2. Make millions of diagnostic tests available. Not everyone needs to be tested, but everyone with symptoms does. The nation needs to gear up to perform millions of diagnostic tests in the next 2 weeks. This was key to success in South Korea. Every decision about managing cases depends on sound medical evaluation and the results of diagnostic tests. Without diagnostic tests, we cannot trace the scope of the outbreak. Use creative ways to mobilize the nation’s research laboratories to assist with population screening; refer persons who screen positive for further evaluation. Organize dedicated clinical test sites in every community that are physically apart from other care centers, such as the drive-through test centers that have begun to spring up…

4. Differentiate the population into five groups and treat accordingly. We first need to know who is infected; second, who is presumed to be infected (i.e., persons with signs and symptoms consistent with infection who initially test negative); third, who has been exposed; fourth, who is not known to have been exposed or infected; and fifth, who has recovered from infection and is adequately immune. We should act on the basis of symptoms, examinations, tests (currently, polymerase-chain-reaction assays to detect viral RNA), and exposures to identify those who belong in each of the first four groups. Hospitalize those with severe disease or at high risk. Establish infirmaries by utilizing empty convention centers, for example, to care for those with mild or moderate disease and at low risk; an isolation infirmary for all patients will decrease transmission to family members. Convert now-empty hotels into quarantine centers to house those who have been exposed, and separate them from the general population for 2 weeks; this kind of quarantine will remain practical until and unless the epidemic has exploded in a particular city or region. Being able to identify the fifth group — those who were previously infected, have recovered, and are adequately immune — requires development, validation, and deployment of antibody-based tests. This would be a game-changer in restarting parts of the economy more quickly and safely.