Measures to decrease contact between persons during an influenza pandemic have been included in pandemic response plans. We used stochastic simulation models to explore the effects of school closings, voluntary confinements of ill persons and their household contacts, and reductions in contacts among long-term care facility (LTCF) residents on pandemic-related illness and deaths. Our findings suggest that school closings would not have a substantial effect on pandemic-related outcomes in the absence of measures to reduce out-of-school contacts. However, if persons with influenzalike symptoms and their household contacts were encouraged to stay home, then rates of illness and death might be reduced by approximately 50%. By preventing ill LTCF residents from making contact with other residents, illness and deaths in this vulnerable population might be reduced by approximately 60%. Restricting the activities of infected persons early in a pandemic could decrease the pandemic's health effects.