Covid-19 and vaccines: Questions and answers

Updated 15 April 2021

| GroundUp and Spotlight Staff

South Africa is vaccinating against Covid-19. Here are questions and answers about the vaccine.

Things are moving fast. Information quickly becomes outdated, or even wrong as new scientific findings are made. After each answer we put the date on which it was last updated so that you can look for newer information since it was answered. We intend to keep this Q&A updated until it’s clear the Covid-19 pandemic is under control.

No doubt we’ll make errors. Please alert us if we do and we’ll update the article. Also let us know if you have questions you’d like answered. Email us at

Updated on 15 April 2021.

Questions about safety and efficacy

How do we know vaccines are safe?

Before vaccines or medicines are rolled out they are tested for safety and efficacy. For example the Oxford/AstraZeneca vaccine was first tested on monkeys before it was given to humans. Several clinical trials have since been conducted on many thousands of volunteers.

In an early human trial of the Oxford vaccine, over 1,000 people either got this vaccine or another vaccine of no use against Covid. The researchers found no serious side effects.

In January the results of a massive trial with results from nearly 12,000 people were published (over 7,500 in the UK and over 4,000 in Brazil). People who received a placebo instead of the vaccine had more “adverse events” than those who took the vaccine.

No medicine or vaccine is 100% safe. Some have known side effects, such as pain at the injection site and a headache and some may have extremely rare adverse events that are more serious. The real question is: do the benefits outweigh the risks? So far for four vaccines a large amount of data shows that the answer is yes. Two further vaccines also appear to be safe, but full data for those have not yet been published.

(9 February 2021)

Which vaccines have been found to be safe and effective?

At the time of writing six vaccines have been successfully demonstrated to be safe and effective.

Four vaccines, produced by BioNTech/Pfizer, Moderna, Johnson & Johnson and Oxford University/AstraZeneca, have been approved by reputable regulatory authorities. The results of the fifth successful vaccine, made by Novavax, were announced on 28 January 2021. The results of the sixth vaccine made by the Gamaleya Institute were published in The Lancet on 2 February 2021.

A vaccine by Sinovac has shown promising early results in a trial in Brazil.

The Johnson & Johnson vaccine has been shown to be effective against the strain of the virus circulating in South Africa known as 501Y.V2. There is some evidence that the Novavax vaccine is effective too against this strain, but the company needs to provide more information. There is some laboratory evidence that the Moderna vaccine is effective against the 501Y.V2 strain, but more tests are needed to make a definite conclusion.

(9 February 2021)

Who decides which vaccines work?

A number of Covid-19 vaccines have been approved by the world’s leading medicines regulators, including the United Kingdom’s Medicines & Healthcare Products Regulatory Agency, the European Medicines Agency, and/or the United States Food and Drug Administration. These regulators consist of top scientists who carefully and independently study the available evidence.

Our medicines regulator, the South African Health Products Regulatory Authority (SAHPRA), must authorise Covid-19 vaccines before they can be used in South Africa. SAHPRA has a reputation for acting slowly, but also, quite deservedly, it has a good reputation for ensuring that only safe and effective medicines and vaccines are registered for use in South Africa. So far it has registered one Covid-19 vaccine (Johnson & Johnson) and conditionally allowed the use of two others (BioNTech/Pfizer and Oxford/AstraZeneca).

(14 April 2021)

What are the different clinical trials that are conducted on vaccines?

There are typically three phases of human trials before a medicine or vaccine is approved by a reputable regulatory authority such as the FDA in the United States, the European Medicines Agency or SAHPRA.

The first phase evaluates the side effects and correct dosage of the vaccine on a very small group of people. The second phase recruits even more people with the emphasis being on effectiveness.

A phase III trial is usually much larger. For vaccines this involves many thousands of participants. Typically half will randomly be selected to have the test vaccine and the remainder will receive a placebo (an inert substance) or a vaccine unrelated to Covid-19. Ideally neither the participants nor their health carers know who has received the real vaccine or the placebo. The trial is often also conducted in several different populations, and may recruit participants in different cities and countries.

Once a vaccine is being rolled out, adverse event surveillance typically continues. This type of surveillance is particularly useful for identifying adverse events that are so rare that they are not picked up in clinical trials, even very large ones.

(14 April 2021)

How do we know the Johnson & Johnson vaccine is safe and effective?

The United States Food and Drug Administration (FDA) has published a review of the Johnson & Johnson’s clinical trials, involving nearly 40,000 volunteers, of whom roughly half received the vaccine and half a placebo. Taking all of the data into account the vaccine is about 66% effective against moderate to severe/critical laboratory confirmed Covid-19.

Efficacy against severe or critical Covid-19 was substantially higher at about 85%, 28 days after vaccination. There were seven deaths in the placebo group and none in people receiving the vaccine.

The Johnson & Johnson vaccine was found to be 82% effective 28 days after vaccination against severe/critical Covid-19 caused by the 501Y.V2 variant common in South Africa.

According to the FDA: “The most commonly reported side effects were pain at the injection site, headache, fatigue, muscle aches and nausea. Most of these side effects occurred within 1-2 days following vaccination and were mild to moderate in severity and lasted 1-2 days.”

On 13 April 2021 the FDA together with the US Centres for Disease Control announced a temporary pause in the use of the Johnson & Johnson vaccine in that country after six out of 6.8 million people who have received the vaccine developed a rare type of blood clot. On the same day South Africa’s Health Minister Dr Zweli Mkhize announced that the use of the vaccine would also be temporarily halted in South Africa. Since the life-saving benefits of the vaccine clearly outweigh the risk of these extremely rare events, it is likely the pause will be lifted within days.

(15 April 2021)

How do we know the Oxford/AstraZeneca vaccine is safe and effective?

A study has been published with the results of 11,637 people who were randomly assigned to either receive the Oxford vaccine (known as ChAdOx1 nCoV-19) or a vaccine unrelated to Covid.

Of 5,807 people who received the Oxford vaccine, 30 became infected with Covid-19. Of those who did not receive the vaccine 101 tested positive for Covid-19. The Oxford vaccine group was 70% less likely to test positive. Ten people were hospitalised — all in the group that did not receive the Oxford vaccine.

There were 84 adverse events in the Covid-19 vaccine group and 91 in the non-Covid vaccine group, showing that the Covid-19 vaccine is quite safe.

Unfortunately though, in a trial in South Africa, this vaccine was not effective at reducing the number of mild and moderate Covid-19 cases against the local strain of the virus known as 501Y.V2. It is unknown if it is effective at reducing hospitalisations and deaths caused by this strain.

(9 February 2021)

How do we know the Novavax vaccine is safe and effective?

Detailed results of the Novavax vaccine (known as NVX-CoV2373) have not yet been published but are imminent. A press release says that 4,400 people were enrolled in the trial, which took place in the UK and South Africa.

The press release indicates that the vaccine had just under 50% efficacy in South Africa, where most people with Covid-19 have a new strain of the SARS-CoV-2 virus. We shall have to wait for further information to learn whether it is effective against the strain of the virus known as 501Y.V2 that is circulating here.

More details are needed and we will update this section when a scientific paper is published.

(9 February 2021)

How do we know the BioNTech/Pfizer vaccine is safe and effective?

A study has been published with the results of over 43,000 people who were randomly assigned to either receive two doses of the BioNTech/Pfizer Covid-19 vaccine (called BNT162b2) or a placebo vaccine. Each dose was given about 21 days apart.

The results of the two groups were compared to see which had more Covid cases seven days after receiving the second dose.

Of 21,720 people who received the Covid vaccine, 8 tested positive for Covid-19. Of the 21,728 people who did not receive the vaccine 162 tested positive for Covid-19. People in the Covid vaccine group were 95% less likely to test positive.

Ten people became very ill with Covid. Nine of these were in the group that did not receive the vaccine.

People who received the Covid vaccine reported pain at the injection site, fatigue, and headache, but otherwise there were no differences in side-effects from the Covid and placebo vaccines.

It is unknown if this vaccine is effective against the virus strain known as 501Y.V2 that is circulating in South Africa.

(9 February 2021)

How do we know the Moderna vaccine is safe and effective?

A study has been published with the results of over 30,000 people who were randomly assigned to either receive two doses of Moderna’s Covid-19 vaccine (called mRNA-1273) or a placebo vaccine. Each dose was given about 28 days apart.

The results of the two groups were compared to see which had more Covid cases 14 days after receiving the second dose.

Of 15,210 people who received the Covid vaccine, 11 tested positive for Covid-19. Of the same number of people who received the placebo vaccine 185 tested positive for Covid-19. People in the Covid vaccine group were 94% less likely to test positive.

Thirty people got severe Covid-19 and one died. They were all in the placebo group.

The researchers wrote: “Serious adverse events were rare, and the incidence was similar in the two groups.

It is unknown if the Moderna vaccine is effective against the strain of the virus circulating in South Africa known as 501Y.V2, though laboratory tests are promising.

(9 February 2021)

How do we know the Gamaleya Institute vaccine is safe and effective?

A study published in The Lancet on 2 February shows that the two-dose Russian Gam-Covid-Vac vaccine also known as Sputnik V is safe and effective.

Over 20,000 people were randomly assigned to receive either a placebo vaccine or Gam-Covid-Vac. From 21 days after the first dose of vaccine (the day of dose 2) 16 out of 14,964 people who got the vaccine were confirmed to have Covid-19 versus 62 out of 4,902 in the placebo group, which is an efficacy of 92%. There were no serious adverse events in the Gam-Covid-Vac arm related to the vaccine. There were four deaths, three in the placebo arm and one in the vaccine arm.

It is unknown if this vaccine is effective against the strain of the virus circulating in South Africa known as 501Y.V2.

(9 February 2021)

How do the vaccines work?

There are different types of vaccines.

Here is an explanation of how the BioNTech/Pfizer vaccine works.

Here is an explanation of how the Moderna vaccine works.

Here is an explanation of how the Oxford/AstraZeneca vaccine works.

Here is an explanation of how the Novavax vaccine works.

Here is an explanation of how the Johnson & Johnson vaccine works.

Here is an explanation of how the Gamaleya Institute’s vaccine works.

(2 February 2021)

I heard some people died in Norway after taking the BioNTech/Pfizer vaccine. Is this something to worry about?

The short answer is no.

More than 65 million people have already been given one of the Covid-19 vaccines (as of 25 January 2021).

Think of it this way: This is more than the population of South Africa. Everyday in South Africa more than a thousand people die, even without the Covid pandemic.

In the large group of people who have received a vaccine so far, especially given that many of them are elderly and unwell, we would expect many of them to die daily with or without Covid and with or without a vaccine.

The point is that although scientists are monitoring the vaccines for safety concerns, you cannot say that because people have died after taking it that it is due to the vaccine.

Norway has said that it has found no link between the vaccine and deaths of 23 elderly and unwell people.

(26 January 2021)

Will all these vaccines work against the variant first detected in South Africa? And the other variants?

Two of the vaccines, Johnson & Johnson and Novavax, have been shown to be effective against the variant known as 501Y.V2 that is prevalent in South Africa, albeit not as effective as they are against the original strain.

Also, Moderna has done tests that suggest that its vaccine is effective against this new strain, but less so.

The AstraZeneca/Oxford vaccine was not effective at reducing the number of mild and moderate Covid-19 cases against the the 501Y.V2 strain. It is unknown if it is effective at reducing hospitalisations and deaths caused by this strain.

In all likelihood as new variants of the virus evolve, vaccines will remain effective, but less so. But vaccines can be modified to be effective against new variants.

(9 February 2021)

What if there’s a new variant sometime in the future?

It’s relatively quick and easy for vaccines to be adapted to new virus variants or strains. The flu vaccine, for example, is modified every year to protect against the latest strain of the influenza virus.

Moderna, for example, has indicated that it has already started designing a variation on its current vaccine to be more effective against the South African strain. It’s also looking into whether a third dose (or booster shot) will increase protection.

(25 January 2021)

When I’ve been vaccinated, can I still infect other people?

The clinical trials that have been published so far were not designed to answer this. But it will be less likely (though not impossible) for you to be able to infect other people if you are vaccinated.

(26 January 2021)

I’ve had Covid. Should I get vaccinated?

Yes, a vaccine will give you more protection. But if there is a shortage of vaccine doses and a person in your family is older or has an illness like diabetes you may want to prioritise their vaccination over yours.

(25 January 2021)

I have a history of allergic reactions. Should I take the vaccine?

The world’s leading medical journal, The New England Journal of Medicine, says: “Someone with a history of allergies can definitely receive the vaccine — it doesn’t matter whether it’s an allergy to other vaccines or medications or to bee stings or food or pollen. However, people with these histories should be observed for 30 minutes after receiving the vaccine, rather than the usual 15 minutes.”

(26 January 2021)

I currently have Covid or may have Covid. Should I get vaccinated?

The vaccine takes several days to become effective after you’ve received it, so it probably won’t help you to get the vaccine while you’re infected. Current advice is that you should wait until you’ve recovered or your quarantine period is over and then get vaccinated.

(26 January 2021)

I’m under 18. Do I need to get vaccinated?

Right now, no, but eventually yes.

The BioNTech/Pfizer vaccine has completed testing on people from 16-years-old and up, while Moderna and Oxford/AstraZeneca’s trials were on people 18 and older; anyone at or above that age should get vaccinated.

BioNTech/Pfizer, Moderna, and Johnson & Johnson are currently testing their vaccines on children from 12 years old and up — once the results of these tests are released, and if they confirm the vaccines work and are safe, children in that age-cohort should get vaccinated.

In mid-December 2020, Oxford/AstraZeneca halted their tests on children from 5-years-old and up. They have not announced when testing on children will resume.

(3 February 2021)

I’m pregnant or breastfeeding. Is vaccination recommended?

The short answer is yes although there is still a lack of data about the vaccine in pregnant or breastfeeding women.

A more detailed answer is available here.

(26 January 2021)

What if I have an allergic reaction to a vaccine?

Current advice is that after you are vaccinated you should wait 15 minutes at the facility where you were vaccinated. If you have no allergic reaction, then you can leave. But you should contact the facility if you become unwell.

(26 January 2021)

How many vaccine doses do I need?

Of the six proven vaccines, five ideally need two doses several weeks apart. The Johnson & Johnson vaccine only requires one dose, but is also being tested as a two-dose vaccine.

(2 February 2021)

Questions about South Africa and the vaccines

I’ve heard the vaccines need to be stored at very low temperatures. Can we do this in South Africa?

The BioNTech/Pfizer vaccine has to be stored at -70°C, which requires a special very expensive freezer. Pfizer has also produced custom packaging that can keep the doses at this temperature as long as dry ice (solid carbon dioxide) is replenished every five days. Handling dry ice requires special training. It can last in a regular refrigerator that is kept between 2°C and 8°C for up to five days.

The Moderna vaccine must typically be kept at about -20°C, but can last in a refrigerator that is between 2°C and 8°C for up to 30 days.

The Oxford/AstraZeneca vaccine, Novavax, Johnson & Johnson and Gamaleya vaccines can be stored in a normal fridge.

While South Africa does not have a lot of ultra-cold temperature fridges, regular refrigeration is widespread. We also have many companies that can maintain cold-chains, to ensure that the vaccines are kept at the optimal temperature.

(2 February 2021)

How many people do we need to vaccinate to stop the epidemic?

It’s impossible to be precise but in South Africa we’d have to vaccinate tens of millions of people.

You may have heard that the aim of vaccination is to achieve something called herd immunity. Here is an explanation of herd immunity.

(26 January 2021)

Have any vaccines been authorised in South Africa?

Yes, the South African Health Products Regulatory Authority has given the green light for three Covid-19 vaccines. It has given full registration for the Johnson & Johnson vaccine - and granted what is known as a section 21 authorisation (a conditional approval) for the government to use the Oxford/AstraZeneca and BioNTech/Pfizer vaccines.

(14 April 2021)

What is a section 21 authorisation and why is it important?

Medicines or vaccines can only be used in South Africa if they are registered by the South African Health Products Regulatory Authority (SAHPRA). SAHPRA is the public institution charged with deciding whether medical products are safe and effective. It must act independently and only in the public interest.

SAHPRA deals with specific products. So it wouldn’t register, for example, all paracetamol. Each paracetamol manufacturer who wants to sell their product in South Africa must get it registered.

The registration process is quite lengthy, complicated and expensive. But there’s generally no time for this with Covid-19. That’s where section 21 of the Medicines Act comes in. It was written with this kind of situation in mind. In a nutshell, it gives SAHPRA the authority to skip its usual approval process and grant a usually temporary approval.

SAHPRA has therefore already issued what is known as a section 21 authorisation to the government allowing it to import the Oxford/AstraZeneca vaccine from the Serum Institute in India and distribute it in South Africa. (Read the press release by SAHPRA on the section 21 authorisation for the Oxford vaccine.)

SAHPRA has also granted section 21 authorisation for the BioNTech/Pfizer vaccine.

Section 21 gives SAHPRA very broad powers, so long as it acts in the public interest. SAHPRA can conceivably grant section 21 authorisations to the government or even private institutions to use the other vaccines that have been found to be safe and effective. The pharmaceutical companies that manufacture them don’t even have to apply.

So the section 21 mechanism is going to be very important in the months ahead.

(28 January 2021)

Why aren’t we making the vaccines in South Africa?

Actually Aspen Pharmacare, South Africa’s biggest pharmaceutical company, is playing a role in the manufacture of the Johnson & Johnson vaccine — doing so-called “fill and finish”. But vaccine or medicine production at scale is not something one simply turns on or off at a whim. As matters stand, we have very limited local capacity to make vaccines. Whether South African companies play a greater role in vaccine production will depend on many factors.

It would be nice if more Covid vaccines are manufactured here but much more important is to make safe and effective vaccines available to the population, irrespective of where they are manufactured. (Read about the current status of local vaccine production.)

(28 January 2021)

What is the price of each vaccine?

It depends on where you are in the world.

The EU will pay R34 per dose of the Oxford/AstraZeneca vaccine, R223 per dose of the BioNTech/Pfizer vaccine, R276 per dose of the Moderna vaccine and R132 for the single-dose Johnson & Johnson vaccine.

We know how much EU countries are paying for the vaccines because in mid-December, a Belgian minister accidentally tweeted the prices at which the EU was purchasing various vaccines, which were supposed to be strict secrets.

This price list also included prices for two candidate vaccines that have not yet released results regarding their effectiveness: Sanofi/GlaxoSmithKline is R140 per dose, and CureVac is R180 per dose.

In South Africa, medical schemes will pay for people who are insured. The government will provide vaccines free to uninsured people.

The South African government is paying $10 (about R145) per dose of the Johnson & Johnson vaccine. Government is also paying $10 per dose of the BioNTech/Pfizer vaccine – although this vaccine requires two doses and the price per person is thus $20.

(14 April 2021)

Can South Africa afford the vaccines?

A group of experts have estimated that the cost of a comprehensive vaccine roll-out in South Africa would be between R8.6 and R16.4 billion (depending which vaccines are used). This includes an extra R1.2 billion for nurses.

To put this in perspective the national Department of Health’s 2019-20 HIV/AIDS and sexually transmitted infections budget is R23 billion. The sum of provincial and local government health expenditure was R215.8 billion in 2019/2020. When the national health budget is included (R55.5 billion in 2020/2021), the total is about R271 billion. In other words, the total cost would be between 3 and 6% of the health budget.

Also, a large chunk of the vaccine rollout could be covered by private medical schemes for their members.

Given the lives that will be saved and that it is the quickest way to ending lockdowns, we cannot afford NOT to vaccinate.

(26 January 2021)

What is Covax? Is it important?

At the onset of the pandemic, many people realised that poorer countries would struggle to access vaccines.

One solution to this problem saw the World Health Organisation join forces with Gavi (the Vaccine Alliance), and the Coalition for Epidemic Preparedness (CEPI).

The solution proposed by Covax is that it gathers financial commitments by countries across the world, and negotiates with manufacturers of candidate vaccines to set aside doses of their vaccines (if they come to market) to these countries. Once available, these vaccines would then be distributed equitably among the states that are Covax members. At present, no member country will receive doses for more than 20% of their population, at least until all other countries have been covered to that degree.

Covax’s goal of ending the pandemic by providing equitable access to vaccines is very important. It has positioned itself as the only way in order to achieve this. However, there are concerns about the speed at which the facility is working. This is why South Africa has moved to secure vaccines directly from pharmaceutical companies.

(14 April 2021)

What are compulsory licenses? Do we need them?

All the vaccines discussed in this article are new and still under patent. This means, for example, that Pfizer/BioNTech have the exclusive right to produce and market their vaccine since they own the patent. While the Oxford University/AstraZeneca vaccine is also under patent, a number of companies have been licensed to produce this vaccine. Such licenses are called voluntary licenses since AstraZeneca voluntarily granted these licenses – for example to the Serum Institute of India. A WHO initiative called the Covid-19 Technology Access Pool (C-TAP) that coordinates and encourages voluntary licenses in order to boost vaccine production has so far struggled to get off the ground.

If patent-holders decide not to license other companies to manufacture a vaccine, most governments have the legal power to override that decision by issuing a compulsory license (compulsory because it is done without the consent of the patent holder). To our knowledge this has not yet been done for any Covid-19 vaccines, but some governments might consider it if there are specific manufacturers who are ready to produce a specific vaccine and the only thing stopping them is that they don’t have a license. Vaccine manufacturing is however not straightforward and it’s not clear how often these circumstances will arise.

(26 January 2021)

Who will get vaccines first? And why?

In South Africa, frontline healthcare workers have been identified as the population segment that is first in line for the vaccines. While this group has not yet been explicitly defined, it would include doctors, nurses, and paramedics.

According to government figures, this group is 1.25 million strong.

The second phase of South Africa’s vaccination roll-out will cover 16.6 million people: 2.5 million essential workers, 1.1 million people in “congregate settings”, 5 million people over the age of 60, and 8 million adults with comorbidities. As at 26 January there is no indication how people will be prioritised within this phase, or within the categories, or how many people fall within multiple categories (such as a 60-year-old policeman with diabetes and hypertension).

According to the government’s plans “essential workers” include police, miners, security, retail food, funeral, teachers, people working in banking, essential municipal services and home affairs, border control and port health services. “People in congregate settings” include care homes, detention centres, shelters and prisons, people working in the hospitality and tourism industry, and educational institutions.

Elsewhere in the world, the people in society most vulnerable to the virus, such as people living and working in care homes and the very elderly (those above 80), are prioritised, along with healthcare workers.

In South Africa, people over the age of 80 will only get vaccines in phase two, along with all other people of pensionable age. There are 577,273 people over 80 in 2020 according to StatsSA and they are far more likely to be admitted to hospital or die from Covid-19 than any other age group. People in local frail-care homes stand a 1 in 10 chance of dying if they acquire a Covid-19 infection.

No reasons have been provided why the most vulnerable segment of the population are not being vaccinated first in South Africa.

(9 February 2021)

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