policies of chemotherapy in Hong Kong showed that an initial period of six months of three drugs is no more effective than an initial period of three months of three drugs, and the results were presented at the 21st International Tuberculosis Conference at Moscow. The study also showed that expensive routine pre-treatment sensitivity tests, were not as essential as previously believed, and should not be used on a routine basis. Investigations of international interest were carried out with regard to second-line drugs, and a belief prevailed that the problems of drug toxicity associated with second line drugs could be overcome so that these drugs could be given without the present initial period of hospitalization.
49. The joint study with the World Health Organization, namely the Comparative Study of Different Techniques of giving B.C.G. Vaccination to newborn infants in Hong Kong, continued on a follow- up basis. During the year, a new survey was begun of children born on or after 11th July, 1966, and notified as suffering or dying from tuber- culosis. In this connection, the collaboration of the Medical Research Council Statistical Research and Services Unit was obtained. In certain parts of the world, direct B.C.G. is given to children of school age and a study to evaluate its role in Hong Kong came under planning. Another study, also under planning, was related to the differentiation between tuberculin positivity due to B.C.G. and that due to tuberculosis, or infection with atypical myco bacteria.
Case Finding
50. In the past, the many patients attending the chest clinics made large scale case-finding undesirable. With improved facilities and the decrease in the number of patients, case-finding during the year came to play an increasingly important role. Emphasis was placed in 1971 on symptom-motivated patients, and health education techniques were used to ensure a proper understanding of the discase. The chest unit participated in the Fisheries Exhibition at Aberdeen from 14th to 19th February, 1972.
Mortality and Morbidity
$1. During the year, there was a marked fall in the tuberculosis death rate from 36.3 to 30.9. The majority of deaths continued
14
to occur in elderly males who had been suffering from tuberculosis for many years, and who died of its sequelae rather than from active tuberculosis. Tuberculosis mortality by age and sex is shown in Figure 5.
JEIMI PLA SEDE HUSKATS IN MNE Mont
FIGURE 3
TUBERCULOSIS MORTALITY BY AGE & SEX
1961 AND 1971
T
WALMA
FORMLC P
52. Also during the year, the notification rate fell to 223.2 per 100,000 of the population. Figure 6 shows the changes which have taken place in age and sex specific notification rates. There were marked reductions in the incidence of the disease during childhood. There was little change in the vulnerability of adolescents, and some reduction in the incidence of the disease among middle-aged adults. The high susceptibility of males, except in childhood, corresponded with the patterns recorded elsewhere in the world.