Testing, Voluntary Social Distancing, and the Spread of an Infection

A standard policy to reduce the spread of infection is increasing the use of testing that enables the isolation of infected individuals, slowing down the infection. In “Testing, Voluntary Social Distancing, and the Spread of an Infection,” the authors argue the possibility of unintended behavioral consequences from increased testing: greater testing reduces voluntary social distancing or increases social activity, exacerbating the spread of the virus. They show that the effect of testing on infections is nonmonotone. This nonmonotonicity also implies that the optimal testing policy may leave some of the testing capacity of society unused and that increasing testing should be used together with mandatory social distancing to reduce the spread of infection. We study the effects of testing policy on voluntary social distancing and the spread of an infection. Agents decide their social activity level, which determines a social network over which the virus spreads. Testing enables the isolation of infected individuals, slowing down the infection. However, greater testing also reduces voluntary social distancing or increases social activity, exacerbating the spread of the virus. We show that the effect of testing on infections is nonmonotone. This nonmonotonicity also implies that the optimal testing policy may leave some of the testing capacity of society unused. Funding: The authors acknowledge support from C3.DTI funding. Supplemental Material: The online appendix is available at https://doi.org/10.1287/opre.2021.2220 .