Imagine a technology offering that knows your health history—and your family’s, and your neighbor’s. That can alert you if anyone in your building has had Covid-19, or is at higher risk of exposure to it because of their job. That can check whether you have Covid-19, or antibodies to it. That, once there is a Covid-19 vaccine, administers it, and reminds you when you are due for a booster shot. Imagine if it could also check your temperature and blood pressure, make sure you got the latest information about other outbreaks you should be careful about, and be around to answer basic health questions—all free of charge.