Hypothesis: What is the Best We Can Do with Hydroxychloroquine for COVID-19?

There are widespread anecdotal reports of seemingly successful treatment among the early (three to seven days from symptoms) stage coronavirus disease 2019 (COVID-19) patients with the drug hydroxychloroquine (HCQ), and randomized placebo-controlled trials of HCQ in outpatient settings are underway. In this note, we (1) report observational evidence and present scientific reasoning as to why early treatment with HCQ may succeed while treatment later in the disease progression is likely to fail and (2) hypothesize a public health regime under which HCQ may be used to mitigate the impact of the current pandemic.