Covid-19: SA achieves unique trajectory but is not out of the woods yet

Adhering to the rules of lockdown will be more important than ever during the coming week, especially to those who would like to see life return to some form of normalcy in the near future.

Health experts, who are using a scientific approach to determine if South Africa’s lockdown will continue and to what extent, say the rate of community transmission during this week is considered critical.

Professor Salim Abdool Karim, a clinical infectious diseases epidemiologist, and chairperson of the Ministerial Advisory Committee on Covid-19, shared some insight into the science behind the intervention measures government has implemented, and what South Africans can expect going into the future, during this evening’s (Monday) live public engagement (13 April).

South Africa has achieved a unique Covid-19 trajectory, seeing a plateau in the rate of infections much earlier than other countries.

This is in comparison to countries that have had significant success in containing the spread of the coronavirus, including South Korea, Japan and Singapore.

“Once a country reaches about 100 cases, the epidemic grows at a rapid rate, which is called the exponential curve. Usually, when countries get into an upward trajectory, it just keeps going. As the number of new cases starts increasing rapidly, medical care systems get swamped and are overwhelmed,” explained Prof Karim.

“South Africa was in an upward trajectory, entering the exponential curve but on March 26 the epidemic took a turn. We began to see a decline in the number of news cases reported and then we saw a plateau in the curve.”

Prof Karim pointed out that the following day, March 27, was the first day of South Africa’s lockdown.

Scientists who studied the ‘flattening of the curve’ have disregarded the possibility that this is a result of not enough testing being done, saying that the plateau occurred while the number of tests steadily increased. They also observed that the plateau occurred at a time when the public sector began to ramp up its testing, compared to the previous weeks when tests were being conducted predominantly in the private sector.

“Covid-19 decreased while overall testing increased, including in the public sector,” stated Prof Karim.

“Lockdown has essentially reduced community transmission in South Africa.”

He continued:  “When Covid-19 spreads into the community, it spreads like wildfire. In South Africa, we are seeing cases but it’s not spreading like wildfire, which makes our curve quite unique. Our intervention has led to a situation where people are not interacting with others, so each infected person becomes a dead-end. They are not transmitting the virus to others, because they are not interacting with others.”

However, the fact that South Africa has managed to stay ahead of the curve until now, does not mean the country is out of the woods.

“As much as we have managed to keep community transmission at a low level, I have to tell you a difficult truth,” admitted Prof Karim.

“Can South Africa escape the worst of this epidemic? This is very unlikely. Put simply, no, not unless we have some mojo to protect us.”

“Once we end this lockdown, 55 million people will be vulnerable to this completely new virus because none of us have any immunity. We have no vaccine. There is no treatment. That is when we are likely to see the exponential curve again.”

The rate of infection or the R0, pronounced ‘R naught’, will be used to determine if the lockdown should continue, according to Prof Karim.

An R0 of one means that, on average, each infected person transmits the virus to one other person. If the R0 is above 1, it is likely that the lockdown will continue. If the number of new cases per day increases by an average of 90 cases or more, the lockdown will continue. The lockdown will also continue if even one in a thousand people, who are screened during the home visits, is found to be positive for Covid-19.

Dr Karim cautioned against an abrupt end to the lockdown, advocating for the lockdown to be phased out, in a systematic way in order to give health care system time to prepare.

Government is already halfway through the 8 stages it has identified to manage the Covid-19 epidemic. Stage 1 involved setting up laboratories. Stage 2 was declaring a state of national disaster, stage 3 was to implement the lockdown, and stage 4 involves on-going surveillance and actively identifying Covid-19 positive patients through door-to-door screenings.

Stage 5 will involve identifying hotspots where infections are likely to flare-up. Stage 6 is ensuring medical facilities are in a state of readiness for a possible surge in the number of Covid-19 cases. Stage 7 involves the challenge of dealing with loss of life and bereavement. The final stage is to remain vigilant and to stay one step ahead of the virus.

Physician, Professor Glenda Gray, emphasised that containing the epidemic requires buy-in from the public at large. “The next couple of days will be critical as we try to contain the contagion,” she agreed.