Google revealed a Covid-19 (coronavirus) exposure tracing app API jointly developed with Apple was updated to enable cross-border use, as it highlighted deployments across more than a dozen countries.

The company noted in a blog 16 countries across Africa, Asia, Europe, and North and South America had launched apps based on the pair’s Exposure Notification technology, which was released in May in a bid to bolster virus tracking efforts.

One recent update enables interoperability between countries, with another helping authorities better assess the risk level of a user’s exposure. User controls have been simplified and an alert added to remind consumers the technology is in use.

It added 20 US states and territories accounting for approximately 45 per cent of the country’s population are also developing apps based on the technology, with debuts “over the coming weeks”.

Rather than each state hosting its own server to store tracing data, Google highlighted a recent partnership with it, Apple, Microsoft and the US Association of Public Health Laboratories to offer a single national server which will allow national sharing of data sets and notifications.