Tuberculosis Among Elderly Persons: An Outbreak in a Nursing Home

Abstract

An epidemic of tuberculosis among elderly residents of a nursing home was caused by the presence of a highly infectious patient (sputum smear positive) for at least 12 mo. Forty-nine (30%) of 161 previously tuberculin-negative residents (mean age, 73.5 yr) became infected; 8 (17%), developed progressive primary tuberculosis, including 1 who died. Of 138 tubercluin-negative employees 21 (15%) were infected, of whom 1 (5%) developed clinical tuberculosis. The epidemic was finally stopped by giving preventive treatment with isoniazid to all converters, despite their advanced ages. Only 3 of 39 patients so treated manifested toxicity that subsided on withdrawal of isoniazid. The fraction of elderly persons harboring a dormant tuberculous infection today is smaller than generally thought. If one of this group develops active tuberculosis, however, it may endanger 80%-90% of fellow residents and employees. Tuberculin reactors showed a significant protection against developing tuberculosis from exogenous reinfection.