THE FLUCTUATION OF THE TUBERCULIN REACTION IN DIFFERENT GEOGRAPHIC AREAS AND ITS RELATIONSHIP TO RESISTANCE

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Abstract
In a 10-yr. study of induction, persistence, fluctuation and reversion of tuberculin reactivity, it was found that BCG-vaccinated Indians did not attain as great a percentage of persistent high degree tuberculin as did controls; that BCG-vaccinated subjects who did develop a high degree of tuberculin sensitivity showed decrease in reactivity or reversion to negativity in greater percentage than controls; that fluctuations and reversions[long dash]in both vaccinated and control subjects[long dash]occurred most frequently among persons living in the Pima Agency, Arizona. Apart from other considerations about the variability and actual variations of tuberculin reactivity, it is thought there must be special reasons for the greater variability and variations that were found in the Arizona reservation. Climatic factors, such as excessive sunshine, may be involved.