• In early results from a human trial, Moderna’s Covid-19 vaccine candidate was shown to be 94.5% effective.
• Scientists say from the detailed findings released, it may have the edge over another candidate which also shows huge promise.
• Approval for this type of vaccine – an mRNA vaccine – has never been granted before, but the early results are a step in the right direction.

Drugmaker Moderna announced on Monday that its Covid-19 vaccine candidate, named mRNA-1273, was 94.5% effective, based on an early look at the results from its 30 000-person ongoing clinical trial.

The news arrived not long after similar results announced by Pfizer last week, and add to growing confidence that vaccines will help fight the pandemic and might be the best chance for the world to return to normal.

Participants in the trial were randomly given a two-dose regimen of either Moderna’s experimental shot or placebo (saltwater) injections. The company’s announcement states that their first interim analysis was based on the first 95 participants to develop Covid-19.

According to the data, there were 11 cases of severe Covid-19 in the trial, but none happened in participants who were immunised.

Moderna says its next step is to seek regulatory approval in the coming weeks for the use of the vaccine in the US. It expects to have 20 million doses available in the country and “remains on track to manufacture 500 million to 1 billion doses globally in 2021”.

What scientists are saying

Professor Thomas Scriba, deputy director of immunology and laboratory director at the South African Tuberculosis Vaccine Initiative, University of Cape Town, told Health24 Moderna’s results are very similar to that of Pfizer’s, and echoed his previous comments on the latter’s vaccine candidate.

“This is clearly an important and very positive step in a chain of many steps that need to be taken before vaccine vials are available in pharmacies and clinics.

“It is great that two vaccine candidates have shown such high levels of efficacy in interim analyses because the burden of proof from two independent sources is growing. Of course, the same limitations raised in my previous comments still stand – these are results shared is a press statement from a very short period after vaccination.

“The news that the mRNA-1273 Covid-19 vaccine candidate by Moderna is stable for 30 days at 2-8 degrees Celsius and for up to 6 months at -20 degrees Celsius is very important and good news, since these are the kind of transport and storage conditions required for many existing medical products (so they are already in place in many settings).

“Distribution and delivery of a vaccine to those who need it will be easier to achieve under these conditions,” Scriba said.

Some experts contacted by Reuters raised the point that the findings reported on Monday with the Moderna vaccine candidate are more detailed.

Professor Bodo Plachter, deputy director of the Institute of Virology at Mainz University Teaching Hospital in Germany, said: “Moderna has the advantage (over Pfizer) that they can already provide detailed findings on aspects such as severe disease, age and side effects.

“The question remains: What will protection look like after three, six or 12 months. It is fair to assume that it will last at least a year but we can’t be sure at this point.

“The side effects are within a range that would be expected of many other vaccines, such as shingles vaccine Shingrix.”

The severe disease aspect was echoed by Eleanor Riley, professor of immunology and infectious disease at the University of Edinburgh.

She told Reuters: “Although the numbers are small, this trial also gives an indication that vaccination is effective in older and BAME individuals and prevents severe disease, all of which are key to allowing the world to start opening up again.

“The absolute prerequisite for a Covid-19 vaccine is that it stops people becoming ill enough to require hospital treatment and stops people dying. The preliminary data reported here suggest that this vaccine – and by extension, the Pfizer/BioNtech vaccine – will achieve this goal.

“The safety data also look promising. The side effects of vaccination appear to be in line with those typically seen for other adult vaccinations, including the seasonal influenza vaccination which is administered in many millions of doses every year.

“One important unknown is whether this vaccine, or any of the vaccines currently in trials, prevents disease transmission.

“It is likely that vaccines that prevent symptomatic disease will reduce the duration and level of infectiousness, and thus reduce transmission, but we don’t yet know if this effect will be large enough to make any meaningful difference to the spread of the virus within communities.

“But, overall, this is excellent news. Having more than one source of an effective vaccine will increase the global supply and, with luck, help us all to get back to something like normal sometime in 2021.”

Very good news

Most scientists agreed that the news was encouraging, especially on the back of the Pfizer announcement last week.

Professor Trudie Lang said: “It is very good news indeed to see another vaccine coming through with similar efficacy results as were reported last week from Pfizer. This is also an interim analysis, which means that there were enough cases within the vaccinated volunteers to give statistical significance and allow the team to break the blind to determine who had the active vaccine and who had placebo.

“Here they found that of 95 cases of Covid, 90 had received the placebo and five the active vaccine. These early results suggest that there was a representation across different age groups and diverse communities in the protected group. This is really encouraging and it further demonstrates that a vaccine for Covid is a real probability and that having more than one supplier should help assure better and more equitable global availability.

“This vaccine is also an mRNA vaccine, so many of the same questions remain as we have been discussing with the Pfizer vaccine and these will be looked at carefully by the regulators.”

Professor Lang is the director of The Global Health Network, Nuffield Department of Medicine, at the University of Oxford.

Much more data needed

“This announcement from Moderna is a further encouragement that vaccines will be found to not only have an acceptable efficacy, but an efficacy that is much greater than we had anticipated. This press release is more specific than that of others, in that it confirms the numbers in each group, which was able to be guessed at but to have it confirmed is helpful,” Professor Stephen Evans told Reuters.

Evans, professor of pharmacoepidemiology at the London School of Hygiene and Tropical Medicine, added: “The range of minor adverse effects reported are unsurprising and typical of almost any vaccine. These reactions tend to be local to where the injection was given and are rarely long-lasting or severe.

“Although they reported efficacy being over 94%, there is statistical uncertainty in this; but based on these data, the likely efficacy will be better than 85% which would be greater than most scientists would have expected.

“This is the first study to report on severe cases and, while uncertainty remains, the finding of no severe cases with the vaccine and 11 cases with placebo is very strong evidence that the vaccine prevents severe as well as mild disease. It is likely that convincing evidence in respect to deaths will probably only be obtained when the vaccine is in use.

“A wide range of people with illnesses and from minority groups were included in the trials as well as substantial numbers of older patients. We will need much more data and a full report or publication to see if the benefit is consistent across all groups, notably the elderly, but this is definitely encouraging progress.”

Peter Openshaw, professor of experimental medicine at Imperial College London, said more complete details were needed but the announcement added to a general feeling of optimism.

“This news from Moderna is tremendously exciting and considerably boosts optimism that we will have a choice of good vaccines in the next few months.

“This latest press release is based on a study of 30 000 US adults, including many high-risk or elderly persons. This gives us confidence that the results are relevant in the people who are most at risk of Covid-19 and in most need of the vaccines.

“Moderna have also announced that the vaccine can be kept in a conventional freezer (-20 degrees Celsius) for up to 6 months, and that once thawed the vaccine can be kept for up to 30 days at standard refrigerator (2 to 8 degrees centigrade). This makes the vaccine much easier to deliver.

“In terms of side effects, news is also quite good. The first dose caused injection site pain in about 3% of people; the second dose was associated with transient generalised symptoms in about 10% of people with fatigue, muscle aches and flu-like symptoms.

“This seems to indicate that they got the dose about right with acceptable adverse events. These effects are what we would expect with a vaccine that is working and inducing a good immune response.

“We need more complete details than we have in this press release, but this announcement adds to the general feeling of optimism about vaccines for Covid-19. What we still don’t know is how long any protective immunity may last. For that, we will need to wait.”

Pfizer first to announce 90%-plus efficacy

Last week, drug maker Pfizer said data from their Phase 3 experimental Covid-19 vaccine, BNT162b2, showed it was 90% effective in preventing infections in volunteers, Health24 reported.

The company and its collaborator, BioNTech, stated no serious safety concerns were found during their large-scale global clinical trials, and they expected to seek US authorisation this month for emergency use of the vaccine.

The data released was based on global data that included the trial site in South Africa, a Pfizer spokesperson told Health24.

“We are pleased to share that the trial in South Africa is going as planned, having already completed recruitment of participants across four sites in Gauteng, Limpopo and the Western Cape,” the company said.

While there are still some unanswered questions, such as how long the vaccine will provide protection, international scientists have welcomed the news saying it “is an excellent result for a first generation vaccine”.

mRNA vaccines

Moderna and Pfizer’s vaccines both use messenger RNA, or mRNA, technology that is designed to trigger an immune response without using pathogens, such as actual virus particles.

This is done by injecting part of the coronavirus’ genetic code into the body, which then starts making viral proteins (but not the whole virus).

Should the person who received the vaccine encounter the virus, their antibodies and T-cells (which acts as “natural killers”) will therefore be triggered to fight it, thanks to the viral proteins which trained the body’s immune system to attack the virus.

Moderna explains that mRNA medicines essentially “instruct a patient’s own cells to produce proteins that could prevent, treat or cure disease”.

mRNA vaccines still need to be approved

While many studies of mRNA vaccines have taken place, none have been approved before – but the promising early results from Phase 3 trials for both candidates, as well as both being above 90% effective, put them in a good position.

“If mRNA vaccines against Covid-19 gain regulatory approval, this will be a huge validation of the RNA vaccine production platform technology,” Zoltan Kis, a research associate at The Future Vaccine Manufacturing hub, at Imperial College in London, told Reuters.

“Using this technology, vaccine candidates can be produced substantially faster in the future to combat virtually any infectious disease, by producing vaccines against both existing pathogens and future, currently unknown pathogens.

“Vaccine candidates can be produced against virtually any disease, because this is a platform technology, meaning that the production process, the purification processes and the formulation processes can remain the same no matter what vaccine or vaccine candidate is produced.

“This is a huge advantage in terms of the speed at which vaccine candidates can be developed and produced in the future.

“In the case of conventional vaccine production technologies, each vaccine required the development of a new production process, whereas in the case of the RNA vaccine production platform technology one process can produce vaccines and vaccine candidates against virtually any disease.”

What’s next?

This is still early data as both Pfizer and Moderna announced their trial findings in news releases. Therefore, as Scriba explained, detailed data that will allow outside experts to evaluate their claims (peer-reviewed journals) have yet to occur, so the results cannot be considered conclusive.

More than this, the trials are still ongoing and additional data may affect results.

Logistical challenges

If and when a vaccine becomes available to the public, there are many logistical issues to consider.

Scriba previously explained that once a vaccine is licenced for human use by regulators, it would need to be manufactured in large volumes, and distribution networks needed to be established and vaccination programmes would have to be put in place to deliver the vaccine to those who needed it.

“These are all non-trivial endeavours. We have had highly efficacious vaccines for a number of deadly diseases for decades and yet these diseases are still causing many deaths and cases of disease because these vaccines do not reach all those who need them.

“This result is clearly an important and very positive first step in a chain of many steps that need to be taken before vaccine vials are available in pharmacies and clinics,” Scriba said.

Additional reporting by Bhekisisa also notes that ensuring that a potential Covid-19 vaccine gets to people who need it – and is effective once they get it – will be challenging in the case of Pfizer’s vaccine, for example, especially for countries like South Africa. 

This is because Pfizer’s vaccine needs to be stored below freezing temperatures (minus 70 degrees Celsius).

Moderna said its candidate could be stored at a standard temperature of between two and eight degrees Celsius for up to 30 days – compared to its shelf life of six months when kept frozen. Despite this revised storage temperature, the jab still needs to be shipped and transported at minus 20 degrees Celsius.

Director of Vaccines for Africa at the University of Cape Town, Gregory Hussey, told Bhekisisa that except for a few of the ultra-cold freezers at large research institutions, such as the National Institute for Communicable Diseases (NICD), SA is unlikely to be able to afford to buy enough of these freezers (which cost between R150 000 and R235 000 each) to be able to make the vaccine available at community health centres or clinics, or pay for the cold chain systems that are necessary to maintain the vaccines.

South Africa has also not yet managed to secure any doses of candidate vaccines from Pfizer or any other manufacturer, Spotlight recently reported, adding that the country also missed the first deadline to commit to COVAX – an initiative co-lead by the World Health Organisation that aims to ensure developing countries get access to Covid-19 vaccines.

However, spokesman for the Department of Health, Popo Maja, confirmed to Spotlight that although SA had not concluded any vaccine deal, negotiations with manufacturers and COVAX are underway.

What about other vaccines?

While Pfizer and Moderna were the first to announce early results on large clinical trials, the World Health Organization’s latest draft landscape of Covid-19 vaccine candidates, dated 12 November, indicates that there are over 40 other candidates in the earlier stages of testing.

Another frontrunner is Johnson & Johnson’s Ad26.COV2.S vaccine, which has already commenced its Phase 3 ENSEMBLE trial.

The company announced on Monday that it launched a new late-stage trial in Britain to test a two-dose regimen of their experimental vaccine among thousands of volunteers, Reuters reported.

This trial will run in parallel with its 60 000-person global trial of a single shot of the vaccine, which was launched in September, and is also currently being trialled in South Africa.

*Additional reporting by Reuters, Bhekisisa, and Spotlight.

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^{Image: Getty/Tetra Images}

Compiled by Zakiyah Ebrahim and Bevan Lakay

• Face masks are strongly recommended to prevent the transmission of the coronavirus 
• However, a recent study showed that masks with exhalation valves do not slow the spread of the virus
• The researcher hopes the evidence will encourage people to wear face masks without valves

The Covid-19 pandemic has brought in its wake the compulsory use of face masks as they help to limit the spread of SARS-CoV-2.

Masks with exhalation valves, however, do not slow the spread of the virus, a researcher from the National Institute of Standards and Technology (NIST) has found.

The videos, which show airflow patterns through masks with and without exhalation valves, were created by NIST research engineer Matthew Staymates and were published, along with an accompanying research article, in the journal Physics of Fluids.

“When you compare the videos side by side, the difference is striking,” Staymates said in a news release by NIST.

“These videos show how the valves allow air to leave the mask without filtering it, which defeats the purpose of the mask.”

What is the purpose of masks with exhalation valves?

Exhalation valves make breathing more comfortable for the wearer. This type of mask is commonly worn by construction workers exposed to huge amounts of dust, or by hospital workers.

However, in the context of the pandemic, the Centers for Disease Control and Prevention (CDC) advises people to wear face masks that protect people other than the wearer. This is especially important for those who don’t display symptoms, as studies have consistently shown how asymptomatic cases are driving the spread of the virus.

“I don’t wear a mask to protect myself. I wear it to protect my neighbour, because I might be asymptomatic and spread the virus without even knowing it,” Staymates said. “But if I’m wearing a mask with a valve on it, I’m not helping.”

Staymates, who is an expert in flow visualisation techniques (which involves capturing the movement of air on camera), recently turned his expertise toward face masks to help develop novel ways to measure and improve their performance.

How the study was done

Staymates created two videos using different flow visualisation techniques. The first video used a schlieren imaging system, which causes differences in air density to show up on camera as patterns of shadow and light.

This video only shows the movement of the air itself, not the movement of exhaled droplets in the air.

On the left in this video, Staymates can be seen wearing an N95 respirator mask with a valve. This mask allows exhaled air to stream into the environment unfiltered.

On the right, there is no valve, and the air passes through the mask, which filters out most of the droplets.

The second video

Staymates created the second video using a light-scattering technique.

For this video, he built an apparatus that emits air at the same velocity and tempo as a resting adult. He then connected the device to a mannequin.

In contrast to the schlieren video, the video shows the movement of droplets in the air. On the left, droplets can be seen to escape unfiltered through the valve of an N95 mask.

In the middle, there is no valve and no breath is visible because the mask has filtered out the droplets. On the right, no mask is worn.

Staymates explained that using a mannequin and a mechanical breathing apparatus allowed him to observe airflow patterns while holding steady the breathing rate, air pressure and other variables.

More than one type of valve mask on the market

Staymates cautioned that different types of valved masks are available and may exhibit different results, and that his study involved only one type of this mask.

He also explained that masks that do not include valves, but that are not tight-fitting will allow some air to escape around the mask rather than filtering through it, which can also compromise the performance of the mask.

However, the main effect of valves is visible in the videos of this study, and Staymates hopes it will help people to understand why face masks meant to slow the spread of the new coronavirus should not have valves.

^{Image: Getty/Svetlana-Cherruty}

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Compiled by Zakiyah Ebrahim

• Recently published research reveals yet another reason why Covid-19 seems to spare young children
• In the study, researchers found that children have lower levels of an enzyme that the virus needs to invade cells in the lung
• Drugs that block the enzyme are currently being tested for Covid-19 treatment

Experts have found that children are mostly spared from the effects of Covid-19 – caused by SARS-CoV-2 – and if infected, often present with only mild symptoms.

Some studies have suggested that children’s lung physiology and immune function could serve as protection, while others have suggested that their blood vessels are better able to withstand a viral attack.

In a newly published study, a team of researchers from Vanderbilt University Medical Center (VUMC) in Nashville, Tennessee and their colleagues found another key reason why Covid-19 spares younger children.

According to their findings, published in the Journal of Clinical Investigation, children have lower levels of an enzyme (or co-receptor) that SARS-CoV-2 needs to invade airway epithelial cells in the lungs.

“Our study provides a biologic rationale for why particularly infants and very young children seem to be less likely to either get infected or to have severe disease symptoms,” Jennifer Sucre, MD, assistant professor of Pediatrics (Neonatology), who led the research with Jonathan Kropski, MD, assistant professor of Medicine, said in a news release published in May, when the study was posted online by the preprint server bioRxiv.

The results also support existing efforts to block the enzyme to potentially treat or prevent Covid-19 in older people, the authors noted.

TMPRSS2’s role in shielding children

The enzyme, type II transmembrane serine protease (TMPRSS2), plays a critical role in SARS-CoV-2 infection, in that it enables the virus to fuse into the cell membrane and “break into” the cell, ultimately hijacking the cell’s genetic material to make copies of its RNA.

Sucre and Kropski considered whether TMPRSS2 plays a role in severe Covid-19 cases observed in older people compared to children.

“Our research has always focused on understanding lung development and how infant lungs differ from adult lungs in their vulnerability to injury,” Sucre said. “In this study, we actually took the opposite approach, and were able to see how the developing lung by its differences is protected from SARS-CoV-2 infection.”

Using a technique called single-cell RNA-sequencing, the research team then built a dataset on lung development in mice, which can detect the expression of genes in individual cells of tissues, such as the lung.

Through this method, they were able to track the expression of genes known to be involved in the body’s response to Covid-19 over time.

More TMPRSS2 found in older adults

They found that while the gene for angiotensin-converting enzyme 2s, called ACE2 (the receptors that allow the virus to enter the body’s cells) was expressed at low levels in the lungs of mice. “TMPRSS2 stood out as having a really striking trajectory of increased expression during development,” Schuler said.

Together with VUMC pathologists, the researchers obtained and analysed human lung specimens collected from donors of different ages, and confirmed a similar trajectory in TMPRSS2 expression to what they’d found in mice.

“What we found is that expression of (TMPRSS2) goes up significantly with ageing, and we see that at the level of the gene and at the level of the protein,” Sucre said.

“We see a lot more TMPRSS2 in older individuals, in both humans and mice.”

Enzyme also linked to prostate cancer

The researchers wrote that TMPRSS2 is also well known for its role in the development of prostate cancer.

Drugs that block the enzyme, and which have already been approved for the treatment of advanced prostate cancer, are currently being tested clinically as potential treatments for Covid-19 as well.

“We do think TMPRSS2 could be an attractive target both in treatment and potentially as a prophylaxis (preventing infection) for people at high risk of Covid exposure,” Sucre said.

READ | Children are more resilient against Covid-19, study shows

READ | A common Covid-19 virus mutation may make it more susceptible to vaccines

READ | More scientific reasons why children are largely sheltered from Covid-19

^{Image: Getty/Volanthevist}

Compiled by Zakiyah Ebrahim

A combination of innate differences and diet-induced changes to the reward system may predispose some mice to overeat, according to research recently published in JNeurosci.

For the first time, a medication has impacted heart muscle thickness and function for patients with the most common inherited heart condition, rather than simply addressing their symptoms.

Fossil bones collected in the early 1990s on Henderson Island, part of the Pitcairn Group, have revealed a new species of Polynesian sandpiper.

• The first results for a Covid vaccine are out, with Pfizer and BioNTech reporting 90% efficacy and Moderna reporting almost 95% efficacy based on early data
• Despite its promise, cold chain requirements mean this jab wouldn’t be the first choice for countries like South Africa
• The vaccine needs to be kept at minus 70 degrees Celsius, well below other vaccines used in South Africa, which poses a huge challenge to its delivery and storage

The world’s first hope for a Covid-19 vaccine – the jab developed by drug companies Pfizer and BioNTech, showing 90% efficacy in preventing Covid-19 in early results, and Moderna’s candidate showing almost 95% efficacy – is highly unlikely to become widely available in South Africa.

This is because Pfizer’s vaccine needs to be stored below freezing temperatures – at minus 70 degrees Celsius — that the country doesn’t have the capacity to do on a large scale. If the shots are kept at temperatures too high or too low, they can spoil and become less effective.

In the United States, large city hospitals are already “rushing to buy the expensive ultra-cold freezers” that cost between R150 000 and R235 000 each, to store the shots, for which Pfizer and BioNTech will apply for an emergency license from the US regulator, the Food and Drug Administration (FDA), later this month, Statnews reports.

And just three days after the announcement of the BNT162b2 vaccine’s first interim results, 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, “with deliveries anticipated to start by the end of 2020, subject to regulatory approval”.

But South Africa doesn’t have the required ultra-cold freezers to store the vaccine – except for a few at large research institutions such as the National Institute for Communicable Diseases, says director of Vaccines for Africa at the University of Cape Town, 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 of the freezers to be able to make the vaccine available at community health centres or clinics, or pay for the cold chain systems that are necessary to maintain the vaccines.

Most vaccines that are part of South Africa’s immunisation programme have to be kept at temperatures between two and eight degrees Celsius. The country’s system – including vaccine transportation, storage, and monitoring – is therefore not suitable for vaccines that need to be kept below freezing temperatures.

And the Pfizer/BioNTech vaccine is not the only Covid-19 frontrunner that is likely to pose a problem to South Africa. The biotechnology company, Moderna’s mRNA-1273 jab, which released its first results on Monday, needs to be stored at minus 20 degrees Celsius.

Although, the pharmaceutical company released new data on Monday showing that their candidate could be stored at a standard temperature of between two and eight degrees Celsius for up to 30 days – compared to its shelf life of six months when kept frozen. Despite this revised storage temperature, the jab still needs to be shipped and transported at minus 20 degrees Celsius.

Pfizer/BioNTech and Moderna’s vaccine both use mRNA technology. Such vaccines use pieces of man-made genetic material known as messenger ribonucleic acid, or mRNA, that instructs our bodies to produce proteins, in the form of antibodies and killer cells, to fight off SARS-CoV-2, the virus that causes Covid-19.

But the snag is that these two mRNA vaccines need to be kept at extremely low temperatures, or they risk becoming damaged. 

And to complicate things even further, mRNA vaccine technology is new – not a single vaccine using mRNA messengers has been licensed for human use up to date.

“I don’t know if we could really even contemplate an mRNA vaccine with our present setup,”  explains Barry Schoub, chair of South Africa’s ministerial advisory committee on coronavirus vaccines. “Things may change, but with our present setup, the places where we could actually utilise it would be so limited that it would be a major challenge.”

South Africa’s challenge of keeping vaccines cool    

Maintaining a cold chain – where a product must be consistently stored at a low temperature – is important to ensure that vaccines don’t degrade or lose their efficacy. A 2018 paper in the journal Vaccine, showed that although this deterioration did not pose a safety risk to 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 adequate infrastructure to properly store doses when a Covid vaccine becomes available, according to Hussey, who also serves on the Covid vaccines ministerial advisory committee.

Schoub, who is also a virologist and former director of the National Institute for Communicable Diseases, agrees: “You can’t really store vaccines reliably and sustainably at minus 20 degrees Celsius anywhere outside the bigger cities. Especially if you’re looking at places with a hotter climate, like the Northern Cape or KwaZulu-Natal, even maintaining a freezer at minus 20 is going to be a question mark.”

This means that even with Moderna’s stability at lower temperatures, South Africa’s cold chain system may be unable to handle maintaining the vaccine at its required minus 20 degrees Celsius during transport. Fluctuations in the temperature along the way could cause the jab to become less effective and offer less protection to the person being vaccinated. 

According to Schoub, Pfizer/BioNTech are considering freeze-dried vaccines – in the form of frozen powders to which liquid is later added – which could potentially ease cold chain requirements for the 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 obstacles that will arise with maintaining a vaccine at well below 0 degrees Celsius, just regulating the temperature for our existing vaccines is already a challenge.

An assessment of vaccine management in 18 countries done by the World Health Organisation Regional Office for Africa in 2001 found that “only 47% of the indicators were satisfactorily met for buildings, cold chain equipment, and transport at the national level”.

In the Western Cape, a 2015 study published in Vaccine found that government-managed vaccine supply chains were often unable to manage the temperatures at which vaccines need to be stored, adequately. 

The average temperature of health centre fridges in the study ranged from 0.9 to 9.2 degrees Celsius, meaning that the jabs could have potentially been stored at temperatures both too low or too high and been damaged.

Why does 90% efficacy matter? 

Despite the delivery challenges of the Pfizer/BioNTech vaccine, its 90% potential efficacy has physicians and scientists, who mostly expected a much lower efficiency, excited.

Although it is only 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 shot.  

Schoub explains: “If it does turn out to be true then that is a major, giant step forward, but at this stage it’s very difficult to assess how accurate that figure is because it’s still early in the trial.”

A higher efficacy rate means that the jab is able to 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 the people receiving a vaccine are going to be protected, you need to vaccinate a much larger portion of the population in order for it to make a difference and properly contain an outbreak.

With herd immunity as the end goal – where enough of the population is protected or resistant to the virus that it stops spreading – the measles vaccine, which is 97% effective at preventing measles, is often held up as the ideal.

But until now, scientists have been skeptical that we would be able to reach the same level when it came 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 shot because of the differences between the two diseases. While both are spread in a similar manner, through coughs or sneezes, they fundamentally differ in how they affect a person’s body.

Measles is a systemic disease, meaning it affects the whole body, while Covid is initally a pulmonary disease that mainly targets the lungs. In that respect, Covid is more similar to influenza, which is what has been used as the sort of benchmark when it comes to vaccine efficacy, says Schoub.

The distinction in how the disease works matters, because it influences the type of immune response – with measles requiring the production of antibodies in the blood to fight off the measles virus and influenza needing a more complicated immune response through antibodies in respiratory secretions.

The type of immune response needed to fight off influenza is hard to get through vaccinations, with most flu jabs only offering around a 60% chance of protection from the infection.

Most Covid vaccine trials are therefore designed to pick up around 60% efficacy in a vaccine candidate, the director of the American government’s National Institute of Allergy and Infectious Diseases, Anthony Fauci, explained in a Medical Brief webinar in October.  

But regardless of whether the Pfizer/BioNTech candidate is suitable for South Africa, the issue of delivering a vaccine is something we need to begin working on now, says Hussey.

He concludes: “There is a huge cost involved in delivering a vaccine, the World Health Organisation has estimated that cost of delivery of vaccines could be up to two or three-fold greater than the cost of the vaccines alone.

“There is also the additional operational costs of conducting immunization campaigns during the Covid-19 pandemic. We have to ensure that the facilities, the staff administering vaccines and the recipients of vaccines are kept ‘Covid safe’. That’s something we need to factor into our planning.”

And even though South Africa is only expecting to get enough Covid vaccines for around 5% of its population by next year, and a large rollout to the general public will likely only come in the next two years, Hussey cautions: “I think getting the vaccine is a simple thing.

“Getting the vaccine out to the people who need it is the challenge and we don’t have a great track record in even getting routine vaccines to the communities that need them most.”

*This story was produced by the Bhekisisa Centre for Health Journalism. Sign up for the newsletter.

*This story has been updated with latest information related to the Moderna vaccine candidate,

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Aisha Abdool Karim

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