COVID-19: The race to vaccinate South Africa

Written by Mayuri Ramnarain MBChB IV and Kaylee Stella Harris MBChB III

Figure 1 ⁽¹⁾

2020 was a monumental year, earning its place in history due to one of the most devastating and unprecedented events the global community has ever experienced: the COVID-19 pandemic. On a global scale, COVID-19 has caused national lockdowns, overwhelmed healthcare systems, increased unemployment and plunged the world into an economic recession. To date, a total of over 2.5 million people have died due to COVID-19 and its complications.⁽²⁾

2021 brings its own challenges, with a scientific focus being on the emergence of numerous variants of COVID-19. The race to vaccinate the world hinges on the scientific community’s ability to modify vaccines as the virus mutates and adapts itself.⁽³⁾

Vaccine effectiveness against new COVID-19 variants

In December 2020, a sudden rise in COVID-19 cases was attributed to the emergence of the new variants 501Y.V1 (B.1.1.7) in the United Kingdom and 501Y.V2 (B.1.351) in South Africa (RSA).⁽³⁾ After July 2020, new infections in RSA suddenly declined, leading scientists to believe that we had achieved herd immunity. Professor Shabir Mahdi, Dean of the Faculty of Health Sciences at Wits, told Sky News that he believed 12-15 million South Africans had COVID-19  immunity. Meanwhile, virologists in Cape Town began analysing blood samples provided by pregnant women and HIV patients for COVID-19 antibodies. Researchers found that 40% of samples contained COVID-19 antibodies, with the majority of patients unaware that they had been infected in the first place. A similar study in Gauteng revealed that 33% of those tested had been infected.⁽⁴⁾ In RSA, high rates of transmission in a population with high levels of immunity towards the original COVID-19 strain may have generated the conditions necessary for mutations to occur and variants to rapidly spread.⁽³⁾

Figure 2: Mutations arising in SARS-CoV-2 spike on sustained human-to-human transmission and human-to-animal passage⁽⁵⁾

The UK and RSA variants have a mutation in the receptor-binding domain of the spike protein which increases transmission by between 40% and 70%. The 501Y.V2 variant has two more mutations in the spike protein that enable the virus to escape the immune system. A fundamental issue is whether existing COVID-19 vaccines will be effective enough against these new variants. Moreover, these variants might be the first of many to come, leading to further severe epidemic peaks as seen in December 2020.⁽³⁾

This pandemic can only come to an end when vaccines that are effective against new variants are delivered equitably and timeously worldwide. When high-income countries treat vaccine procurement as a race to purchase the maximum amount of stock, they leave low and middle-income countries unprotected. This is at the risk of further variants emerging, some of which existing vaccines will not be effective against. These variants have a worldwide impact. Booster shots or reformulating vaccines may be needed to control variants.⁽³⁾

The Johnson & Johnson Vaccine

As of the 1^st of March 2021, RSA has vaccinated over 65 000 healthcare workers with the Johnson & Johnson (Janssen) vaccine. RSA is the first country to administer this vaccine.⁽⁶⁾ The Johnson & Johnson vaccine is a viral vector vaccine that uses a modified adenovirus 26. The DNA of this adenovirus is modified to produce the SARS-CoV-2 spike protein. The body responds to this by producing antibodies against these proteins which are then ready to combat a Covid-19 infection. In addition, the viral vector does not have the ability to reproduce and therefore does not pose a threat to the immune system.⁽⁷⁾

Figure 3: The Johnson & Johnson Viral Vector Vaccine for Covid-19⁽⁷⁾

The Johnson & Johnson vaccine confers 57% protection against moderate to severe disease from the 501Y.V2 strain at 14 days post vaccination.⁽⁸⁾ Significantly, the vaccine has prevented 100% of virus-related hospitalisations and deaths.⁽⁸⁾  Currently it is only available to be rolled out in a stage 3 clinical trial capacity in RSA. On the 28^th of February the U.S. Food and Drug Administration granted the vaccine emergency use authorisation. This vaccine is ideal for being distributed in a RSA setting because it is single dose and is stable at 2-8°C, a temperature at which we have the capacity to store it.⁽⁸⁾

Why not use the AstraZeneca vaccine?

On the 8^th of February, after acquiring 1.5 million doses, the AstraZeneca vaccine was found to be inefficient against mild and moderate COVID-19 in an RSA setting. Moreover, the most recent phase of the study was carried out on 2 000 people, with an average age of 31. Data was therefore unable to prove effectiveness in an older population with co-morbidities: the precise population for which COVID-19 is proving so deadly.

It is therefore imperative that the Department of Health remains resilient and flexible with their vaccine rollout plans. It is also essential for every individual to note that vaccines are not the holy grail. No vaccine is 100% effective, and may not prevent you from infecting others. Non-pharmaceutical methods of protection will remain the mainstay of practice for the future: social distancing, hand washing and wearing of masks.

Use the following University of Pretoria library link to read the full article:

https://UnivofPretoria.on.worldcat.org/oclc/8916367614

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