Most of the Covid-19 numbers we have paint only part of the picture and can easily be misinterpreted. Here are some tips on understanding the numbers.
Confirmed versus actual cases
Every day, Minister of Health Dr Zweli Mkhize provides the total confirmed cases and the increase in confirmed cases since the previous day. But how much can we really tell from these numbers?
Confirmed cases are only a fraction of the total cases in the country. Maybe the real number of cases is twice or maybe it is 10 times the reported cases; we simply don't know. As testing scales up, the picture may become a bit clearer. Unfortunately, in the past 10 days or so the number of tests has declined from a peak of 8,066 on 27 March to 1,225 on 6 April. (Hopefully this will improve in the next few days if the government successfully rolls out the 45-minute GeneXpert testing machines.)
The number of confirmed cases depends on the number of tests done and how well those tests are targeted. All other things being equal, a sudden increase in testing capacity might result in a sudden increase in confirmed cases. This would not mean that there...