Having caused at least four million recorded deaths worldwide, and probably almost 200,000 excess deaths in South Africa (the official figure of 65,000 almost certainly understates the true picture, which is more accurately indicated by what is called “excess mortality’’), the Covid pandemic is one of the worst in history.

After 18 months of worldwide infection and deaths and with 10-15% of survivors experiencing the unpleasant “long Covid’’ symptoms, as well as severe social, economic, and educational disruption, it is clear that the novel coronavirus, SARS-CoV-2, which causes Covid-19, is not going to go away. But, as terrible as the pandemic has been, the good news is that a number of very effective vaccines have been developed.

As we can see from the devastating third wave South Africa has been reeling under, we are likely going to keep being hit by further waves of this virus that will cause further unnecessary suffering and death until at least all adults have immunity. Our only hope for getting the Covid pandemic and its severe health, social and economic consequences under control is for as many people as possible to be vaccinated against it as quickly as possible.

Our bodies have many processes that detect and fight infection and disease: together these are called the immune system. When our bodies become infected, some cells figure out how to fight the infection, and if they are successful, and we survive, our bodies develop the memory of how to produce these cells that know how to fight this specific infection, usually far more efficiently and speedily the second and subsequent time round. This is called immunity.

Vaccinations are a way of triggering the body to develop an immune response to a particular disease without having to actually get the disease — a kind of fake first infection.

Traditionally, vaccines contain a component of the virus or other microorganism, or the organism in a weakened or killed state. The body then is able to recognise the virus when we are infected and respond to it, as if it was exposed the first time. The most recent mRNA technology, which is used in some of the latest vaccines, uses genetic material that tells our bodies to produce a protein of the virus which then stimulates the immune response.

Vaccines are one of the most successful, and safest, interventions medicine has ever come up with. They have eradicated dangerous infectious diseases such as smallpox, have controlled polio, and have saved billions of lives from measles, tetanus, pneumonia, hepatitis and diarrhoea. They have dramatically decreased viruses responsible for some cancers. They are also safe — bad side effects are very rare and the risk of developing severe illnesses is much smaller than the bad effects of the diseases the vaccines prevent.

Vaccines were not invented by Big Pharma and they are not unique to Western medicine — the first recorded use of something similar to vaccination was in China in the 16th century.

No. Immunity takes time to build up in the body.

For most Covid vaccines it takes at least two weeks after the vaccine has been administered for you to start developing immunity. Most vaccines will start providing some protection against severe illness two weeks after the first dose. However, good protection generally requires at least two doses of the vaccine, and will start materialising 7-14 days after the second dose.

All vaccines work very well against severe Covid, irrespective of the variants (different versions of the virus) that are circulating. They differ in how well they protect against infection and mild Covid (usually sniffles, tiredness and other flu-like symptoms).

At the moment, two vaccines are being used in SA — both excellent choices.

The J&J is being used as a single shot; the Pfizer as a two-dose schedule, several weeks (minimum three weeks) apart. Other excellent options, mostly two-shot, are being evaluated. Don’t stress about which one is best — the best one is the first one you can get.

Even though you have had a vaccination, you should continue to act as if you do not have immunity until three weeks after your first (J&J) or second shot (Pfizer).

Do not assume you have enhanced immunity straight after getting your jab. Continue to take precautions. Mask when indoors with people and always open windows in rooms and vehicles. 

We have seen many people get sick in those two weeks while waiting for their immunity to kick in, either infected just before or after their shot.

All the vaccines currently in use give excellent protection against severe illness and death — they keep you out of hospital and off a ventilator.

We have less good information on how likely you might be to get a mild infection of Covid, and it is possible that you could get infected. We have seen many people get mild “breakthrough’’ infections even after the full two weeks after vaccination. Often this will be so mild that you don’t know you have it; some people get worse infections which can feel like a bad cold, but they usually recover after 2-3 days.

The possibility of being mildly infected means that when you are with people who are not fully vaccinated, you should continue to take precautions of masking, opening windows and avoiding being together indoors or in a vehicle, because you could infect those who are not protected. Even though it is possible to get Covid mildly once fully vaccinated, we now know that fully vaccinated people are less likely to spread the virus. Also, vaccines will differ in how well they protect against infection and mild Covid, which also depends on which variants are circulating.

We are still learning how best to deal with these mild infections, especially with the new, hyper-transmissible Delta variant. It is possible we may need additional shots for better protection, whether of the same vaccine or a different one. Stay posted.

You may feel no effects at all. But side effects can include having a sore arm where you were injected, getting a headache, or having a fever, for a day or two. The side effects experienced are much milder than getting severe Covid (some of the authors have had this experience). Also, these side effects generally indicate that the vaccines are inducing an immune response and doing what they are meant to do.

Severe allergic reactions are very rare, but can occur after any vaccination; if they occur, the healthcare provider who administered the vaccine can immediately and usually effectively treat the reaction.

The Pfizer vaccine can cause an allergic reaction which is easy to treat, and very rarely can cause inflammation of the heart, which normally goes away quickly.

The J&J vaccine has a very rare effect of blood clotting, and can be serious; Covid causes this effect far more often, though, so the benefits far outweigh the risks. Recently, the J&J vaccine has been associated with a very rare syndrome causing weakness, called the Guillain Barre Syndrome. This syndrome is also seen in patients who have had the flu and other viruses, and is treatable.

No. But some people may not respond — not everyone’s immune system learns equally well from vaccines.

People who have conditions involving immune suppression — for example, someone who has had an organ transplant and is taking immunosuppressant drugs to stop their body from rejecting the new organ, or people on chemotherapy or taking immunosuppressives for other condition like rheumatoid arthritis  — may not develop as good immune responses from vaccines. We are learning, though, how to amend the doses so these people can get better protection — so watch this space.

In addition, people with severe allergies may want to avoid the Pfizer vaccine, or ensure that the person giving the vaccination is ready in case of a reaction.

Like all viruses, SARS-CoV-2, the virus which causes Covid, changes and develops. When a version develops that has important differences (for example, that increases its transmissibility, virulence or relative ability to evade immune responses), it is given a new label, such as the Delta version of Covid, which has been hitting South Africa hard.

The Delta variant is two-fold more infectious than the original SARS-CoV-2 virus, which is why it has been spreading so quickly. So far the vaccines are still working well in protecting against severe Covid due to variants, but vary in how well they protect against infection and mild Covid from different variants.

Scientists are working on vaccines that might work better against infection and mild Covid irrespective of mutations of the virus. It may be that we need to get a booster vaccine every few years to deal with new variants, particularly if one is at high risk of getting severe Covid. But equally, it is possible that the current vaccines may be enough.

There are 19 different vaccines currently used around the world against Covid, and more are being tested.

The vaccines mostly being used in South Africa at the moment are made by Pfizer and Johnson & Johnson (J&J). These vaccines work in very different ways. While more traditional vaccines use a component of the virus or a weakened or killed version of the virus which stimulates your body to develop an immune response, the Pfizer vaccine uses a copy of a molecule in our bodies called RNA which causes cells in our bodies to produce the protein that our immune system responds to.

The RNA vaccines do not in any way affect or alter your genes or your DNA. All the vaccines eventually get your body to respond in a similar way to how it would if infected — to produce cells and antibodies that can fight Covid-19. The advantage of the RNA vaccines is that RNA is easier to design and can be produced very quickly. Also, since it does not require the production of any form of the potentially very dangerous virus, it is also safer to produce.

It is not very easy to compare how well the different vaccines work because the trials in which they were tested used different groups of people at different places, involved different variants of the virus and used different study methods. But both J&J and Pfizer are working very well and giving people good protection against severe Covid-19, including the variants of concern identified to date.

Covid is a new kind of coronavirus, but coronaviruses are not new — the common cold we get every winter is often caused by one of the coronaviruses. This is part of what enabled vaccines to be developed so quickly. Also, huge amounts of funds and resources were mobilised very rapidly, which enabled swift development of the vaccines.

The vaccines have been thoroughly tested in multiple trials.

More than three billion doses of vaccine have been administered worldwide and in the US 150 million people are fully vaccinated. In the UK, about 55% of the population — about 36 million people — have been vaccinated. This is an extremely safe intervention.

We do not yet know. It is possible that we will need to get a booster vaccine every year or two to keep up our immunity. Modelling studies suggest that people might require booster doses every 2-3 years to protect against severe Covid. To protect against infection and mild Covid might require annual boosting. We will find out over the next two to three years. The focus of vaccination is likely to be centred around protecting against severe Covid and death, rather than preventing infection and mild disease.

Some commentators still maintain the aim of vaccination is to develop population-wide immunity, or “herd immunity”. This is when enough people have immunity that the microorganism stops being able to circulate at all. Herd immunity was an aspirational goal until the virus started showing the ability of mutating, causing it to become more transmissible and relatively resistant to antibodies induced by past infection and by vaccines.

Consequently, it is unlikely that herd immunity will be achieved with this virus any time soon, and it will probably circulate, mutate, and recirculate throughout our lifetime, reinfecting us several times, like all the other coronaviruses. Luckily, individual protection against severe illness is still possible with the current vaccines even with the mutations that have occurred. Those who do not get vaccinated will face an increased probability of infection and potential severe illness as variants of the virus continue to circulate. This risk will increase as society returns to normal.

But it is likely that everyone, unless they hide behind a wall for the rest of their lives, will eventually get the virus. It’s all about how badly you get it — whether you get it vaccinated or unvaccinated.

Having had Covid definitely does provide short-term protection from severe illness, as the vaccines do, but there is no evidence that it is better than the protection acquired from vaccines (and the consequences, as we have noted, are severe).

It is early days yet, and we will have more data to guide things, but we are aware of many cases, including among our colleagues, where people have had a second case of Covid, occasionally severe.

If you have had Covid, the good news is you have lots of protection from severe illness in the short term. However, adding a vaccine on top of this may well stimulate a slightly different response (and augment an already primed immune system), and mean you enjoy additional protection. As we point out, the vaccines are very safe, and Covid does dreadful things, occasionally even in people with prior infection, so it is worth getting the vaccine as an additional precaution. One should wait for 2-3 months after having Covid before getting a vaccine, and you probably only require a single shot.

The Electronic Vaccination Data System (EVDS) offers online registration for vaccinations and identifies vaccination sites. Once registered on the system you will be allocated an appointment at a nearby vaccination site. You could also select which site you prefer. The registration system is becoming more flexible to enable more accessibility to getting vaccinated

No. No one has to pay. If you do not have medical aid you will have free access to public sector vaccination sites. If you have medical aid it will cover the cost at the public sector or the private sites; you will not need to pay upfront. The government is in the process of setting up arrangements to ensure that all public and private sector sites can be accessed regardless of medical scheme membership.

While many public sector sites are presently not working on weekends,  many private sector sites are available. The government is working to achieve uniform coverage throughout the week. It is therefore important to get regular updates on weekend availability.

Some vaccine sites have been allowing those who are registered in the system to come for a walk-in without an appointment. Which sites are doing this, and the extent to which the appointment system is being used, seems to be changing all the time. You might wait in a longer queue if you do a walk-in.

Continue to wear your mask when indoors and to keep windows open. Covid is an indoor respiratory virus: it is spread in the air, and it collects indoors where windows are closed. You are unlikely to get it outside, and opening windows in rooms, cars, taxis and buses makes everyone much safer. As you are fully immunised only two weeks after receiving your second vaccine dose, take this into account when making decisions about interacting with people. DM/MC

Lucy Allais is professor of philosophy jointly appointed at Wits and Johns Hopkins University; Shabir Madhi is dean and professor of vaccinology at the Faculty of Health Sciences at University of the Witwatersrand, and director of the SAMRC Vaccines and Infectious Diseases Analytics Research Unit; Imraan Valodia is dean of the Faculty of Commerce, Law and Management, and director of the Southern Centre for Inequality Studies, University of the Witwatersrand; Alex van den Heever is an adjunct professor and holds the chair of Social Security Systems Administration and Management Studies at the Wits School of Governance; Martin Veller is the former dean of the Faculty of Health Sciences at the University of the Witwatersrand; Francois Venter is a professor of medicine at Ezintsha, Faculty of Health Sciences, University of the Witwatersrand.