Optimal Targeted Lockdowns in a Multigroup SIR Model

We study targeted lockdowns in a multigroup SIR model where infection, hospitalization, and fatality rates vary between groups—in particular the “young,” “middle-aged,” “old.” Our enables tractable quantitative analysis of optimal policy. For baseline parameter values for COVID-19 pandemic applied to US, we find that policies differentially targeting risk/age groups significantly outperform uniform most gains can be realized by having stricter protective measures such as on more vulnerable, old group. Intuitively, strict long lockdown both reduces infections less lower-risk groups. (JEL H51, I12, I18, J13, J14)