I didn’t realise that this was news to Americans, but many countries around the world have developed apps to help with Covid detection and tracing. I had one on my phone in Australia, and now I’ve got one in Germany. This one uses recently provided APIs from Apple and Google so it’s always running but doesn’t drain your battery. It uses Bluetooth and keeps a log of anonymous IDs for other devices you come in contact with over the previous two weeks. If you test positive, there’s a button you hit in the app, and it later registers as potential risk for those with your device ID. It’s incredibly useful. Isn’t it amazing what governments can do if they actually believe in science and build strategies accordingly?