem Hanekom, says the results are “very exciting” and “encouraging.”
“Vaccine storage is unlikely to have been a priority until now because they first had to see if the vaccine works, but future development will seek to make it accessible in terms of distribution.”
The mRNA vaccine
The Pfizer / BioNTech vaccine is based on the genetic material mRNA (or messenger ribonucleic acid). MRNA vaccines have a piece of genetic material that codes for viral proteins or parts of them. Once inside the cells, the mRNA instructs the cells’ protein factories to make copies of the viral proteins. These then stimulate the immune system to mount a protective immune response.
Hanekom says the interim results are also encouraging for most other vaccine candidates that want to induce similar types of immunity against the spike protein. The Pfizer trial is “a proof of concept that spike protein immunity may be important for protection and therefore we are optimistic that other approaches will work as well.”
Hanekom and Mitha agree that the interesting part of the mRNA vaccine platform, which has never been used before, is that it is cheaper and faster to develop a vaccine than traditional vaccines.
Hanekom says that security data has yet to be comprehensively analyzed.
Commenting on long-lasting immunity, Mitha says that the question of how long immunity lasts can only be determined over a period of time. “Our time frame is to check antibody levels at six months, 12 months and two years. This type of data will emerge as the study progresses. “
Mitha says that while there are floodlights hesitation for the vaccine, “Over 90% of the people I have committed to would accept vaccines. While there may be financial implications and they may not get the shots, the will is there and they want a vaccine. “
The South African arm of the trial will continue to care for patients and ensure that all data is captured for the final results of the study.
“For me, the main problem here was offering our patients the opportunity to participate in the trial and we have realistically offered the vaccine to our patients before it is released globally. That is very exciting for me and my patients are very happy.
“There has also been interest from some other companies to participate in other vaccine studies, so it looks like it will be a very busy 2021,” he says. DM / MC
Adele Baleta is a freelance science writer, WHO Vaccine Safety Communications Advisor, and Internews Pandemic Advisor.
Spotlight last week sent a general list of questions to the national Department of Health about its plans to procure the Covid-19 vaccine. These questions were acknowledged and an extension of time was granted upon request. We will report the responses when we receive them.
- This article was written for Highlight – Public interest health journalism.
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