Will there be a fourth wave in South Africa?

South Africa expects a fourth wave of Covid-19 infections to hit in early December, which will likely last for as many as 75 days, according to the former chairman of the government’s ministerial advisory committee on Covid-19, Salim Abdool Karim.

This estimate assumes that the fourth wave will follow a similar pattern to the third wave, which appears to be waning amid a sustained decline in infections across the country over the last few weeks.

President Cyril Ramaphosa appealed to South Africans to get vaccinated in an address to the nation on Sunday evening (12 September). He said that over a quarter of all adult South Africans have received at least one vaccine dose and more than 7 million people are fully vaccinated.

“The more people that get vaccinated before December, the less likely it is that we will experience a devastating fourth wave over the holiday period. When we are vaccinated, we will be able to return our economy to full operation and create the jobs that our country needs,” Ramaphosa said.

He noted that the government is considering introducing vaccine passports as part of the effort to reopen the economy fully. Further details would be announced in a fortnight.

The president warned over the potential for the municipal elections, scheduled for 1 November, to spread transmission of the virus. “In exactly 50 days’ time, South Africans will go to the polls in local government elections. It is vital that as we undertake this great democratic exercise, we do everything within our means to prevent a resurgence of Covid-19 infections,” he said.

“We know that a vaccinated person can still be infected and can still pass on the virus to others. Most importantly, people who are vaccinated against Covid-19 are far less likely to die of the disease,” he said.

Existing variants

Deputy vice-chancellor of Research and Innovation at the University of KwaZulu-Natal, professor Mosa Moshabela warned of a high risk of resurgence in new coronavirus infections if lockdown regulations are not balanced.

He told the SABC that adherence to rules around the various lockdown levels, “is not something we are good at”. He pointed to the upcoming elections specifically, as an area for concern around the spread of Covid-19.

Researchers have identified a new SARS-CoV-2 variant, which they refer to as C.1.2. It has been detected in all provinces in South Africa at a relatively low frequency.

Professor Moshabela said that the C.1.2 does not appear to be taking hold as much as the previous variants, “but we can still be surprised because slight mutations in some of these variants can actually lead to resurgence”.

He noted that the Mu variant – known by scientists as B1621, and on the WHO’s list of “variants of interest” – is still being observed and is being likened to the Beta variant in the sense that it has a strong tendency towards escaping immunity.

He said that the threat of a fourth wave is real.

A fourth wave

A team of medical experts at Wits University last month discussed the likelihood of a fourth wave in South Africa, and more importantly when it is likely to occur.

“Frustratingly, this is not clear. We are guessing any time from October/November, because it seems to be following a cyclical pattern in many places, every six months, here and elsewhere. But the surges in different places, even between South African provinces, vary widely, with the peaks differing by two to three months, as well as in severity.

“Many countries, like ours, had a worse second and far more intense third wave; others have had two waves but with high levels of infection in between, and in some, the second wave wasn’t as bad.

“Portugal had a third wave just a few weeks after the second. India’s third wave was devastating. So, wait and see and be prepared. In highly vaccinated countries, almost all the deaths are in unvaccinated people, which is why South Africa should single-mindedly focus on this.”

The medical experts outlined two likely scenarios for South Africa- based on the understanding of SARS-CoV-2 – Covid-19.

Scenario 1 – and most likely

In this scenario, the infection becomes more like a common cold or seasonal flu. After several further epidemic waves, the virus continues to circulate indefinitely in a series of smaller waves, infecting people (vaccinated and unvaccinated) repeatedly every year or two, like the other circulating human coronaviruses, the team at Wits said.

“We may see more major waves if a new more transmissible variant similar to Delta emerges, but it is likely the most transmissible versions are fighting it out.

“For people with prior infection or who have been vaccinated, every subsequent infection means on average less severe illness. For instance, a first infection can range from no symptoms at all, to a severe illness putting you in hospital or to giving you long Covid (which we explained in a previous article) after even an initial mild infection, but subsequent infections are less and less severe.”

The specialists said that in summary, it’s a race: you get the virus or you get the vaccine. “If you gamble on the virus, as some anti-vaxxers will, you put yourself and others at risk of all the Covid-19 consequences, and if lucky, will survive and be immune.

“You will also put others at risk, even if your own infection remains without symptoms or runs a mild course. If you get the vaccine, you fast-track your immunity at a far lower risk of illness.”

They said that immunity to SARS-CoV-2 may prove to be transitory, and reduce to next to nothing over a few years, much like with flu. With flu, getting the disease or getting the vaccine protects you, but immunity is lost quickly, which is why we have to vaccinate annually.

The best-case scenario is that natural infection or vaccines provide permanent protection; the “flu’’ scenario is the worst case, and again there are variations where we may have to “boost’’ in more vulnerable populations every so often.

“We think that if the above scenario is in play, and mass vaccination occurs quickly, we can be back to almost or total normal within a year, provided 80% or more of adults are vaccinated. In this scenario, vaccinated or previously infected people can probably congregate as normal, with little or no restrictions.

“Until large numbers of people are infected or get vaccinated, though, and we see that subsequent infections are shrugged off like the common cold, the masks and physical distancing will need to stay — to protect the unvaccinated.

“There are variations of this scenario, where the virus mutates to a more benign form, or even spontaneously disappears – we think this is highly implausible – or we get a super-vaccine that totally protects from repeat infections – also unlikely – but means the same thing: life gets back to a normal.”

Scenario 2: Not much changes

In this scenario, the virus continues to circulate indefinitely, evolving as it goes to escape our efforts at becoming immune, and continuing to cause lots of severe disease as it’s doing now.

“We think this is not likely because both natural and vaccine-derived immunity would have to fail to be significantly protective against severe disease for the new variants, and that’s not what we’re seeing.

“Our immune system is incredibly sophisticated, and the virus likely has a limited number of options of evading it while causing severe disease.”

Michelle Groome, Harry Moultrie and Adrian Puren, all at the National Institute for Communicable Diseases (NICD) pointed to a dramatic reduction in severe Covid-19 disease as a result of the national vaccine rollout.

“Any epidemiological analyses will need to take the vaccine coverage into account in order to make sense of the data.”

“We need to accept that surges will occur, new variants will appear and booster shots will be needed. We need to move away from considering South Africa to be in a wave or between waves or preparing for the next wave, and start accepting the reality of living with this virus in a world where we can now prevent severe disease,” the NICD said.

Read: 6 things you still can’t do under South Africa’s adjusted level 2 lockdown