Shortly after launching a new contact-tracing program in Ontario, a top Google executive said in a blog post published Friday that 20 US states and territories (roughly 45% of the country's population) are "exploring" using the tool Google built with Apple to create new contact-tracing programs, and that the new apps are set to launch in the coming weeks.

Google had previously said in May that three states, Alabama, North Dakota and South Carolina, would be launching apps using the exposure notification tool. Those states are still using the protocols, it appears.

Additionally, the company said during its update that 16 countries and regions outside the US have launched apps using the Apple-Google tool, while other countries - including France and the UK - have sought to build their own tools from scratch, though the UK infamously pivoted, abandoned its custom system, and adopted the Google-Apple protocol.

However, the UK has yet to launch this new app, and it's unclear when it will be ready, as the Telegraph recently reported.

Here's how the UK's app-based system (which is based on the Google-Apple system) is supposed to work, per the Telegraph.

Source: The Telegraph

The technology should enable users to track whether they came in contact with any infected people via bluetooth signals.

VP of Engineering David Burke penned the post, which was published Friday afternoon on the East Coast. Read it in full below: