The Daily Gamecock

Guest Column: Let's cooperate to keep R_t below 1, beat the coronavirus

This past Friday night, I was awakened by a raucous student party next door. The noise traveled through their walls and mine. It was so loud that I had to go to the other side of my house to sleep.

I am a USC math professor and I live close to campus. Usually, I don't mind the noise. There's nothing wrong with some harmless fun. And especially after long periods of quarantine and isolation, everyone can understand the urge to socialize.

But, unfortunately, the coronavirus is still with us, and the dangers remain very real. According to the CDC and the Covid Tracking Project, the coronavirus has killed around 170,000 Americans — of late, roughly 1,000 every day. Many of us have experienced issues with our physical or mental health. The virus has shuttered businesses and sent the unemployment rate to levels not seen since the forties. To name just one example, my beloved City Yoga has closed its studio for good. As all of us are wondering, when can we get back to normal?

When analyzing the spread of the virus, an important quantity is R_t, or the "effective reproduction rate." According to the models developed on the website rt.live, South Carolina's current value of R_t is currently estimated at 0.94. Roughly speaking, that means that every South Carolinian who gets the virus infects 0.94 more.

If you're in my calculus class this fall, you'll see how coronavirus spread can be modeled in terms of exponential growth or decay. Since 0.94 is less than 1, we currently have decay: the coronavirus is on the wane, and we can expect conditions to improve. But if R_t rises above 1, then we arrive at exponential growth. Or, as UNC's student newspaper described it right before their campus was shut down, a "clusterf---."

What affects R_t? Mostly, safety precautions: mask wearing, hand washing and social distancing. The CDC recommends smaller gatherings, outdoors if possible, in which individuals from different households wear masks and remain spaced six feet apart. In other words, by all means see your friends, but don't throw the sort of party that wakes the neighbors up.

Out of caution, I opted to teach both of my classes online this fall. But President Caslen, as well as many of my colleagues, were more optimistic: that campus could be safely opened, that football could be played and that Gamecocks could be trusted to look out for each other and control the virus. Many — perhaps most — people on campus are doing exactly that. For this, you have the gratitude of the entire community. These efforts will be most effective if all of us participate.

The mathematical consequences of the model are striking: We do not have to live like monks, nor eliminate every possible source of risk. We only have to take enough precautions to keep R_t below 1. It's a bit of a pain; I, for one, would rather be out swing dancing. But ultimately it is not so bad, and it certainly beats the alternative. Let's all prove to President Caslen that he was right to put his faith in us.


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