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128. The marked reduction in the tuberculosis mortality in children under five is attributed to the vaccination of new-born babies with B.C.G. This practice, started in 1952, now has wide acceptance both by parents and by all agencies engaged in midwifery. In 1952 only 4.33% of new-born babies received B.C.G. but with increasing co-operation by all persons engaged in midwifery this has now risen to 81.59% of all births registered in 1962.

129. In the adult age groups, between 1952 and 1962, the average age of death from tuberculosis has risen from 25 years to 46 years, and this shift of mortality has been most obvious in relation to pulmonary disease which accounts for 87,9% of all tuberculosis deaths. During the same period, the total deaths from pulmonary tuberculosis have fallen by 32.7% and the change in the pattern is illustrated in Table 6 below.

All Ages Minus 32.7%

TABLE 6

AGE VARIATION IN TUBERCULOSIS MORTALITY 1952-62

(Expressed as percentage of 1932 figures)

Under 5 years

5-44 years

45-59 years Minus 96.5% Minus 61.2 Plus 20.7%

Over 60 Plus 130.3%

130. In addition to the ageing of the population of Hong Kong, there are two further factors which have a bearing on this situation. The first is that the introduction of effective chemotherapy is prolonging sub- stantially the life of patients with chronic fibro-caseous disease, and the other is the prevalence of the disease among the older people coming into Hong Kong from China.

Tuberculosis Morbidity

131. During the past decade, the annual notifications of cases suffer- ing from tuberculosis have varied in number between 12,000 and 15,000. The origin of such notifications during 1962 was as detailed in Table 7.

TABLE 7

NOTIFICATIONS OF TUBERCULOSIS (ALL AGES) 1962

Government Chest Clinics

10,691

Other Government Institutions

Tung Wah Group of Hospitals

1,680

NO1

Other Non-Government Institutions and Private Practitioners

1,091

14,263

132. The total of 14.263 notifications is some 1.679 more than that of the previous year and can be attributed to the large influx of immi. grants during the months of April and May and to the increasing co- operation by private practitioners in notification.

133. The morbidity rate of the disease, as measured by the ratio of notifications for each 100,000 of population, has declined from the peak figure of 689 in 1951 to 419 in 1962, the lowest figure have been 396 in 1961. As in the mortality figures, there has been a marked change in the age distribution of reported cases; since 1954, the incidence rate amongst children under five years of age has declined by 83.6%, while that for all persons over that age has fallen by only 15%.

134. The decline in the incidence of the disease in children under five is attributed to the increasing acceptance of B.C.G. vaccination. Despite the fact that a considerable proportion of these young children lose their tuberculin sensitivity within a period of two years after vac- cination, it does appear that some degree of protection nevertheless persists. In Hong Kong an investigation has shown that, in common with experience elsewhere, the actual drop in sensitivity over a period of 18 months amongst previously known reactors was 33%. Revaccina- tion with B.C.G. on entry to school is at present being considered and preliminary investigations regarding the procedures to be adopted, and their extent, are under way.

135. According to the notifications received, tuberculous meningitis in children under five has been slow to respond to control measures and it was thought that one reason may be that the total may have been inflated by errors in diagnosis. During the year a system of cross-checking of the notifications and the diagnosis was introduced, since when the total number of deaths recorded as due to tuberculous meningitis has Fallen from 165 to 79.

136. In the past, when an individual attended a Government Chest Clinic for the first time, no inquiries as to origin have been made. Early in 1962, it appeared that the proportion of patients recently arrived in the Colony who were attending had increased considerably and an investigation into the incidence of imported disease was started. From this survey it appeared to be reasonable to conclude that attendances at Chest Clinics were relatively heavy among those who had resided in the Colony for six months or less, and that among this group there was a greater proportion of extensive disease, and a higher proportion of drug resistant disease.

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