Limiting the Spread of Coronavirus

As of today, there are 1,322 cases of coronavirus in the U.S, and 12,462 in Italy. Italy has taken extreme measures to limit the spread of this disease – basically locking down the country for the next month. Schools and large gathering places are closed, travel is banned, and the only places open are grocery stores and pharmacies. Looking at data from worldometers.info, it may be working. Since March 1st, the growth rate for Italy is still accelerating but at an rate of 23% per day, compared to 34% for the U.S. Even though Italy has 10 times the cases as the U.S., that is because the U.S. had 75 reported cases on March 1st while Italy had 1,700, roughly where the U.S. is today.

These extreme measures may be tough to implement in the U.S., but if the lock down is the reason for the 23% growth rate, it may be worth it. If the U.S. could reduce the growth rate from 34% per day to the growth rate in Italy, the number of cases a month from now would be reduced by more than 90%. This reduction in the growth rate would mean 10,000,000 fewer cases over the course of the next month. See the graph below.

This kind of simple extrapolation is not meant to be an accurate forecast of the number of cases one month from now. There are other factors that could impact the spread of the disease. Spring weather may help, for one. What this example is intended to illustrate is the importance of acting now to limit the spread of the disease in the near future, because it is possible that 1,322 cases today could grow to a million in less than one month.