Stopping exponential growth: How social distancing can limit spread of COVID-19

Aggressive social distancing measures, such as New Jersey's partial shutdown, may be unpopular but they're often the only way to slow the spread of pandemics like COVID-19, according to medical evidence reviewed by Kane In Your Corner.
After days of urging New Jersey residents to voluntarily cooperate with the state's coronavirus prevention policies, New Jersey Attorney General Gurbir Grewal stepped up his language this week.
"Consider this as your final warning," Grewal said Monday. "Your actions are against the law of New Jersey and you will be held accountable."
To understand why social distancing matters so much, we need to understand how viruses spread. Scientists call it "exponential growth", which means cases double over time. That makes the virus appear to be spreading slowly, until it isn't, when in truth cases have been doubling all along.
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In cooperation with medical experts, Kane In Your Corner built a simulation of how one person infected with COVID-19 can have a widespread impact. That person will infect an average of 2.5 people in five days, who then go on to infect others. That causes a chain reaction, and after 30 days that single case can cause more than 400 others.
But if the rate can just be cut in half, each person who gets infected will then also infect half as many, At the end of 30 days, where there once would have been more than 400 sick people, there will now be just 15.
"When you put something like this graphically, you put it into perspective, and you see how this can multiply," says Dr. Derrick DeSilva, who specializes in internal medicine. "Imagine if that now were 10 people, right? That number (of people infected) would now be 4,000. Imagine if it was 100 people. That number just becomes this enormous crazy number."
That's why experts say social distancing is most effective when it's done early, as it was in places like South Korea and Singapore.
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"If people are not socially distancing, they’re potentially putting themselves at risk, but they’re also putting their family members at risk," says Dr. Deena Adimoolam of Mount Sinai Health Center. "They’re putting their grandparents at risk, they’re putting anyone that their parents come into contact with, their grandparents come into contact with, all their friends come into contact with, they’re putting everyone at risk. That's how this virus spreads."
Experts caution that even when taken seriously, social distancing won't deliver immediate results in terms of reducing the rate of new confirmed cases. Because the U.S. is so far behind on coronavirus testing, they say there is a large backlog of cases still undiagnosed. And even if all cases were diagnosed, symptoms typically don't appear for five days, which means there would be many infected people not yet aware of their condition.