OPTIMAL VACCINATION STRATEGIES FOR A COMMUNITY OF HOUSEHOLDS

The effectiveness of a vaccination program depends on how the vaccinat ions are spread over the households of the community. Here we formulat e the optimal allocation of vaccinations as a linear programming probl em, when the objective is to prevent epidemics with the minimum vaccin ation coverage. A vaccine efficacy of less than 100%, as is usual in p ractice, is allowed for. Optimal vaccine allocations attempt to leave the same number of susceptibles in every household if the disease has a very high transmission rate within households. This means that propo rtionately more individuals need to be vaccinated in larger households if the vaccine efficacy is <100%. The linear programming formulation can accommodate heterogeneity among individuals of the proportionate m ixing form and can also minimize the initial reproduction number for a given achievable vaccination coverage. (C) Elsevier Science Inc., 199 7