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- The first results of a Covid vaccine have already been published, and Pfizer and BioNTech reported an efficacy of 90% according to the first data
- Despite its promise, cold chain requirements mean this coup would not be the first choice for countries like South Africa.
- The vaccine must be kept at minus 70 degrees Celsius, well below other vaccines used in South Africa, posing a great challenge for delivery and storage.
It is highly unlikely that the world’s first hope for a Covid-19 vaccine, the jab developed by pharmaceutical companies Pfizer and BioNTech, which shows 90% efficacy in preventing Covid-19 in early results, will be widely available. in South Africa.
This is because the vaccine must be stored in subzero temperatures, minus 70 degrees Celsius, which the country does not have the capacity to do on a large scale. If the injections are kept at temperatures that are too high or too low, they can go bad and be less effective.
In the United States, hospitals in big cities are already “rushing to buy expensive ultra-cold freezers” that cost between R150,000 and R235,000 each, to store injections, for which Pfizer and BioNTech will apply for an emergency license the U.S. regulator, the Food and Drug Administration (FDA), later this month, Statnews reports.
And just three days after the announcement of the first interim results of the BNT162b2 vaccine, the European Union signed an agreement with the manufacturers to supply it with 200 million doses and an option to request an additional 100 million doses, “and deliveries are expected to start by the end of 2020, subject to regulatory approval ”.
But South Africa does not have the ultra-cold freezers needed to store the vaccine, except for a few at large research institutions like the National Institute for Communicable Diseases, says University of Cape Town Vaccines for Africa director Gregory Hussey. .
And, along with less well-off rural hospitals in developed countries, the country is unlikely to be able to afford to buy enough freezers to be able to make the vaccine available in community health centers or clinics, or to pay for the cold chain. . systems needed to maintain vaccines.
Most of the vaccines that are part of the South African immunization program should be kept at temperatures between two and eight degrees Celsius. Therefore, the country’s system, including vaccine transport, storage and monitoring, is not adequate for vaccines that must be kept below freezing temperatures.
And the Pfizer / BioNTech vaccine is not the only Covid-19 pioneer likely to pose a problem for South Africa. The Modern Pharma mRNA-1273 jab, whose first results are likely to be published before the end of the year, should be stored at minus 20 degrees Celsius.
Pfizer / BioNTech and Moderna’s vaccine use mRNA technology. These vaccines use pieces of artificial genetic material known as messenger ribonucleic acid, or mRNA, which instructs our bodies to make proteins, in the form of antibodies and killer cells, to fight SARS-CoV-2, the virus that causes Covid. -19.
But the problem is that these two mRNA vaccines must be kept at extremely low temperatures or they risk being damaged.
And to further complicate matters, mRNA vaccine technology is new: to date, not a single vaccine that uses mRNA messengers has been licensed for human use.
“I don’t know if we could really envision an mRNA vaccine in our current setup,” explains Barry Schoub, chairman of South Africa’s ministerial advisory committee on coronavirus vaccines. “Things can change, but with our current setup, the places where we could actually use it would be so limited that it would be quite a challenge.”
South Africa’s challenge of keeping vaccines fresh
Maintaining a cold chain, where a product must be constantly stored at a low temperature, is important to ensure that vaccines do not degrade or lose their effectiveness. A 2018 article in the magazine Vaccine, showed that although this deterioration did not represent a risk to the safety of the people receiving the vaccine, the jabs offered less protection after being stored at the wrong temperature.
This is a major risk for rural hospitals and clinics or those facilities that lack the proper infrastructure to properly store doses when a Covid vaccine is available, according to Hussey, who is also part of the Covid Vaccine Ministerial Advisory Committee.
Schoub, who is also a virologist and former director of the National Institute for Communicable Diseases, agrees: “You really can’t reliably and sustainably store vaccines at minus 20 degrees Celsius anywhere outside of the biggest cities. Especially if you’re looking in warmer climates like the North Cape or KwaZulu-Natal, even keeping a freezer at minus 20 will be a question mark. “
According to Schoub, Pfizer / BioNTech are considering lyophilized vaccines, in the form of frozen powders to which liquid is then added, that could alleviate the cold chain requirements for jab, because they can be stored between two and eight degrees Celsius. But the timeline for this, he says, is still unclear.
But even without taking into account the additional hurdles that will come from keeping a vaccine well below 0 degrees Celsius, simply regulating the temperature of our existing vaccines is already challenging.
An evaluation of vaccine management in 18 countries by the World Health Organization Regional Office for Africa in 2001 found that “only 47% of the indicators were satisfactorily met for buildings, cold chain equipment and transport to Nacional level”.
In the Western Cape, a 2015 study published in Vaccine found that government-run vaccine supply chains were often unable to adequately handle the temperatures at which vaccines must be stored.
The average temperature of health center refrigerators in the study ranged from 0.9 to 9.2 degrees Celsius, meaning the jabs could have been stored at too low or too high temperatures and suffered damage.
Why does 90% efficiency matter?
Despite the administration challenges of the Pfizer / BioNTech vaccine, its potential efficacy of 90% has clinicians and scientists excited, most of whom expected a much lower efficiency.
Although it’s only the initial data that could still change as the trial progresses, this kind of efficacy puts the jab in the same category as the world’s most effective vaccines, such as the measles vaccine.
Schoub explains: “If it turns out to be true, then it is a big step forward, but at this stage it is very difficult to assess how accurate that figure is because it is still early in the test.”
A higher efficacy rate means that the jab can offer more protection to a population. This is important when it comes to the role of a vaccine in offering immunity to a community.
If only half of the people who receive a vaccine are to be protected, a much larger portion of the population needs to be vaccinated for it to make a difference and adequately contain an outbreak.
With herd immunity as the end goal, where a sufficient number of the population is protected or resistant to the virus and stops spreading, measles vaccine, which is 97% effective in preventing measles, is often considered the ideal.
But so far, scientists have been skeptical that we can reach the same level when it comes to Covid-19.
As Schoub explains, it was speculated that a Covid vaccine would be unlikely to offer the same level of protection as the measles vaccine due to the differences between the two diseases. While both are transmitted similarly, through coughing or sneezing, they fundamentally differ in how they affect a person’s body.
Measles is a systemic disease, meaning that it affects the entire body, while Covid is initially a lung disease that primarily targets the lungs. In that sense, Covid is more similar to influenza, which is what has been used as the gold standard when it comes to the efficacy of the vaccine, says Schoub.
The distinction in how the disease works is important, because it influences the type of immune response: measles requires the production of antibodies in the blood to fight the measles virus, and influenza requires a more complicated immune response through antibodies in the respiratory secretions.
The type of immune response needed to fight the flu is difficult to achieve through vaccines, and most flu shots only offer about a 60% chance of protection against infection.
Therefore, most Covid vaccine trials are designed to be around 60% effective in a vaccine candidate, explained the director of the US government’s National Institute of Allergy and Infectious Diseases, Anthony Fauci, in a seminar. Medical Brief website in October.
But regardless of whether the Pfizer / BioNTech candidate is right for South Africa, the issue of delivering a vaccine is something we need to start working on now, says Hussey.
He concludes: “There is a huge cost involved in delivering a vaccine, the World Health Organization has estimated that the cost of delivering the vaccines could be up to two or three times higher than the cost of the vaccines alone. .
“There are also the added operational costs of running immunization campaigns during the Covid-19 pandemic. We have to make sure that the facilities, the staff administering the vaccines, and the vaccine recipients are kept ‘Covid safe.’ something that we must take into account our planning. “
And while South Africa only hopes to receive enough Covid vaccines for around 5% of its population by next year, and a big rollout for the general public is likely to only come in the next two years, Hussey cautions: “I think getting Vaccine is a simple thing. Getting the vaccine to the people who need it is the challenge and we don’t have a great track record even for getting routine vaccines to the communities that need them most.
* This story was produced by the Visit the Center for Health Journalism. Sign up for the Newsletter.
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