Do SA’s Covid numbers add up, and have we interpreted the data correctly?

SA, and in fact the whole African continent, has been touted as a region that was spared the Covid-19 mortality horror of other regions like Western Europe.

The country was also recently listed as being the 18th worst hit when it comes to Covid-19.

But how accurate are these ratings and comparisons? 

According to Wits University virology Prof Shabir Madhi, we need to tread carefully when making such pronouncements.

“We need to be careful when we interpret the data,” he said recently on a webinar hosted by MyHealthLive, explaining that too many variables are in the mix.

Madhi said some of the findings are “intriguing” when you look at the numbers: comparing deaths relative to population size, SA was in fact worse off than hard-hit European countries like Spain and the UK.

“When using excess mortality data, our rate in SA is about 80 out of 100,000 people dying from Covid-19. That figure is in fact worse than the UK’s own first wave where it was 65 deaths per one 100,000. In Italy it was 110 per 100,000. So, relative to the size of our population, we were just as badly, if not more, affected than some European countries,” he said.

However, there are different ways to look at the data.

Even though our mortality rate was similar, in Spain, just under 10% of people were infected (it ranges from 2% to 12% depending on which part of the country you’re talking about). In SA, surveillance in the Cape metro suggested that 35% to 45% of urban adults were affected compared to about 10% in high-income countries.

So, the mortality rate per chunk of the population was similar, but we had far more people being infected.

From this, we can make a comparison by looking at the mortality rate among those infected — and then the numbers tell a different story to the mortality rate out of 100,000 of the general population.

With regard to the former, that is where you see that SA was “spared” in a sense: our infection mortality rate is at about 0.28% compared to New York, for example, where it was 1.2% or Spain where it was 0.65%.

“You can see, then, that our infection mortality rate was much lower than high income countries. But in terms of absolute numbers, we were just as badly affected. It’s in deaths among the infected that we were better off.”

And what about being 18th on the list of countries most affected?

Here comparisons are less clear-cut than mortalities, and Madhi said it is important to realise we’re not comparing apples with apples.

He said: “There has been a limited amount of testing in Africa. In SA, the testing rate has been 85 to 90 South Africans out of every 1,000. In the US, they are not testing at the capacity they should, but there the per capita testing is at 320 per 1,000. That is four times more than us, but then again, we are doing more testing per capita than anywhere else in Africa.”

Nigeria is the continent’s most populous country, with some 190 million living there, but only four people per 1,000 are being tested.

The country accounts for 18% of the population across Africa, whereas SA accounts for just under 5% of the population on the continent and is doing more than 40% of the testing.