The Invisible Killer Explained: A conversation about COVID-19 with renowned infectious disease specialist Dr. Michael Saag

Michael S. Saag (born October 2, 1955) is a physician and prominent researcher of infectious diseases at the University of Alabama at Birmingham. He holds the Jim Straley Chair in AIDS Research, is director of the Division of Infectious Disease and the William C. Gorgas Center for Geographic Medicine, and he also serves as head of its Center for AIDS Research.
In addition to his academic knowledge about viruses, Dr. Saag contracted COVID-19, from which he recently recovered. I spoke to Dr. Saag about the novel coronavirus pandemic the other week.

You’re a researcher in addition to being a practicing physician, correct?
Yes. Eighty percent of my time is spent on research.

Is COVID-19 that different from other viruses we’ve encountered in the past?
Yes, and I’ll tell you why. The interaction between humans and coronaviruses isn’t new, and humanity has encountered many of them over the centuries. Most of the varieties we’ve run into cause the common cold. Not every cold is a coronavirus, but coronaviruses can cause colds. They’re annoying and make people miserable for a short period of time, but they don’t kill them. The first coronavirus we know of that killed people was the original SARS in 2003 and then the MERS virus in 2012. However, SARS and MERS were both relatively short-lived. They certainly killed a number of people—well into the thousands, in the case of SARS—but they burned themselves out and went away.

And they never came back?
There have been sporadic episodes of both of these entities attempting to come back, especially MERS, but nothing has been like this coronavirus.

Explain what it is.
Its official name is SARS-CoV-2, a unique coronavirus that almost certainly came from the animal community, most likely a bat as a reservoir host, and drifted into other species. Some of those animals ended up on tables in a wet market in Wuhan, China. What probably happened was that the virus mutated and became infectious for humans. That mutation allowed it to bond with receptors in the human respiratory tract, specifically a receptor called ACE2. Once the virus was able to get a foothold on those receptors it was able to infect humans, and in this case, cause a disease that is certainly not invariably fatal, but 20% of those who contract it develop severe disease and need to be hospitalized. Of those, probably about 30% to 40% have a more advanced disease and end up on a ventilator. And of those, I don’t know the exact number, but a significant fraction depending on where they are will not survive. That’s the opening salvo.
The second thing that distinguishes this coronavirus is its contagiousness, which is very important for your readers to understand. This virus is one of the most contagious we’ve ever encountered. It isn’t quite as contagious as measles, but it’s much more contagious than influenza and probably a bit more than the common cold. It is very easy to catch, which is why we have to be so careful, at least in the United States, where we’re now talking about relaxing the stay-at-home orders. Meanwhile, I’ve been looking at Israel. As with so many other things, Israel is doing it right. They’re all over it in terms of identification of cases, tracing all those who have come into contact with someone who tested positive, quarantine and isolation. They’re doing a really good job of protecting the general population.

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