Exposure Notifications

APHL, Apple, Google and Microsoft collaborate to bring exposure notifications to the public health community Through a collaboration with Apple, Google and Microsoft, APHL is helping to bring COVID-19 exposure notifications to the public health community. This effort supports the novel coronavirus response by enabling state and territorial public health agencies to provide COVID-19 exposure notifications to residents who wish to receive them.

How Exposure Notification Works

An important way to combat the spread of an infectious disease like COVID-19 is through contact tracing. Public health officials contact, test, treat and advise people who may have been exposed to an affected person to break the chain of disease transmission. Exposure notifications augment that work by using privacy-preserving digital technology to tell someone they may have been exposed to the virus as quickly as possible.

How APHL Supports Exposure Notification

By participating in Apple and Google's Exposure Notifications System (ENS), APHL helps deliver this groundbreaking technology to public health agencies. An essential element of exposure notifications is a unified digital language for communication, known as exposure notification keys. Rather than each state and territorial public health agency bearing the burden of building and hosting its own key server, a national key server, hosted by APHL on the Microsoft Azure Cloud, securely hosts the keys of those affected users. This enables exposure notifications across the US by assuring that users can find out when they may have been exposed by users from other states.

To reduce the effort needed by public health agencies to bring exposure notifications to their jurisdiction, APHL has also made available a multi-tenant verification server running on Google Cloud. As a part of ENS, a verification server is necessary to ensure a user has received a positive test result before uploading their temporary exposure keys to the national key server. Rather than each public health agency standing up its own verification server and deciding on a verification approach, providing one verification server reduces the time and complexity to deploy ENS.

Learn more about how exposure notification technology works and its privacy protections.

Participating States

States with an exposure notification app on the National Key Server:

Alabama
Alaska
Arizona
California
Colorado
District of Columbia
Hawaii
Louisiana
Maryland
Massachusetts
Minnesota
Missouri
Nevada
New Jersey
New Mexico
New York
Utah
Virginia
Washington
Wisconsin

Map of states with an exposure notification app

States piloting an exposure notification app with a limited population on the National Key Server:

Oregon

States that have discontinued an exposure notification app:

Connecticut
Delaware
Michigan
North Carolina
North Dakota
Pennsylvania
Wyoming

Learn More About COVID-19 Exposure Notifications