When Does Catholic Social Teaching Imply a Duty to be Vaccinated for the Common Good?

In 2017, Carson and Flood outlined a general duty to be vaccinated, arguing from Catholic social teaching on justice, love, solidarity and the common good. This necessarily relied on assumptions about the typical nature of vaccination, assumptions which do not always hold true in concrete situations. I identify twelve criteria that, where they hold, strengthen the particular duty to be vaccinated, and, if not met, weaken or reverse it. These pertain to the biological agent which vaccination aims to protect against, the vaccine and its supply, the costs and benefits of vaccination to the individual and society, and the alternative courses of action. The two-way relationship between the moral duty to be vaccinated and vaccine mandates is discussed. Individuals and policy-makers need to know these criteria - and be provided the necessary information to evaluate vaccination against them - in order to make a truly rational judgement.