<p>Results: Among 380 case-persons, 206 (54.2%) were male, mean age was 19.3 years (SD=12.6); none died. The attack rate (AR) at NTC was higher among exiting persons (3.8%) than entering persons (0.6%) (p&lt;0.0001). Among 42 cases and 127 controls, close contact with symptomatic persons (aOR=9.6; 95%CI=3.1-30) increased odds of infection; having a face mask (aOR=0.06; 95% CI=0.02-0.17) decreased odds. We observed overcrowding in shelters, poor ventilation, and most NTC residents not wearing face masks.</p>