Implications of Test Characteristics and Population Seroprevalence on “Immune Passport” Strategies

Various forms of “immune passports” or “antibody certificates” are being considered in conversations around reopening economies after periods of social distancing. A critique of such programs focuses on the uncertainty around whether seropositivity means immunity from repeat infection. However, an additional important consideration is that the low positive predictive value of serological tests in the setting of low population seroprevalence and...