Disease Precautionary period
Chickenpox (varicella) Until lesions are crusted and no new lesions appear
Herpes zoster (disseminated) Duration of illness
Herpes zoster (localized in immunocompromised patient) Duration of illness
Measles (rubeola) Smallpox Duration of illness
Tuberculosis (pulmonary or laryngeal, confirmed or suspected) Depends on clinical response; patient must be on effective therapy, be improving clinically (decreased cough and fever and improved findings on chest radiograph), and have three consecutive negative sputum smears collected on different days, or TB must be ruled out