The number of new COVID-19 cases being reported in South Africa is currently trending below the estimates that the Department of Health were working off of.
Minister of Health Zweli Mkhize told journalists on Tuesday they expected the total number of confirmed cases to have reached between 4,000 and 5,000 by around 2 April.
However, on 31 March the number of new positive COVID-19 cases identified in South Africa had reached 1,353.
The projections the government used to predict the number of infections on South Africa are understandable. Data from elsewhere in the world shows the number of coronavirus infections increases suddenly and exponentially.
Flattening the exponential curve of infection has required drastic intervention by governments, such as imposing strict physical distancing rules, intense contact tracing, or placing their countries under lockdown.
Mkhize said the number of active cases in South Africa may still rise rapidly as the government ramps up testing around the country.
The charts below show how the number of confirmed COVID-19 cases tracks against the Department of Health’s estimate of 5,000 cases by 2 April.
Chart: Total number of positive COVID-19 cases in South Africa
We plotted the graph of the estimate from 23 March, when President Cyril Ramaphosa first announced that South Africa would go into lockdown.
Chart: Daily number of positive COVID-19 cases in South Africa
The following chart is a representation of what the number of daily new COVID-19 cases would have looked like, assuming they increased every day and accumulated to approximately 5,000 total cases.
Decline in number of tests
When the first daily decline in the number of new active COVID-19 cases was reported locally, the National Institute for Communicable Diseases (NICD) explained it was cleaning patient data to ensure the information was verified and accurate.
“Data cleaning is required to conduct deduplication of contents and to correct details of patients in order to determine the most effective public health intervention,” the NICD said.
Another reason for the lower number of new confirmed coronavirus cases was the lower number of tests conducted.
This is set to change soon, as Ramaphosa announced this week that South Africa will roll out a screening, testing, tracing, and medical management programme on a huge scale.
“Around 10,000 field workers will be visiting homes in villages, towns, and cities to screen residents for COVID-19 symptoms,” he said.