Covid-19: Looking ahead to the next wave - experts discuss vaccines, variants and lockdowns

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  • Covid vaccination has been proven to keep people out of hospitals and prevent deaths, but uptake has been slow in SA.
  • SA is likely to experience a fourth wave of Covid cases in December, although its severity cannot be predicted.
  • Getting as many people vaccinated as possible is, however, key to getting endemic control of the virus.

With South Africa slowly moving out of its third Covid-19 wave, some experts have already warned that the country may experience a fourth surge as early as December 2021. But the severity of such a surge is a matter of conjecture, said Professor Adrian Puren, Acting Executive Director of the National Institute for Communicable Diseases (NICD).

“I think it’s going to be possibly different but we don’t really know,” he said. Puren was speaking during a Thought-Leader webinar hosted by the University of Free State (UFS) on 28 September.

The factors one needs to take into account, he said, is that while South Africa has a large proportion of individuals that have experienced natural infection, and vaccine rollouts are in place, there is still a significant number of people that have not been exposed to the virus, stressing the need for greater vaccination uptake.

Herd immunity becoming 'mythical'

Early on in the pandemic, the government set a goal of getting 67% of the population vaccinated to reach herd immunity. But various factors have complicated discussions around this, said Puren. Now, herd immunity is “becoming a bit more mythical”, he added.

The original virus that was first identified in Wuhan, China, had an R-value (the number of people to whom one infected individual will pass the virus) of about 2–3 people. Since then, the virus has evolved and has given rise to variants that have greater transmissibility, such as the Delta variant, currently dominating infections in SA. A person infected with the Delta variant may infect up to seven individuals, explained Puren. 

“We should be aiming [for vaccination coverage that’s] higher than that – in other words reaching even 90%, if not more, of individuals being vaccinated in order for us to have more endemic control of the virus,” he said.

Herd immunity wasn't the goal

Professor Shabir Madhi, Dean of the Faculty of Health Sciences and Professor of Vaccinology at the University of the Witwatersrand, recently expressed a different viewpoint, stating that it was unlikely herd immunity would be achieved, especially with the Delta variant circulating.

“With the Delta variant, we would need to get 85% of the population protected against infection … none of the vaccines currently come close to being able to provide [very high] protection against infection and mild disease, including the Pfizer vaccine,” said Madhi.

But herd immunity, he said, was never the goal of the vaccines – the goal was to protect against severe disease, hospitalisation and death, which they have proven to do quite successfully. 

Evolution of the virus

Professor Glenda Gray, President and CEO of the South African Medical Research Council (SAMRC), also believes that SA’s current vaccine coverage is not enough to gain control of transmission of the virus. 

Whether vaccination will prevent a fourth wave or contribute to a smaller fourth wave, is very hard to predict, she said.

“We don’t know how the virus is going to evolve,” she said. Gray added that there is a high number of people in SA who are immunosuppressed, and they can contribute to the chronic shedding of the virus. Where there is chronic shedding, there is an evolution of the virus.

“So we also have to take into account that South Africa may be uniquely different to other parts of the world because we have high levels of HIV and TB, and we have a lot of people who don’t know they’re HIV infected and are not on treatment,” she said.

On the bright side, South Africa does have very good genomic surveillance networks in place. Wherever there are outbreaks in the country, there is a concomitant selection of samples to do a genetic analysis to try and see how the virus is evolving, said Gray.

Are the Covid vaccines working?

There is a common misconception that fully vaccinated individuals should not get Covid. These cases are known as breakthrough infections and are actually expected. It’s a stance that’s been reiterated by many other South African experts, including Professor Linda-Gail Bekker, co-lead investigator of South Africa's Sisonke Covid vaccine study.

What one needs to bear in mind is that most of these infections would be asymptomatic (displaying no symptoms) and mild to moderate cases, with much less severe infections, hospitalisations and deaths, said Puren.

“Vaccines do work. They are effective. It will happen that vaccinated individuals will end up in the hospital wards, but not to the same extent as individuals who are unvaccinated,” he said. 

Data worldwide, including in SA, have indicated a rise in Covid-related hospital admissions among the unvaccinated. One CDC study found that unvaccinated people were about 29 times more likely to be hospitalised with Covid than those who were fully vaccinated.

Covid leading cause of deaths

The SAMRC tracks excess deaths over time and has been doing this for the past 20 years, said Gray.

“We predict that this year, Covid deaths will outstrip HIV as the leading cause of death in our country. We’re logging just over 230 000 deaths, of which half have occurred this year, so there’s definitely evidence that we have not been left unscathed and that we are in a critical pandemic. All of us have lost family, friends, colleagues and staff to Covid,” she said.

Return of stricter lockdowns?

There are a number of key measures that will determine whether South Africa will need to return to a stricter lockdown level during a fourth wave, said Dr Nicholas Pearce, Head of Department: Surgery at the Faculty of Health Sciences, UFS.

This includes the positivity rates (the number of positive Covid tests); the R-value; assessing the seven-day moving average number of cases; local outbreaks; and hospital admission data to determine whether they are overwhelmed or can accommodate more patients.

“These factors will then allude to whether you [should go] into or out of lockdown,” said Pearce.

The idea with vaccination, however, is to try and decrease each one of these factors so that outbreaks become less likely to occur, he said. This way, there will be fewer institutional outbreaks in universities and schools, for example. “About two weeks ago we had to close 20 schools within the Free State just to try and contain this area,” said Pearce.

Returning to a sense of normality

“I think it’s critical that we get vaccinated in order to go back to any sense of normality,” said Pearce, who added that the adoption of Covid protocols for over a year, such as the wearing of face masks and physically distancing, has mentally taken a toll on us as a society. 

“We’ve seen depression and suicide rates go up. From a medical point of view, what we have noticed during these waves is that the number of people presenting with stage 4 cancer has increased,” said Pearce, attributing this to patients likely being more hesitant to go to hospital during the pandemic or are unable to find healthcare resources, in both private and in state sectors. 

“So I’m a little bit concerned going forward. We must be careful that we don’t forget about non-Covid diseases. The quicker we can get out of this pandemic, and we’ll probably never get rid of Covid (but it will become endemic), we can go back to treating medical diseases. 

“To go back to any sense of normality we’re going to have to get a large number of people vaccinated. And I would, therefore, urge people to get vaccinated,” he said.

Considering the economic impact

“Why should we try to control transmission? Because we need our economy to start. We’ve seen how we’ve been affected by being on the red list of certain countries; this affects our economy, it affects our tourism, it affects our jobs,” said Gray. 

She added: “A lot of people have lost their jobs and if we want to interface with the rest of the world, we’re going to have to have the discussion around making sure our citizens are vaccinated.”

Pearce also weighed in, saying that the economic consequences of lockdown are “massive”. 

“What we’ve seen in the last wave is a shift in the demographics of the people infected by Covid. During the first and second waves, it was people above 60 years getting infected and dying, and during the third wave we’ve seen a large number of younger people getting infected,” said Pearce.

The reasons for this are multifold, but “we’re losing a lot of breadwinners, and in the medium to long-term, this is going to have huge economic repercussions”, he said. 

Increasing coverage

Increasing vaccine coverage is not a simple process, said Puren.

“We need to take into account what the nature of our society is in terms of access [to vaccines] and vaccine hesitancy, but it is possible for us to achieve endemic control. And I think that vaccines are the critical component to that,” he said.

While we’re heading towards that, Puren stressed the continued need for non-pharmaceutical interventions, including the wearing of face masks – and wearing them correctly; physical distancing; and ensuring good ventilation in indoor spaces. 

“All those factors still play an important role until we are able to manage this particular evolving threat,” he said.

*For more Covid-19 research, science, and news, click here. You can also sign up for our Daily Dose newsletter here.

READ | If SA had rolled out AstraZeneca vaccine, up to 22 000 deaths could have been prevented – Prof Madhi

READ | J&J Covid vaccine booster trial will allow us to get ahead and prepare for fourth wave – Prof Gray

READ | Covid-19: Three SA experts weigh in on breakthrough infections, immunity, and vaccine hesitancy

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