Why vaccines need to be tried and tested in different populations across the world

  • A Covid-19 vaccine will help in the fight against the pandemic
  • More than 100 trials are happening worldwide
  • However, it is imperative that participation in these trials not be limited to developed countries

The race to develop a Covid-19 vaccine continues, and positive news has been doing the rounds this week as the University of Witwatersrand (Wits) is set to embark on the Ox1Cov-19 vaccine trial – the first clinical trial in Africa for a Covid-19 vaccine, Health24 reports.

Speaking at the virtual webinar hosted by the university on Tuesday, Professor Helen Rees, executive director of the Wits Reproductive Health and HIV Unit (RHI) spoke about the importance of Covid-19 vaccine development needing to be a global effort, and stressed that the opportunity to participate in trials must ensure that Africa is not left behind like it was in the past.

Vaccine nationalism

Vaccine development earlier this year mainly came from the Northern Hemisphere and was concentrated in particular regions including China, the UK and the US and other developed economies, said Rees. They were able to look at their available technologies and move into vaccine development rapidly, but there is a global dialogue happening around this:

“The concerns that were then raised globally were that we cannot only have vaccine development in the Northern Hemisphere. We really need to have vaccines tried and tested throughout the world, in all populations, and there are several reasons for that,” explained Rees.

If trials are limited to the North, it will result in "vaccine nationalism", which typically occurs when a country’s government manages to secure vaccine doses for its own citizens before it’s made available to other countries.

In an article for Harvard Business Review last month, three medical academics wrote: “This ‘vaccine nationalism’ is not only morally reprehensible, it is the wrong way to reduce transmission globally.

“And global transmission matters: If countries with a large number of cases lag in obtaining the vaccine and other medicines, the disease will continue to disrupt global supply chains and, as a result, economies around the world.”

Rees mentioned three reasons for the need for vaccine development trials to occur globally.

Efficacy of vaccines on all population groups

“We want to know that vaccines are safe and effective in all populations and to do that we need this global spread,” said Rees.

For example, the South African trial has enrolled 50 volunteers who are living with HIV, and the researchers will assess the efficacy and safety of the vaccine in these individuals. Considering our country is the epicentre of the HIV pandemic, this inclusion is critical.

The same thought process applies in drugs to treat Covid-19 patients, as Dr Jantjie Taljaard, infectious diseases specialist at Tygerberg Hospital, Stellenbosch University, explained in a previous Health24 article that covered dexamethasone and the Oxford RECOVERY trial. Taljaard said that a couple of things need to be considered, such as weighing certain factors against the magnitude of benefit and making comparisons for different population groups, for example:

“Can the drug be recommended for all age groups, or do patients with obesity and diabetes benefit equally compared to patients with hypertension only? Were enough patients with HIV infection or tuberculosis included in the study to draw conclusions on the benefit versus risk for these populations?"

Volunteers and a sense of altruism

The second point is one that we don’t often think about, said Rees, but it’s really true for clinical trial participants.

“If you talk to people participating in trials they’ll often say: 'The reason I want to do it is because I want to give back.' Or 'I know somebody who had that disease and I want to protect, I don’t want to see that happening again,'" Rees said, adding:

“There is a true sense of altruism from many people who participate in trials, and because this is a global pandemic, there needs to be that opportunity for many people around the world to be able to express that solidarity and that global altruism.”

Access to vaccines

If South Africa participates in trials, Rees says there is quite a strong moral obligation for us to be able to say: “We’ve helped develop [what we hope will be] a successful vaccine, therefore, we want to ensure that the people in the country where it was developed and the region in which it was developed have access to those vaccines.

“Unfortunately what we’re seeing at the moment is what we’re calling vaccine nationalism, where vaccine production is being ring-fenced for particular countries. And obviously the richer countries are trying to say: ‘My country first, and all my citizens first,’” added Rees.

According to Rees, an important global dialogue has been happening about vaccine access which essentially suggests that if a certain country develops a vaccine, then these need to be available to all citizens of the world.

“There might and will have to be prioritisation because the amount of vaccine available to begin with will be limited and we might have to think about groups such as healthcare workers first, but what we are arguing is that it cannot be ‘my country and my country only’ first.” 

The more SA vaccine trials, the better 

Also on the panel was Professor Glenda Gray, member of the Ministerial Advisory Committee (MAC) and chairperson of the South African Medical Research Council (SAMRC), who spoke about the need for “five or six vaccines to be successful” to ensure we can meet global demand. Gray also commented on the importance of South Africa being involved in not only one, but many efficacy studies as local experience with an experimental vaccine is critical.

“If we are involved in the efficacy studies, we know exactly what and how it was managed in South Africa, and the regulatory authorities will then have experience with the vaccine and will make it easier for it to license." 

‘We must hit the drum very hard’

Rees also drew importance to the fact that even if we have successful vaccines through clinical trials, sufficient quantities will not be available by the end of 2021 for the whole world.

“We’re talking billions and billions of doses. So we are going to have to look at prioritisation, and there is an entire global effort at the moment which is looking at how and who do we prioritise, and that will depend on the vaccine that is successful because different vaccines have different characteristics.

“But that is where this global debate about access to vaccines becomes very important. We had the same issue with access to antiretrovirals and now we’re seeing a replay potentially with access to a successful [Covid-19] vaccine, so I think this is a drum we must really hit very hard in our region, because we will be the region that will be left behind otherwise.”

Rees commented that this is what happened with the pandemic flu vaccine and HIV antiretrovirals in the past, where Africa got left behind and ultimately received very little vaccine and months too late. “We cannot allow that to happen again,” she said. 

READ | 6 things you need to know about the first SA Covid-19 vaccine trial

Image: Westend61

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