As of March 20th, Washington, New York, and California had a total of 11,011 combined confirmed cases, comprising 58% of all known confirmed cases in the U.S. (N= 19,069).

The first known case of COVID-19 in Washington state, and in the U.S., was confirmed on January 21, 2020. By February 1st, California had recorded their first confirmed case, but new confirmed cases were slow to accumulate. On March 2nd, New York confirmed their first case and that’s when the curve started to kick up for Washington, California and New York. Washington hit 500 cases on March 13th, 52 days after the first confirmed case. New York hit 500 cases on March 14th, 11 days after the first confirmed case. California hit 500 cases on March 16th, 44 days after the first confirmed case.

Not only did New York rapidly hit the 500 case mark compared to Washington and California, but cases have continued to rise sharply. The graph below shows the trends in these three U.S. states after they hit the 500 confirmed cases mark.

Trends in confirmed COVID-19 cases per 100 thousand residents after 500 confirmed

Seven days after hitting the 500 cases mark, New York state had 43 confirmed cases of COVID-19 per 100,000 residents, with a total of 8,310 cases. Eight days after hitting the 500 cases mark, Washington state had 20 confirmed cases per 100,000 residents, with a total of 1,524 cases. Five days after hitting the 500 cases mark, California state had 3 confirmed cases per 100,000 residents, with a total of 1,177 cases.

Italy is the European country that many in the U.S. are keeping a close eye on, hoping we don’t follow a similar trajectory for cases. Japan is a country on the other end of the spectrum that has done a great job preventing cases from climbing too steeply. Below is a graph comparing the current trajectories of confirmed cases in the U.S., Italy and Japan as of March 20th, per 100,000 residents, after each country hit the 500 confirmed cases mark.

Trends in confirmed COVID-19 cases in the U.S., Italy and Japan per 100 thousand residents after 500 cases

The United States is tracking very closely to the steep curve of Italy, while the curve of Japan has remained flat. The hope is that the recent state and federal measures to encourage and enforce social distancing will help flatten the curve for the U.S., so the curve looks more like Japan than Italy. Only time will tell, however experts currently predict the trend for the U.S. continuing to match that of Italy seems far more likely.

While the U.S. as a whole still seems like the trend is following Italy, the case for New York state is quite different. The graph below shows how New York State compares to Italy, once each hit the 500 confirmed cases mark.

Trends in confirmed COVID-19 cases in NY vs. Italy per 100 thousand residents after 500 cases

Five days after hitting the 500 confirmed cases mark, New York had 43 confirmed cases per 100,000 residents. Italy did not reach a similar mark until 19 days after they hit the 500 confirmed cases. New York currently has a total of 8,310 cases while Italy has a total of 47,021.

Data source: Confirmed COVID-19 cases from the data repository for the 2019 Novel Coronavirus Visual Dashboard operated by the Johns Hopkins University Center for Systems Science and Engineering (JHU CSSE). Downloaded March 20th, 2020.