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Joburgers could have reached herd immunity without even knowing it - experts

Picture: Thobile Mathonsi/African News Agency (ANA)

Picture: Thobile Mathonsi/African News Agency (ANA)

Published Sep 12, 2020


The Covid 19 virus could be running out of people to infect in Gauteng, this because so many of its residents might have already had the virus.

In some areas of Gauteng studies have shown that between 35% and 45% of residents were exposed to Covid 19, and most didn’t even know they were infected with the potentially deadly virus.

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This, believes Professor Shabir Madhi, the executive director of the vaccines and infectious diseases analytics research unit, could be the reason why the country is seeing a sudden decline in Covid 19 infections.

“So, once you get a high proportion of the population infected and together with the use of the non pharmaceutical intervention like the wearing of masks, and physical distancing etc, what happens is herd immunity kicks in,” explains Madhi. “This where a large enough percentage of the population has now developed immunity against the virus. So the virus is no longer able to transmit efficiently between people.”

The fall in the infection rate over the last couple of weeks, has prompted speculation that President Cyril Ramaphosa could within a couple of days move the lock down to Level One. On Wednesday night, Ramaphosa told members of the SA National Editors' Forum (Sanef) in a virtual conversation to "watch this space" when asked about easing the lock down.

South Africa’s decline in Covid infections goes against what other countries, in particular in Europe, are currently facing.

Many are fighting a second wave of the disease, and are enforcing harder lock downs.

"The mystery is that despite so many people getting infected and with such a high percentage of the population possibly becoming infected, why didn’t this translate into severe disease or excessive numbers of deaths,"says Madhi, about South Africa’s experience of the pandemic.

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He explained that researchers had conducted tests in the Western Cape and Gauteng, where they looked for Covid 19 antibodies. The results so far show that both provinces possibly experienced higher than anticipated infection rates.

Professor Alex van den Heever, who holds the Chair of Social Security Systems Administration and Management Studies at Wits University explained this high immunity to the disease didn’t have to be wide spread to limit the national infection rate.

"So, in high risk areas, where people have had difficulty social distancing and have had to use taxi transport, those communities appear to have had a high prevalence," says Van den Heever. "So maybe these very localised but very important areas have allowed immunity to build up."

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Those working in communities fighting the disease have also with a sigh of relief seen this slow down in Covid 19 infections. Dr Hemant Makan during the peak was sending three to four tests a day to the laboratories for testing. Any patient that was symptomatic would be tested.

“We haven’t had a positive swab in three weeks,” the family physician whose practise is based in Lenasia, says. Makan is part of the SIM task team, a community initiative in Lenasia that was mobilised to fight the Coronavirus.

"If there is one thing we have learnt in the last six months is that we don't know a lot. It has been very difficult to understand what is going on. And the phrase we often used was let's see what happens next week," recalls Dr Yazeed Seedat, who is also a part of the SIM initiative.

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At the peak, the SIM team often struggled to find hospitals to take their patients because of a shortage of beds.

In the coming weeks Madhi and other researchers will be doing more testing to understand how the disease spread and to explain why so many South Africans became infected with the virus, but didn’t become seriously ill. They have yet to work out just how much of the population of Gauteng was exposed to the virus.

“Studies we have done are localised to certain communities. It might very well be that the percentage of the population with Covid 19 in highly densely populated areas like Soweto, Alexandra and the inner city, is greater than those people living in the likes of Sandton and Houghton. This is because of different circumstances,” he says.

But still Van den Heever warns that following the protocols of social distancing, mask wearing and hand washing are still important and a change in behaviour could bring a spike in infections.

“If we started acting like we did in February, we will probably see a resurgence. But if we maintain the current protocols, we might see the continuation of the downward trend.”

The Saturday Star

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