Professor Karim explains why it's difficult to stop the spread of COVID-19

Professor Salim Abdool Karim explained that without natural immunity or a vaccine, most of the population may be at risk of contracting COVID-19, which would lead to increasing the number of patients who may need hospital care.

Vital to flatten the curve as soon as possible

Several factors are in play, including the rapid infection rate of the novel coronavirus, super spreading and repeated infections waves. The infection rate only slowed down once lockdown measures were implemented.

Flattening the curve as early as possible is vital as we've seen from the United Kingdom's caseload that it's difficult to curb the spread of the disease in advanced epidemics.

In addition, curbing the spread of the disease also leads to slower community transmission and provides time for health care facilities to prepare, increase capacity and equip facilities and personnel.

Why not just eradicate the virus?

"Why talk about flattening the curve, why not talk about eradicating or eliminating the virus? Why don't we aim for a situation to just get rid of the virus?"

Professor Karim explained that it's extremely difficult to eliminate a virus altogether. Here's why:

Pre-symptomatic infectiousness

Karim explains that even before a person becomes ill with COVID-19, they are already infectious – for several days – before they begin to display symptoms themselves.

They could be spreading the virus to the people they interact with, in a range of different situations, without being aware of it.

Asymptomatic infectiousness

In addition, some people may be carriers of the virus without falling ill themselves. In fact, they may never even beware that they've contracted COVID-19, but could still infect others.

A recent study in China showed that transmissibility of the asymptomatic cases among close contacts is comparable to that of symptomatic cases.

Rapid spread

COVID-19 also spreads much more rapidly than other infections, such as the common flu.

"Before we can even catch up or try to find the cases, the virus has already spread. We know that each infected person can infect up to two others".


In addition to the above, COVID-19 is also associated "with superspreading events". Professor Karim explains that a patient in South Korea infected a large portion of her community.

A 61-year-old woman from Daegu tested positive for COVID-19 in February. It seemed like a standard case; however, it was revealed through contact tracing that Patient 31 attended two worship services.

She exposed more than 1 000 people. The rate of infection in the area doubled within 24 hours. By the end of the week, it had increased 30-fold. Kim Chang-yup, a professor for health policy at Seoul Nation said at the time:

"What made this case so much worse was that this person spent a considerable amount of time in a very crowded area. There's growing fear and resentment among the people right now."

Repeated waves

Lastly, we are in the first wave of the virus. Even when the initial spread is controlled, the risk of repeated waves and outbreaks of new epidemic waves remain. Singapore is one such example.

"It is very difficult for us to simply eliminate the virus. We have chosen the alternative, which is to flatten the curve".Professor Karim