New SA coronavirus stats raise concerns about lockdown extension – What you should know

Health Minister Zweli Mkhize revealed that South Africa has now recorded 2,605 COVID-19 cases, an increase of 99 cases since yesterday.

Most of these cases come from the three epicentres of the coronavirus in South Africa – Gauteng, Cape Town, and Durban.

The total number of cases in Gauteng is now 969, followed by the Western Cape with 675, and KwaZulu-Natal on 539.

The growth in the number of COVID-19 cases is closely linked to the number of tests conducted. The number of coronavirus tests conducted to date is 95,060, a daily increase of 4,545.

Mkhize has also revealed there were 14 new deaths attributed to COVID-19 in South Africa, bringing the total to 48.

The table below shows the total number of coronavirus cases per province.

Average number of new daily coronavirus cases

Professor Salim Abdool Karim, chairperson of the Health Minister’s COVID-19 advisory group, previously said an important figure to watch is the average number of new daily coronavirus cases.

This figure shows whether the lockdown has been effective in curbing the spread of the virus. It will also inform the decision on whether to extend the national lockdown or not.

Last week, the average number of new daily coronavirus cases was 67. The 95% confidence interval for this number is 45 to 89 cases per day.

Karim provided four scenarios for the average number of daily cases between 10-16 April.

1. Equal to or above 90 – continue lockdown.
2. 45 to 89 and the positivity to screening ratio (CHW) is above 1 in 1,000 – continue lockdown.
3. 45 to 89 and the positivity to screening ratio (CHW) is equal to or below 1 in 1,000 – ease lockdown.
4. Below or equal to 44 – ease lockdown.

Karim explained this set of criteria gives South Africa clear guidance on how to deal with the lockdown.

Passive and active cases

If one looks at the total average number of new daily coronavirus cases in South Africa – the same number used by Karim for his analysis – it points to a lockdown extension.

The average number of daily cases between 10-16 April is 95.9, higher than the 90-case threshold where the lockdown should continue.

This, however, does not mean the lockdown will be extended. There is more to the average number of new daily cases than meets the eye.

Karim explained that the criteria he listed is for passive cases and should exclude cases identified through active screening.

Passive cases refer to people who have contracted the virus and went for testing after showing symptoms.

This is what happened for the first few weeks in the country, and to compare “apples with apples” only passive cases should be used to match Karim’s criteria.

Thousands of “active screening” tests have also been conducted in South Africa, but the Department of Health does not provide a breakdown or case numbers based on active versus passive tests.

Karim said differentiating between “passive and active cases” is a key issue which the committee is currently grappling with.

If there is a significant number of active cases among the total new cases this week, and this may reduce the average number of new daily cases to below the 90-case threshold.

Current situation for total new cases

The chart below shows the average number of new daily cases between 10-16 April.

The red line, at 90 cases, is when the lockdown should continue. The green line, at 44 cases, is when lockdown should be eased.

For this comparison, MyBroadband used the total number of new daily cases – the same number which Karim used for his calculations over the past five weeks.

The active cases have therefore not been removed, as the breakdown of active and passive cases has not been publicly released.

While there are understandable concerns about a lockdown extension because of Karim’s criteria, it should be noted that there is no official plan from the government to do this.

Minister of Cooperative Governance and Traditional Affairs Nkosazana Dlamini-Zuma said the government is currently uncertain what will happen at the end of the month.

“We don’t know for sure that the lockdown will end on 30 April. Even if it does, we can’t open the floodgates,” she said.

Now read: New coronavirus stats in South Africa possible bad news for the lockdown