Business Closures, Stay-at-Home Restrictions, and COVID-19 Testing Outcomes in New York City
ORIGINAL RESEARCH — Volume 17 — September 17, 2020
The positivity rate reached a maximum of 71% on March 28 and declined steadily in the next 2 months. By May 31, only 4% of tests had a positive outcome. The business activity and stay-at-home indices were near their prepandemic value of 100 until about the middle of March. At that time, the business activity index rapidly declined; on April 16 it reached a low of 22.9 and stayed below 50 through May 31. In contrast, the stay-at-home index increased rapidly, reaching a peak of 206.6 on April 8; between mid-April and May 31, it hovered around 175.
Citywide trends in the positivity rate for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and business activity and stay-at-home indices, New York City, March 3–May 31, 2020. The positivity rate gives the percentage of daily tests that had a positive result; the business activity index gives the number of visitors to points of interest (such places as stores, restaurants, parks, hospitals, or museums) in a zip code; and the stay-at-home index counts the number of smartphone devices that did not leave their home location. Both indices are averaged across zip codes (weighted by population), are lagged 3 to 7 days before the day of the test, and are normalized to equal 100 in the prepandemic period of February 4 through 6.
The opinions expressed by authors contributing to this journal do not necessarily reflect the opinions of the U.S. Department of Health and Human Services, the Public Health Service, the Centers for Disease Control and Prevention, or the authors’ affiliated institutions.