CAPE TOWN- Epidemiologist and infectious diseases specialist, Professor Salim Abdool Karim says in order to stop the spread of Covid-19, South Africa will need to overcome five main challenges.
The Mercury, IOL and ANA proudly presents South African epidemiologist and infectious diseases specialist, Professor Salim Abdool Karim, as he discusses South Africa's response to the Covid-19 Pandemic with Viasen Soobramoney.
Posted by The Mercury on Friday, July 3, 2020
Here’s why it is difficult to stop the spread of Covid-19:
1. Pre-symptomatic infectiousness
Karim says there have been a number of cases where people spread Covid-19 without knowing they are infected and before they show symptoms of the virus. This is known as pre-symptomatic infectiousness.
“They don’t know they have it, they are not sick but they are already spreading the virus,” he said.
2. Asymptomatic infectiousness
“Then you have those that will not get sick and won’t show symptoms but they are infected with the virus. This is when people are asymptomatic,” said Karim.
Several studies have found that asymptomatic Covid-19 patients are as likely as those with symptoms to further the spread of the virus.
The US Centers for Disease Control and Prevention (CDC) recently estimated that 35% of cases are asymptomatic and that 40 percent of transmissions occur before people develop symptoms.
Karim says that asymptomatic cases are more common among the younger population.
3. Rapid spread
Covid-19 spreads primarily from person to person via small droplets from the nose or mouth that are expelled when an infected person sneezes, coughs or speaks.
The rapid spread of Covid-19 occurs when an infected person can infect more than two others.
“When this virus spreads, it spreads rapidly,” said Karim.
A superspreading event is most likely sparked by a single, highly infectious individual who often does not show signs of illness and may unwittingly share an enclosed space with many others.
Superspreading can be defined when the number of cases transmitted is disproportionately high compared to general Covid-19 transmission.
“We have seen some superspreading events, for instance, patient zero at St Augustine’s Hospital caused the spread of the virus to 14% of all the infections in KwaZulu-Natal,” said Karim.
A large number of people are not spreading the virus, he continued, because they wear their masks and practice physical distancing. All it takes is a small number of people who do not adhere to the rules for the spread to rapidly increase.
5. Repeated waves
“Even when you think the initial epidemic is under control, you can get these repeated waves that can come through. We saw this in Singapore when they had no new cases for a while but then suddenly a whole lot of new cases appeared in their migrant worker’s hospital,” said Karim.
Last month a new cluster of infections was reported in Wuhan, China, the epicentre of the coronavirus outbreak. The reported cases came after the lockdown on the city was lifted.
It was reported that all of the latest cases were previously classified as asymptomatic, people who test positive for the virus and are capable of infecting others but do not show clinical signs such as a fever.
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