6 minute read
Health Sciences
Everything you need to know about COVID-19 vaccines
By Profs Tivani Mashamba, Veronica Ueckermann and Theresa Rossouw
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Experts at the Faculty of Health Sciences at the University of Pretoria came together to answer the following common questions that people may be asking about COVID-19 vaccines.
Why should we be vaccinated, and what are the benefits of agreeing to be vaccinated against COVID-19?
The age-old cliché, prevention is better than cure, is very appropriate in the context of COVID-19 as we do not yet have a definitive cure. COVID-19 can have severe and life-threatening complications, and vaccination can save lives—not only our own, but also the lives of others.
Is the vaccine safe?
Yes, the vaccines have gone through all the usual clinical testing steps, namely Phase 1, 2 and 3 trials undertaken to establish their safety and efficacy and the optimal dose. These phases were conducted more rapidly than usual, often in parallel. Thousands of participants were involved in the studies and were closely monitored. It should also be borne in mind that scientists gained extensive experience from the effects of the first Severe Acute Respiratory Syndrome (SARS) epidemic and Middle East Respiratory Syndrome (MERS).
What is the acceptable percentage of efficacy required to consider a vaccine adequate?
According to the World Health Organisation, the minimum percentage is 50%.
Do any of the vaccines have side effects? If so, what are they?
Allergic reactions are rare, but there may be some redness and tenderness at the injection site for a few days. The most common side effects experienced by people who have been vaccinated are flu-like symptoms, such as body aches, headache or fever, which do not mean they have an infection but is a sign that their bodies are mounting an immune response—a good thing. A rare form of blood clots has been described after the Johnson & Johnson and AstraZeneca vaccines, but the risk is estimated to be 1 in a million.
Is it safe for people with co-morbidities to take the vaccine?
Yes, several co-morbidities, such as high blood pressure, heart disease, lung disease and obesity, increase the risk of dying from COVID-19. Therefore, the vaccine trials specifically enrolled people with co-morbidities to test the safety of the vaccines in those populations.
Can a COVID-19 vaccine cause infection with the virus?
No. Since the vaccine contains only a tiny portion of the virus and not the entire virus, it cannot give you COVID-19.
Who should avoid vaccination?
The vaccine is not registered for children. Therefore children, pregnant women and anyone who has previously had an allergic reaction to a Messenger Ribonucleic Acid (mRNA) vaccine should not receive such a Coronavirus Disease (COVID) vaccine, as the Pfizer vaccine.
Do you have to continue wearing a mask after receiving the vaccine?
Yes. Although vaccines significantly reduce people’s chances of getting COVID-19 and decrease the likelihood of severe illness or death, immunity is not immediate or necessarily complete.
Should I get the COVID-19 vaccine even if I have already had COVID-19?
Yes. While you should have some natural immunity after being infected with the virus, you need to be vaccinated to avoid possible future COVID-19 infection, this is not long lasting and may not protect against new variants.
Is the vaccine administered in two doses? What will happen if you skip the second dose?
If you do not receive the second dose, the efficacy of the vaccine will be significantly reduced, but this only applies to some vaccines. According to a recent publication, the Oxford vaccine, for instance, has only 76% efficacy after the first dose, but efficacy increases after the second dose.
Don’t procrastinate—vaccinate!
Note: Prof Tivani Mashamba-Thompson is the Deputy Dean of Research and Postgraduate Studies in the Faculty of Health Sciences, while Prof Veronica Ueckermann is the Acting Head of Infectious Diseases and Head of the COVID-19 Response Team and Prof Theresa Rossouw is a Clinician Scientist and Professor in the Department of Immunology.
Health Sciences
UP researchers discover new compounds with the potential to eliminate malaria By Prof Lyn-Marie Birkholtz
A team of researchers at the University of Pretoria (UP) has discovered potent new chemical compounds that show potential as candidates for both the treatment and elimination of malaria.
Prof Lyn-Marie Birkholtz, Professor in Biochemistry based in the Faculty of Natural and Agricultural Sciences and affiliated to the UP Institute for Sustainable Malaria Control (UP ISMC), and the incumbent of the South African Research Chair in Sustainable Malaria Control, was part of a team that shared this discovery. She explained: ‘The breakthrough involves identifying unique compounds that can kill several stages of the malaria-causing parasite and can block the transmission of the parasite between mosquitoes.’
The deadly malaria parasite Plasmodium falciparum occurs in South Africa and is transmitted to humans by female Anopheles mosquitoes. Since only chemical drugs effectively kill these parasites, new anti-malarial drugs are urgently needed to address the growing concern regarding anti-malarial drug resistance.
Prof Birkholtz described the parasite as a ‘shape shifter’ as it can take on multiple forms once it has entered the human body. Some of these forms cause disease, and others allow the parasite to be transmitted back to mosquitoes to continue the life cycle. She added: ‘To eliminate malaria, we must have the necessary tools to kill all the different forms of the parasite. We will then be able to cure patients of the disease and block the malaria transmission cycle, which is as important. Once this becomes possible, we will be able to eliminate malaria.’
To this end, the team searched for new chemical compounds to which the parasite has no resistance and discovered some compounds that kill the disease-causing form and others that block the parasite from infecting mosquitoes in the lab.
The two potent compounds target processes essential to the parasite’s survival: one is a clinical candidate against tuberculosis that blocks cell membrane synthesis, while the other is an anti-cancer candidate that targets epigenetic mechanisms.
said Prof Birkholtz.
The team’s discovery was made possible by using an open-source chemical compound set called the Pandemic Response Box, developed by the Swiss-based Medicines for Malaria Venture (MMV) and Drugs for Neglected Diseases Initiative (DNDi). This box contains compounds that can be used for drug repurposing/repositioning, a process by which drugs that have activity against a specific disease (eg cancer) can be reused for another condition (eg malaria).
Prof Lyn-Marie Birkholtz is a Professor in Biochemistry and the incumbent of the South African Research Chair in Sustainable Malaria Control, a transdisciplinary institute focusing on integrated innovations towards malaria elimination in South Africa. Professor Tiaan de Jager, Director of the UP ISMC and Dean of the Faculty of Health Sciences at UP, said: ‘A discovery of this kind addresses Africa-centred societal challenges and attests to the leading expertise in antimalarial drug discovery at UP and in South Africa.’
Prof Birkholtz’s team led the transmission-blocking drug discovery effort in partnership with the South African Malaria Drug Discovery Consortium (SAMDD), which included two other South African research chairs, namely the Chair in Drug Discovery at the Drug Discovery and Development Centre, H3D at the University of Cape Town, held by Prof Kelly Chibale, and the Chair in Medical Entomology at the WITS Institute for Research on Malaria at the University of the Witwatersrand, held by Prof Lizette Koekemoer, as well as scientists from the CSIR and international partners from the USA and Spain. The work has benefited from sustained funding received from the MMV and the Medical Research Council’s Strategic Health Innovation Programme (SHIP).
Prof Lyn-Marie Birkholtz in the laboratory
Chemical compounds are screened
