‘We have underestimated airborne transmission of Covid-19’, says Wits professor Shabir Madhi


University of the Witwatersrand Professor Shabir Madhi said airborne transmission of Covid-19 is a reality and has been underestimated.

Wits University’s Professor Shabir Madhi said airborne transmissions explain the rapid rate at which the coronavirus is being transmitted.
Image: Supplied/Wits

“There is emerging evidence that is cause for concern that we might have underestimated the role of airborne transmission of Covid-19,” Madhi told eNCA on Tuesday.

Madhi said previously the focus was around the notion that patients are infected when coming in to contact with contaminated surfaces.

But that has since changed, he said.

“Unfortunately, more recently based on a number of experiences, what we term as super-spreader events suggest there is a fair amount of airborne transmission taking place.

“There are two parts to it, but the part we are referring to now is extremely small micro droplets they are suspended in the air for a reasonable period time. People who are in that vicinity, especially when the area is poorly ventilated, might inhale those contaminated micro droplets and that could cause an infection,” Madhi said.

He said it was “safe to say” airborne transmissions were a reality, and that this explains the rapid rate at which the coronavirus is being transmitted.

Madhi warned that it is now more important than ever for everyone to wear masks.

After a recent study by the Spanish government and the country’s leading epidemiologists, it was found that just 5% of those tested across the country maintained antibodies to the virus.

In findings published by the medical journal The Lancet, the study also found that in 14% of people who tested positive for the coronavirus, antibodies in the first round of testing no longer tested positive in subsequent tests carried out weeks later.

Madhi said after a patient becomes infected, many people lose antibodies after two to three months, but that “doesn’t mean there isn’t underlying immunity”.

“People who have had a severe disease tend to have this antibody circulating for longer, up to about three months, compared to people who had a mild illness.

“We can’t be certain that natural infection is going to induce broad spread community immunity, which is required to be able to break the back of this pandemic.

“This is an area of concern. What it will require then is for us to get a vaccine sooner than later if natural infection is not doing the job it usually does in terms of inducing the immunity that protects one against developing severe disease and being re-exposed to the virus.”


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