Although the foregoing studies have indi¬ cated considerable variation in the average an¬ nual reactivation rate, a variation that could be related both to differences in the definitions of a case and in the living conditions of the study populations, all agreed that the risk of reactivation was substantial. And yet there is surprising variation in the period of observa¬ tion recommended for persons with inactive pulmonary tuberculosis. Some health depart¬ ments do not advise any followup of persons with newly diagnosed minimal inactive disease; others advise periodic examinations for 5 years or longer. Such variation in public health practice suggested the need for further infor¬ mation on the importance of relapses among persons with inactive.
