A COVID-19 patient’s iPhone receives its daily contract tracing message from the city of New York on November 19, 2020, in Brooklyn, New York. (Photo by Andrew Lichtenstein/Corbis via Getty Images) Agencies may want to establish a national strategy for contact-tracing apps The absence of a national exposure notification app led 26 states, territories and Washington, D.C. to seek out their own. Sep 10, 2021 By Dave Nyczepir