Tuberculin Skin Testing in San Francisco Schools, 1956-1966: an Epidemiologic Analysis

¹ Assistant Director, San Francisco Health Department and Director, Chest Clinic, San Francisco General Hospital

1. An epidemiologic analysis of tuberculin skin testing in San Francisco schools for the ten-year period 1956-1966 was presented.

2. There were 310,563 students tested, of whom 13,059 (4.2 per cent) were positive reactors. All positive reactors and their immediate family group were examined. A total of 542 cases of tuberculosis were discovered: 356 in students and 186 in family contacts. The case finding rate was 41.7 per 1,000 reactors found.

3. Prevalence rates and trends in students are better indices of the tuberculosis problem in the community and the effectiveness of the control program.

4. The effect of the BCG immunization and atypical mycobacterial infections in the community upon the prevalence rates in students has been discussed.

5. Whereas 85.1 per cent of the students with disease were non-whites and Latin Americans, 97 per cent of the tuberculous students resided in the older and poorer sections of the city. The geographic distribution of cases by place of residence indicates that the economic level of families is as important an epidemiologic factor in the spread of infection and the development of clinical disease as racial or ethnic background.

6. Two-thirds of the positive reactors found during the last two years have been among students new to San Francisco schools and at the first grade level. It is estimated that by modifying the program to these two groups, 95 per cent of the cases found in the present school program would be discovered.