A top vaccine expert in South Africa believes the country may have achieved herd immunity against COVID-19 following a major outbreak there over the summer.
Some 12 to 15 million people in South Africa — the fifth most-infected country in the world at the height of the pandemic — may now have some level of immunity against the bug, professor Shabir Mahdi told Sky News.
“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,” he said.
Cape Town-based researchers found around the time of the June-July outbreak that on average 40 percent of people tested had coronavirus antibodies — with the majority unaware that they’d been infected, Dr. Marvin Hsaio told Sky News.
About one-third of people tested in a similar study in Gauteng — home to South Africa’s largest city, Johannesburg — also had antibodies, according to preliminary results.
“Inexplicably, the numbers [of infections] started dropping off at the end of July, and at the time I couldn’t explain why,” said Hsiao.
“But when we analyzed the data it became 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.”
But a new study suggests any achieved immunity against the virus may not last for long. Scientists at Imperial College in London found that antibody levels in the British population fell from 6 percent around the end of June to 4.4 percent in September.
South Africa has recorded more than 717,800 confirmed cases of COVID-19 and 19,053 deaths, according to the latest data from the country’s National Institute for Communicable Diseases.