Prevention of Acute Respiratory Infection in Taiwanese Institutionalized Elderly

The purpose of this study is to assess the efficacy of Bacille Calmette-Guérin (BCG) vaccination compared to placebo against acute respiratory infections in the elderly who are less protected by standard vaccines against influenza than other age groups. The investigators hypothesize that BCG vaccination can reduce incidence of infection and severity of a range of acute respiratory infections. Patients who are residents of participating long-term care facilities (LTCFs), who agree to participate in the study, or with a legal guardian who agrees on their behalf, will be randomly assigned to receive BCG vaccination or a placebo. Participants will be followed for up to six months to assess the incidence of infection and the severity of a range of acute respiratory infections.