South Africa may have developed some sort of herd immunity to COVID-19, according to scientists in the country. This theory came about after health authorities reported a surprising drop in cases after the initial peak.
South Africa had the fifth-highest COVID-19 cases in the world at the height of the pandemic, but it appears to have avoided the second wave of infections which is currently sending countries in Europe, and elsewhere, into lockdown again, according to The Independent.
Several studies conducted in the Western Cape and Gauteng indicate that in some areas nearly 40% of respondents had developed coronavirus antibodies and that majority of them were unaware that they had been infected.
On the basis of these findings, Shabir Mahdi, a professor of vaccinology at the University of Witwatersrand, told Sky News that he believed coronavirus had developed a level of immunity in approximately 12 to 15 million South Africans.
“What has happened in SA today, the only way to explain it, the only plausible way to explain it is that some sort of herd immunity has been reached when combined with the use of non-pharmaceutical interventions… like the wearing of masks, physical distancing, ensuring ventilation when indoors and so on,” said Mahdi.
“Herd immunity” is widely used and has become a part of the pandemic lexicon, but what exactly does it mean?
The terms ‘carries a variety of meanings’, according to the journal of Clinical Infectious Diseases. However, a common implication of the term, they say, “is that the risk of infection among susceptible individuals in a population is reduced by the presence and proximity of immune individuals”.
At local clinics, researchers in Cape Town began testing the blood samples provided by pregnant women and HIV patients for traces of the virus.
The results revealed that 37% of pregnant women and 42% of people infected with HIV tested positive for COVID-19 antibodies.
“The presence of antibodies in people’s blood sample shows that they had been infected by Sars-CoV-2, the virus that causes COVID-19, and while this indicates some degree of immunity it does not necessarily mean they will be protected from the virus if reinfected,” says health journalist, Adele Baleta in Spotlight.
“Although clinical studies are ongoing, there is no certainty of how much protection antibodies offer or for how long.”
The preliminary findings from a similar study in Gauteng reveals that approximately one-third of people tested had been infected.
Dr Marvin Hsiao told Sky News that he was surprised when the number of COVID-19 infections started to decline at the end of July, and at the time, he couldn’t explain why.
“But when we analysed the data it become clear, this immunity within the population level (linked to) the big surge infections is probably the main reason why we’ve seen the decrease of numbers of infected,” he said.
Researchers believe that the strict lockdown which came into effect in March failed to suppress COVID-19 as it forced people into close proximity with each other in the country’s densely packed townships.
Residents also had to queue for essential provisions like food and social security payments during lockdown, this created what Dr Hsia called “new networks for the spread of the disease”, which helped to accidentally fuel a huge wave of infections, as social distancing was practically impossible to enforce.
“There might be a question in terms of the duration of immunity… based on our experience with other coronaviruses, a mild infection is probably going to (generate immunity) for two to three years but that places us in a really good position,” said Dr Mahdi.
Dr Mahdi added that “…COVID is the most important cause of death this year, superseding HIV, TB and everything else but the response needs to be much more nuanced than simply believing that a highly restrictive lockdown is going to get rid of the virus.”
“Under no circumstances is a lockdown on its own going to achieve the elimination of the virus.”
Picture: GroundUp/Ashraf Hendricks