In a recent interview with The Guardian, the German government’s chief Covid-19 adviser, Christian Drosten, said the country had “half-empty ICUs” partly because it had brought the reproduction number below one.
Flattening the curve?
De Oliveira said, with the exception of the Western and Eastern Cape, the number had declined from three to one. In other words, the virus no longer spreads to three people for every one person who is infected.
But while De Oliveira and others believe the country has flattened the curve, not everyone agrees the drop in reproduction number is enough.
Writing for News24, Wits University’s Social Security Systems and Administration Management Studies chairperson, Professor Alex van den Heever, said it was not clear if South Africa had “flattened the curve”.
He estimated that R0 was around 1.2, saying this was not a cause for complacency.
Van den Heever said if the country carried on this trajectory, there could be 3 000 new infections per day by the end of May, and 26 000 new infections per day by the end of June.
“Any R above one will result in an inexorable rise in new infections, until such time as immunity levels reduce the R naturally by diminishing the availability of people to infect. For this point to be reached, however, millions of South Africans would need to have been infected and recovered.
“The active flattening, in fact, only occurs when R is maintained at one or below one through public health measures,” he said.
De Oliveira previously warned the infection rate in the country was likely to rise by up to 10% once the hard lockdown was lifted. But he said that the lockdown had kept the rate at around 5%, preventing thousands more infections.
Professor Alex Welte, research professor at the South African Department of Science and Innovation-National Research Foundation (DSI-NRF) South African Centre of Excellence for Epidemiological Modelling and Analysis (SACEMA) at Stellenbosch University, said determining the reproduction number was extremely difficult.
He added there were many variables and unknowns in the Covid-19 data still.
While R0 is an “appropriate lens” to look through in assessing the pandemic, Welte said “it’s changing from place to place and time to time in very complex ways”.
But the data suggested the country’s reproduction rate was indeed declining.
“I would interpret that, whatever R0 is, it is declining. That’s not weird, because the lockdown is a very forceful instrument,” he said.
But the more important question, according to Welte, was determining where the infection-spreading hot spots were, and dealing with those.
