After months of research and a year of waiting, the reality of a Covid-19 vaccine has finally dawned. SA has secured 20 million doses that it expects to be delivered in the first half of the year, and is preparing to start rolling out the first Covid-19 vaccines this month.
As the possibility of getting a jab is becoming a reality for some, this raises a few questions around how the vaccine will work and what to expect. In search of clarity, we spoke to a team of researchers at 1DaySooner, an international nonprofit organisation that advocates on behalf of Covid-19 trial volunteers.
Q: Will the vaccines that have been prepared and are being rolled out be effective against the new strains of Covid-19?
A: Right now, all the strains we know of seem to still be responsive to the vaccines. In general, it is rare for viruses to be able to mutate enough to escape vaccines, but it is possible the virus will mutate in such a way as to eventually evade the vaccine. This is not yet a problem with any known circulating strain of Sars-CoV-2, and researchers are already preparing for that eventuality. If a strain does emerge that renders vaccines less efficacious as to be a problem for herd immunity, it becomes a relatively quick process to develop a new mRNA vaccine and roll that out to the public. Further, if it is determined that protective immunity lasts only a year or two with the existing Covid-19 vaccines, a booster programme can readily be established as we have with DPT (diptheria, pertussis, tetanus toxoid) requiring occasional booster doses.
Q: Will all the vaccines we’ll be getting be two-dose vaccines? If so, why do we need two doses?
A: All approved vaccines (Moderna, Pfizer/BioNTech, Oxford/AstraZeneca, SinoVac, Sinopharm) are two-dose vaccines. Johnson & Johnson is developing a one-dose vaccine, but it has not yet finished clinical trials. The reason most vaccines are given as two doses is because this leads to a stronger immune response. After the first dose, the body starts to produce some immune cells that recognise Sars-CoV-2. The second dose triggers these cells to proliferate and reinforces the immune response. Therefore, two doses provide improved protection compared to one dose. Given the current limitations of vaccine supply, there have been proposals to vaccinate people using only one dose instead of two. This would have the advantage of vaccinating twice as many people. However, further investigations would be needed to discuss with any confidence the efficacy of providing only one dose of vaccines approved for use with a two dose regimen.
Q: How will we know the vaccine is working?
A: Vaccines are tested in clinical trials to see if they are safe and effective. We know that the vaccines work because in those trials, vaccinated people were less likely to develop Covid-19 than people who were given placebo vaccines. For example, in the Moderna vaccine trial, 11 out of 15,210 people who were given the vaccine developed Covid-19, but 185 people in the equal sized placebo group did. Now that clinical trials are complete and more people are being vaccinated, we should start to see a decrease in Covid-19 cases in vaccinated populations.
Q: Will I have to wear a mask and social distance once I’ve had the vaccine?
A: Because the vaccine does not begin working immediately, people who were vaccinated should certainly wear masks at least until the vaccine is effective. The timeline until this occurs is unclear but seems likely to be at least two weeks. It is also not completely clear if the vaccine fully prevents infections or only eliminates symptoms, making it possible for people who were vaccinated to infect others. Above and beyond that, countries should generally not end mask mandates until the vast majority of people are vaccinated and the virus is nearly or completely eliminated.
Q: What are some of the most common side effects of the COVID-19 vaccine?
A: The Centres for Disease Control and Prevention provides a list of expected, common side effects from receiving the Covid-19 vaccines. These side effects are a result of your body’s immune response and are expected with just about all vaccines (whether flu, shingles, Covid-19 or others). These include pain or swelling at the site of the injection, and you may experience fever, chill, fatigue or headache for the next day or two after receiving a vaccine.
Q: Is there anyone who should not get the vaccine?
A: The CDC recommends that anyone who has had allergic reactions to any of the components in the vaccines, and specifically anyone with an allergy to poly ethylene glycol or polysorbate, should not get the mRNA vaccines but opt for one of the others. Those with a history of severe allergic reactions not related to vaccines are urged to get vaccinated for Covid-19.
The team of researchers from 1DaySooner who contributed equally to this article consists of David Manheim, Merrick Pierson Smela and Ginny Schmit.
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