Apple and Google are making their COVID-19 exposure tech available to public health agencies, which means you'll soon have access to contact tracing apps

• Apple and Google are rolling out their exposure notification API so that public health agencies can start including the technology in their apps.
• 22 countries have been given access to the API along with three US states, the companies said.
• It's the first major phase of the technology. Apple and Google have spent weeks finessing the privacy elements of the app, as well as improving the level of control for public health agencies.

Apple and Google have started rolling out their COVID-19 contact tracing tech in a publicly available software update, meaning public health agencies can start building it into apps.

The arrival of the application programming interface (API) – which Apple and Google now officially call the exposure notifications system – means public health agencies can begin to roll out their own contact tracing apps to users.

The software will use Bluetooth to detect other smartphones in close proximity and alert the user – assuming they have a relevant health app installed – if they come into contact with someone who tested positive for COVID-19.

The companies said that 22 countries on five continents have received access to the API, along with three US states: Alabama, South Carolina, and North Dakota. More locations will get access in the coming weeks, Apple and Google said.

Spokespeople for Google and Apple said that in most cases the API will only be available to one app per country, but said exceptions could be made. However, this does not appear to be the case for the US, where individual states are creating their own apps.

Apple and Google consulted with several public health groups to finesse the API, including the CDC Foundation, the Centers for Disease Control and Prevention, and the Association of Public Health Laboratories.

Off the back of those talks, the API has been tweaked with several improvements for health agencies, including letting agencies themselves decide what constitutes "an exposure event" between people, and determine the level of risk from instances of someone coming into contact with a person who has tested positive for COVID-19.

The companies said they will continue to update and improve the API as they get feedback from public health authorities.

Earlier this month, Apple and Google gave us a preview of what the interface might look like on iPhones and Android smartphones. It also recently announced it had tightened some of the privacy controls around the tech, including encrypting the data that gets shared via Bluetooth.

But the bigger challenge will be for public health agencies to get people to download their apps. One study has suggested that 60% of the population would need to adopt these apps for the technology to be effective, but according to a Washington Post-University of Maryland poll, nearly three in five Americans said they would be unwilling or unable to use Google and Apple's contact tracing technology.

The UK is currently trialing its own NHS contract tracking app, which has been criticized by cybersecurity researchers who discovered several security risks.

However, it was recently reported that the NHS could be working on a separate app that uses Google and Apple's API.