As South Africa confronts a second wave of Covid-19 infections, scientists say new evidence indicates that at least a quarter of the country’s population – and possibly more than a third – may already have been infected by the virus during its first wave, which peaked in July.
South Africa’s unusually high infection rate – potentially far higher than in some European nations after their first waves – appears to have been accompanied by an uncommonly low death rate, with early data from one province suggesting that the Covid-19 mortality rate was less than half that experienced in the worst-hit countries.
Scientists warn that their preliminary figures could go up or down as more data becomes available in the coming weeks.
A total of 19,000 people will be involved in a string of nationwide surveys. Experts also note the risks involved in trying to extrapolate from one country to the rest of a continent.
But, if confirmed, these findings could have huge significance in South Africa and beyond, and might help to shed light on the reasons behind the relatively low death rate seen in many African countries, as well as helping governments to understand which communities are most at risk from the virus and how best to modify economically damaging lockdowns.
On a recent, rainy morning in Soweto, a group of health workers moved from one community to the next, taking blood tests to check for antibodies that indicate past infection by Covid-19. This type of survey is considered a far more accurate system for measuring a country’s overall infection rate than trying to extrapolate from laboratory and hospital data.
“These surveys are very important. There’s still so much that is just unknown,” said Dr Portia Mutevedzi, a senior epidemiologist at Chris Hani Baragwanath Academic Hospital in Soweto.