The factors that affect our health and safety in this pandemic are social distancing, testing for the virus’ presence, contact tracing, and the availability of a vaccine. Reducing the rate of infections allows the medical system to cope with the people who get sick and hopefully keep more of them alive, and you are less likely to get sick if you stay home. It’s a good idea for people to know whether they’re sick with Covid-19, and that’s why we need reliable tests, and many millions more of them than are presently available. If you get sick, it’s a very good idea to check the people whom you might have exposed to the virus, so that they can be quarantined and not make others sick. Contact tracing has been done before for what are euphemistically called “social diseases,” and it worked to prevent their spread.