The devastation wreaked by the COVID-19 pandemic spurred innovations in technology and public policy. Many countries rushed to implement extensive quarantines, and some introduced disease surveillance, including location tracking to enforce quarantines. Though the United States has never implemented high-tech quarantine surveillance, such technology will certainly be available for the next disease outbreak.
Absent significant doctrinal change, the Fourth Amendment likely bars some, but not all, forms of quarantine surveillance. Quarantine surveillance probably constitutes a Fourth Amendment “search” that generally must be backed by probable cause. This probable cause requirement, and its subcomponent of individualized suspicion, likely applies differently to different kinds of surveillance programs. In targeted programs—say, only surveilling individuals who are sick—the government would, before surveilling an individual, have evidence unique to that individual that would justify heightened caution. This could constitute probable cause. But en mass surveillance—say, surveilling all citizens of a town—would lack individualized evidence, being based on the broad danger posed by the disease. The Fourth Amendment likely demands, at a minimum, that quarantine surveillance programs be tightly restrained: targeting only those people who pose a distinct, individualized danger to public health.