[Incidence and prevalence of positive tuberculin skin test reactions among schoolchildren.].
OBJECTIVE
To investigate the incidence and prevalence of positive tuberculin skin test reactions in schoolchildren from six to 16 years of age.


METHODS
Data from tuberculin test school surveys in Reykjavik during the years 1958 to 1991 are available for almost all individuals of each age cohort. During 1958 to 1991 schoolchildren from six to 16 years of age were tested annually. In Iceland regular BCG vaccination in children or aldults has never been applied.


RESULTS
Incidence of positive tests in all ages fell from 2.5 (per 1000 tested per year) from 1958 down to 0.5 in the mid seventies and after that the incidence remained low. Prevalence of positive tests for the same age group in different age cohorts showed that for each age group from seven to 16 years positive tests were most common at the beginning of the study period but decreased successively to the beginning of the seventies. The prevalence of positive tests was low and almost unchanged during 1976 to 1991 and varied from 0 -1.6 (per 1000 tested per year) among children seven to eight years of age, 0-2.9 among children 11 to 12 years of age and from 0-3.8 among those aged 15 to 16 years.


CONCLUSIONS
During the last decade little has been gained by systematic testing for tuberculosis as a tool for finding newly infected persons or carriers of M. Tuberculosis. It seems to us that the results of this study do not justify systematic testing for tuberculous infection in all schoolchildren. Increased emphasis should be placed on testing among risk groups such as immigrants from countries where tuberculosis is endemic. Recent infection due to M. Tuberculosis is a high risk factor for tuberculosis. Search for newly infected persons in close contact with infectious patients with tuberculosis should have priority next to the diagnosis and treatment of the patients. Tests for tuberculosis among those who want to immigrate to Iceland circumscribe another risk group where containment of tuberculosis is possible.
Gunnbjornsdottir
M I
MI
Blondal
T
T
Briem
H
H
Olafsson
O
O
Jakobsdottir
S
S