Google and Apple have unveiled new systems that help authorities track new crown virus contacts on their phones.

Alphabet’s Google Inc. and Apple Inc. announced Tuesday a new system that will allow public health authorities to use smartphones to help track new crown virus contacts without developing apps. Public health officials will be able to submit a small profile to Apple and Google using the new system, called Exposure Notifications.

The two technology companies used the file to build the system, and mobile phone users could choose to join the system to determine whether they had been in contact with a new crown virus patient.

Google and Apple have unveiled new systems that help authorities track new crown virus contacts on their phones.

In the case of the iPhone, Tuesday’s release of the new iOS operating system will alert users to whether their local health department is using the ENE system, which users can set up without downloading any new apps. Android phone users will also receive a prompt from the operating system, but will also need to download an auto-generated app.

Google and Apple say Maryland, Nevada, Virginia and Washington, D.C., will be the first regions in the U.S. to use the new system. The ENE system could also be used in conjunction with tools released by the two companies in May that allow public health officials to develop apps that allow iPhones and Android phones to use Bluetooth signals to detect users’ exposure to the new virus.

In recent weeks, six U.S. states and more than 20 countries have launched “exposure notification” apps based on Apple and Google technologies without major failures. These applications are becoming more compatible, allowing public health officials to conduct cross-border tracking. Meanwhile, other regions, such as Hawaii, are pushing ahead with another tracking technology.

However, whether “exposure notification” can effectively reduce the speed of transmission of the virus is still a big question. Most governments do not track the detailed data used by their applications for user privacy reasons. In Alabama, for example, more than 1,000 students were infected in an outbreak in August. But a university representative said it was too early to say whether Alabama’s just two-week-old app had played a role.