SA has delayed the viral onslaught, but we cannot avoid it – Karim

Prof Karim is pro-vice chancellor at UKZN, director of Caprisa, and holds various international professorships, including adjunct professor of immunology and infectious diseases at Harvard and professor in global health at Columbia.

The chair of the technical advisory group to government on Covid-19, Prof Salim Abdool Karim, says the interventions introduced by the SA government have slowed the viral spread and the country has gained some time. But that is all. The virus will still hit us.

“As much as we have succeeded in stemming the flow of this virus in our communities and keeping the transmission at reasonably low levels and having the success that no one else has achieved, we cannot escape this epidemic – unless South Africa has some protective factor, let’s call it a mojo, (unless) we have a mojo that protects us, that is not present anywhere else in the world.

“Our population is at high risk because all of us have no immunity to this virus.”

Nonetheless, the delay is important because there simply are not enough hospital beds to accommodate the thousands of people who will need to be hospitalised if the numbers increase rapidly.

“We simply cannot provide care to so many people at one time,” he says.

Apart from China, every country has had the virus introduced through travellers and it has spready very rapidly.

The time lag from the day one is infected with Covid-19 and showing symptoms is between 4-7 days. By comparison, the serious symptoms of HIV-Aids only exhibit about 7 years after acquiring the infection.

If each infected person can infect only one other person, the transmission is static. The success or failure of combating an infection is indicated by how many more infections happen above or below the one-person marker.

Currently in South Africa, “we’re not seeing a situation where one infected person leads to many infections”.

But that can change very quickly and the numbers can multiply rapidly. Let’s say we have 10,000 infected people and each person on average infects up to three others, within a few days the number of infections can reach 90,000 people.

Typically, when countries have reached an exponential (rapid) rate of new daily infections, it creates pressure on healthcare facilities as people who develop illness seek medical care.

In March, South Africa was also trending towards a very quick infection rate – with the highest number of new cases per day peaking at about 200 cases in mid-March and an average of more than 100.

The country managed to avoid the exponential rate of new daily infections because of the declaration of the state of natural disaster and the national lockdown on March 26. As a result, the number of new cases per day has reached a plateau (the curve has flattened).

Currently, the daily average is 67 cases.

This is due largely to the curbing of local community transmission as a result of social distancing measures, hand washing and closing of the borders.

The flattening of the curve happened despite increasing testing (although our testing numbers remain low).

“Lack of testing may be a contributor but is certainly not a dominant one,” he says.

The country has also thus far avoided much incidence of clinical disease, “large national increases in the amounts of respiratory distress”.

However, this is temporary.

We cannot completely avoid a peak of infections.

“If community transmission increases, then cases will increase and the exponential curve will start again.

“What we would hope for is that the number of new cases will steadily decline and will disappear.

“I’m sorry to tell you that’s very unlikely. The more likely scenario is that once we end the lockdown and we’re going to have to end it at some stage, as soon as the opportunity arises for this virus again, we will see the exponential curve again.”

Delaying the peak impact on hospitals also buys time to find faster testing abilities and securing a vaccine.

SA’s response includes active case-finding, using thousands of community healthcare workers, screening people and referring them for testing.

Daily transmission monitoring will determine responses.

Given an average daily infection of 67 cases, the range in cases is from a low per day of 45 to a high of 89.

  • If daily cases increase by more than 90 infections, the lockdown will continue.
  • The lockdown will also stay in place if daily cases increase at the average of 67 cases, AND active community screenings show a rate of infection above one in a thousand people screened.
  • If average infection is 67 AND active community screening results in less than one person in a thousand being found to be infected, the lockdown can be eased.
  • It will also be eased if absolute cases drop below 45 infections a day.

“If we end the lockdown abruptly, we run the risk of undoing all the effort and the benefit we have achieved. We need to plan for a systematic easing of the lockdown.”

Prof Karim says future interventions government must address include the following:

  • Identifying hotspots, there the virus has broken out. “We need to find out where the clusters of infection are occurring, we need to slow it down. We need to be very careful that every hotspot that emerges, we can deal with it.”
  • Medical care to be ready when patients start arriving, including having triage facilities in field hospitals outside the established facilities to avoid them becoming overwhelmed – “we hold the pressure off the main hospitals who are treating the seriously ill patients”.
  • Dealing with the challenges of bereavement – the mental health and social consequences of death and dying.
SA has delayed the viral onslaught, but we cannot avoid it – Karim
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