Enhancing effect of tuberculin allergy as a result of repeat tests with 1 TU RT 23 on groups tested with I TU, 20 TU and placebo was studied by random allocation among population not vaccinated with BCG in 8 villages. In all, 2357 persons were tested with 1 TU and 759 with normal saline at first round. Based on testing at three rounds the study population could be divided into eight different groups and were labelled with alphabets 'a' to 'h' having been tested once, twice or thrice. The groups 'a', 'c', 'e' & ’g' were tested at 2 months, round two with 1 TU RT 23 and remaining half were not tested. However, all available persons in the 8 groups were retested at the third round, 18 months after the initial test. Thus, eight groups cannot be treated as independent samples but representative of the whole population.

The study did not show enhancing effect due to previous tuberculin test with 1 TU alone among groups tested once, twice or thrice after an interval of 18 months. Part of population was tested with 20 TU at round one; boosting effect was seen at 2 months when test was repeated. However, it was not seen after 18 months but when exactly the boosting effect disappeared was not known. Thus, there was no increase in reaction even among those who were tested with a higher dose of 20 TU earlier after 18 months. The groups provided the largest number for comparison between tested and the control groups. It is inferred from the study that boosting with high dose or repeat tests with the same dose does not persist after 18 months. Hence, for classifying positive tuberculin reactors, no correction is required to the same individuals/population after an interval of 18 months or more, as no boosting effect after 18 months has been observed, on the basis of this analysis.

Five districts in which short course chemotherapy (SCC) was introduced during 1987-88 (DTP-SCC) and an equal number of districts without an SCC programme (DTP-SR) but having comparable new sputum examinations performance (NSE) in 1986 were selected from the states of Gujarat and Tamilnadu. Data obtained by the monitoring cell of the National Tuberculosis Institute (NTI) for 15 consecutive quarters from the lst quarter of 1986 were analysed. It was possible to study operational variables: NSE, number of pulmonary patients diagnosed (TBP) and number of bacillary cases detected (BCASE). While the figures of first six quarters were used to represent pre SCC performance, those of the last six quarters depicted the post SCC scenario. However, the trend analysis has been done using the whole data.

The growth rates of NSE, TBP and BCASE were 14.1%, 1.7% and 13.0% respectively for DTP-SCC compared with 17.0%, 5.3% and 29% for DTP-SR. Both the DTCs and PHIs in DTP-SR showed negative growth in BCASE, inspite of their efforts as evidenced by increase in NSE and TBP, the introduction of SCC led to an increase in BCASE for both DTC and PHIs. While the PHIs in DTP-SCC showed increased efficiency in all the aspects (NSE 24.4%, TBP 19%, BCASE 16.7%), DTCs showed decreased activity in NSE ( -2.4) and TBP (-6.6%), indicating improvement at the periphery. Trend analysis corroborated the above findings.