 In the face of the global pandemic, Apple and Google are doing something they almost never do. Work together. Beginning next month, Apple and Google are releasing software. The two companies will roll out a contact tracing system. We'll use Bluetooth to help notify someone if they've been in contact with someone who's infected. On April 10th, the company's announced a new project to halt the spread of the novel coronavirus. It's a system for automatically and autonomously logging all the people you've been in contact with. So if one of those people gets diagnosed with coronavirus, you'll get an alert saying you've been exposed and should quarantine. It's a really ambitious project, and we're only a couple weeks in, but it can make a huge difference in how we recover from the outbreak. The system works by blasting out short codes over Bluetooth, technically the Bluetooth Low Energy Beacon system. Your phone collects a log of all the codes you've received, representing all the people who have been close enough to infect you. Those codes are encrypted and constantly changing, so you can't use them to work back to a person's identity. Even if someone does test positive and decides to share that diagnosis, it's still pretty hard to figure out who the person is, although it's not completely impossible. More importantly, the codes you collect never leave your phone, so there's no master list of who's interacted with who. The details here are a little complex, and we'll link to a more thorough explanation in the description, but the important thing is it's not collecting absolute location data, and there are a lot of measures to keep you anonymous while you're using it. Apple and Google hope to make an API available to public health agencies by mid-May, which means that by the summer you could see an app using this system built and distributed by your state government. In the months after that, they're going to ship it as an update to iOS and Android. So it'll still require explicit permission, they're not trying to sign anyone up for this against their will, but don't be surprised if you start seeing pop-up notifications asking if you want to join the project. That's important because by the time the summer gets here, we're going to really need a system like this. We don't know how the outbreak is going to play out, but optimistic projections show US hospitalizations peaking in April and declining throughout May, assuming we keep social distancing restrictions in place and do everything else right. As we start to open up again, we're going to need some way to keep contagious people quarantined while everyone else goes back to work. And because people can be contagious for five days before they show any symptoms of the disease at all, that's going to be really hard. People who work with outbreaks have a system for doing this, although we've never done it at this scale before. It's called contact tracing. Basically, when someone gets a positive diagnosis, you sit them down and run through everything they did during a contagious period. Where they went, who they talked to, anyone who might have been close enough to catch the disease. Then you find all those people and get them into quarantine, making sure this particular infection doesn't spread any further than that circle of people. If you're doing enough tests and quarantining enough people, then the disease has nowhere to spread. We've seen this system work for coronavirus in countries like Singapore and South Korea, and it's generally been through mobile alerts. It's a lot easier to get 15 people's phone numbers than to track down 15 people in person. And if you cut out the interviewer and just have an app do it, it's even simpler. Outside of Singapore and South Korea, most countries haven't been able to launch a contact tracing app, although a lot of places have tried. But having Apple and Google on board means you know this system will ship to billions of phones, and you know there won't be any permissions problems about collecting the Bluetooth app. They're the only two companies in the world that can do this, so having both of them signed on makes a huge difference in what you can do. At the same time, there's a lot that Apple and Google are explicitly not going to do. They're not building the alert apps or setting rules for how to quarantine. They aren't even touching the question of how you verify that everyone who sends an alert through the app actually is infected, reading out the trolls and false positives. All they've built is a way to log contacts and send alerts, and then a way to get that system onto phones. Everything else is going to come down to the public health agencies, which have never dealt with anything on this scale before. There's a real question as to how much people trust them with this system, and an even bigger question as to whether they can pull it off. So far, most of those agencies have been too busy scrambling for hospital beds and ventilators to get much of a contact tracing effort underway. We still don't have nearly enough testing, and the federal response has given way to a kind of free-for-all among the states, who were already running out of resources. Apple and Google just can't solve that problem. But if the system they've laid out is going to work, those agencies and the public sector in general are going to have to get better fast. So we're doing a ton of reporting on the system, and there's a lot that didn't make it into this video. So we're leaving a bunch of links in the description, and there's a bunch more stuff coming that's going to be on the site in the next week or so. So stay tuned for that, and otherwise, stay safe out there.