DM168 Analysis

A snapshot of global Covid-19 vaccines

By Christi Nortier 9 January 2021

Graphic: Jocelyn Adamson and Christi Nortier

To date, more than 15.9 million doses of Covid-19 vaccines have been administered in 37 countries. Almost half of all countries rely solely on the Covax facility for access to vaccines, and they may have to wait until 2022 for their shipment. We take a look at which vaccines have been dispensed, and where.

First published in the Daily Maverick 168 weekly newspaper.

The world’s need for numerous Covid-19 vaccines

Out of the hundreds of Covid-19 vaccine candidates, seven have already been given approval for general use or authorised for emergency use. And all of the world’s countries want their fair share of them. Already, more than 8.25 billion doses have been bought up and some 15 million doses have been injected across 37 countries. These seven vaccines have the same effect, but work differently in the body and require their own means of transport, storage and administration. And at each stage the entire enterprise could collapse.

What is it that vaccines do in the body?

Vaccines may vary in their makeup, manufacturing and storage, but they all prepare the body to annihilate Covid-19 before it even encounters it. Vaccines assist the body’s own natural defence against disease: the immune system’s strength and its ability to remember past confrontations with a disease.

When the immune system first encounters a pathogen (a virus, bacteria or other micro-organism that causes disease) it produces antibodies. The antibody’s task is to eliminate a specific antigen – the part of the pathogen that causes sickness. However, the production of antibodies takes time.

A vaccine familiarises the immune system with how to produce these antibodies ahead of encountering the virus. A vaccine consists of a minute, weakened and non-dangerous version of the pathogen that causes disease. The vaccine provokes an immune response without the antigen being present. This way, the immune system can understand how to produce the specific antibodies ahead of encountering the antigen and can react more swiftly.

In addition, it produces “memory cells” that can recollect this antibody recipe. When the immune system encounters the antigen again, its reaction time will be much quicker.

What are the different types of vaccines being used against Covid-19?

The vaccines that have been either approved or authorised for early use against Covid-19 use one of four different technologies:

Nucleic acid/genetic vaccines

These vaccines use synthetic virus genes to trigger an immune response.

The vaccine does not alter the genes of the vaccine recipient in any way. The genetic material causes the body’s cells to produce the antigen. This in turn stimulates the production of antibodies. The immune protection lasts a long time, but the genetic instructions combust within a few days. The vaccines made by Pfizer-BioNTech and Moderna use this technology.

Viral vector-based vaccines

These vaccines also provide the body’s cells with genetic instructions; however, the vehicle is different. Instead of genetic material, this vaccine uses a harmless virus to transport the instructions. The body’s cells produce the antigen, which triggers antibody production. The vaccine for Ebola makes use of this technology. The Covid-19 vaccine made by AstraZeneca and Oxford University, as well as the Gamaleya Research Institute’s Sputnik V vaccine, use this technology.

Inactivated vaccines

These vaccines contain viruses whose genetic material has been destroyed. However, they can still provoke an immune response. This technology is used in the vaccines for measles, mumps and influenza, among others. The only approved Covid-19 vaccine using this technology is one by Sinopharm and the Beijing Institute of Biological Products.

Protein-based vaccines

These vaccines contain either fragments of or entire virus proteins. Some might be attached to tiny particles. This triggers an immune response. The hepatitis B vaccine uses this technology. A protein-based vaccine for Covid-19 is yet to be approved, but potential vaccines produced by Novavax, Sanofi and Bektop use this technology.

We have some vaccines – now what?

The search for Covid-19 vaccines has been “phenomenally successful”, considering that usually only about 10% of vaccine candidates are eventually licensed, according to Professor Shabir Madhi.

He is a professor of vaccinology at the University of the Witwatersrand and the director of the South African Medical Research Council: Vaccine and Infectious Diseases Analytics Research Unit.

Recently, he has led the South African leg of the Novavax Covid-19 trial and the Oxford/AstraZeneca vaccine Covid-19 vaccine trial.

However, each vaccine faces four “valleys of death”, he explains. The first is getting licensed. The second is scaling up manufacturing to meet global demand – this is where it is at, right now.

The third is affordability and access. The fourth is the implementation of an immunisation programme.

“To some extent that becomes the biggest challenge of all in terms of the public health value of vaccines materialising,” he explains. “You can have the greatest vaccine but if you can’t eventually get people immunised then those vaccines count for very little.”

Why try to gather different vaccines?

The point of sourcing approved Covid-19 vaccines from different companies is so that more vaccines can be administered over a shorter period of time.

Madhi explains: “Unfortunately, at this point in time it is extremely unlikely that we will successfully get the number of vaccines we require from a single supplier.

“[Most] of the vaccines that will be produced over the next six months [are] pretty much spoken for because of the AMC, which SA did not engage in early enough. That’s where we are.”

In addition, a country needs to have the infrastructure to realistically deploy a vaccine – whether that’s cold storage or the ability to administer two doses of a vaccine weeks apart. DM168

 

This story first appeared in our weekly Daily Maverick 168 newspaper which is available for free to Pick n Pay Smart Shoppers at these Pick n Pay stores.

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  • If I read right, all these vaccines attempt to replicate a healthy immune response to the pathogen. This logic assumes that our compromised bodies or “assailable” bodies need the vaccine help to create a synthetically modified response so that when the virus does come along, our bodies with the help of the vaccine, then react to prevent the effects of the virus from making our bodies sick.

    Why can medical technology not try find a substance that kills the virus, rather than a vaccine which merely mitigates its effects ?
    If I understand correctly of course, the drug Acyclovir does exactly that with the zoster virus causing chicken pox, shingles, herpes and brachyradial pruritus. In other words, it’s been done with virus before.

    • Hi Wendy vaccines can induce either sterilizing or non-sterilizing immunity. Sterilizing immunity is where the virus cannot infect you in the first place – the immune system is primed so efficiently by the vaccine that it destroys any invading virus before it can set up an infection. This is not a synthetically modified response – its a natural but potent immune response induced by a vaccine. There are also programs globally to try and develop better treatments that can kill the virus once someone is infected. However, the best way to shut down this pandemic is to prevent infection in the first place using a vaccine.

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