BCG vaccination of children against leprosy: fourteen-year findings of the trial in Burma.

The value of BCG vaccination in preventing leprosy among children was studied in an area of high leprosy endemicity in Burma through a controlled trial; one group of 13 066 children received BCG and another group of 13 176 served as controls. The overall protective effect of BCG, which was only about 20% over the 14-year period, was found to vary with the batch of vaccine, as well as age, sex, and contact status of the children. BCG protection was found to be independent of the initial tuberculin status of the children. The protective effect of BCG against the lepromatous type of leprosy could not be measured because of the low incidence. Protection was observed throughout the fourteen years of the study except for the first year. The results are compared with those of three other major BCG trials in leprosy. The trial has shown that BCG provides only a very modest level of protection and that BCG vaccination is not likely to be an important solution for leprosy control.

Sensitivity to tuberculin and to a nonmammalian sensitin in Mandalay District, Burma.

Delayed hypersensitivity that can be demonstrated with either a strong dose of tuberculin or a conventional dose of a sensitin prepared from certain nonmammalian mycobacteria (mycobacteria of Runyon Groups II and III, e.g., Mycobacterium avium), is known to be highly prevalent in most tropical and many subtropical areas and rare in many temperate zones. Whether such sensitivity interacts significantly with tuberculosis or with leprosy is not known.A study of reactions to tuberculin (PPD-S) and to a sensitin prepared from M. intracellulare (PPD-B) was carried out in villages close to an area in which a clinical trial of the preventive effect of BCG against leprosy was being conducted. The population had not been vaccinated with BCG. Some of the villages were in river valleys that become flooded every year for a long period during the rainy season; others were on slopes above the area subject to floods. The findings showed that sensitivity to the nonmammalian sensitin was prevalent in the area, and thus confirmed previous findings of low-grade tuberculin sensitivity in Burma and neighbouring countries. No difference in this prevalence was found between flooded and nonflooded villages.

Site of early skin lesions in children with leprosy.

Most of the data on the site of early skin lesions in leprosy were obtained from the case histories of registered patients, mainly those in leprosy institutions and who had had the disease for one or more years. Such information should be treated with reservation. The purpose of this study was to determine, in a highly endemic area, the site of early skin lesions in 28 220 children who, after screening, were kept under close surveillance and re-examined yearly. In 469 patients with a single lesion, this was most often located on the thighs or buttocks, followed by the arms, forearms, legs, and lumbar region. This finding is of interest mainly for diagnostic purposes. The predilection of single early lesions for certain regions of the body does not appear to depend on whether these parts are exposed or not.

Late lepromin reaction in untreated patients with indeterminate leprosy under 21 years old in Burma.

Studies on lepromin reactivity in indeterminate (I) leprosy have usually been carried out among patients in whom the disease appeared 1 or more years before testing. This may result in misleading findings because a high proportion of patients, probably those showing moderate or strong lepromin reactions, seem to progress to the tuberculoid pole of leprosy in a relatively short time (<1 year), and in many the lesions heal spontaneously. The object of the present study was to determine the frequency and intensity of late lepromin reactions (macroscopic readings) in untreated I patients aged under 21 years who had had the disease for less than 1 year. Of 209 patients tested with lepromin containing 160 x 10(6) bacilli/ml only a small proportion ( not equal 7%) showed a negative or doubtful lepromin reaction, while 61.5% were 2+ and 3+ reactors. These findings indicate that a favourable outcome may be expected in most I cases in the trial area.

Correlation between leprosy rates in villages different distances apart.

In order to study the role of genetic factors in susceptibility to leprosy infection, the prevalence of leprosy in 118 pairs of Burmese villages different distances apart was investigated. The distribution pattern of the correlation coefficients for leprosy rates was compared with that known to occur for genetic markers under similar conditions. The correlation coefficients decreased rapidly as the distance between the pairs of villages increased and then showed periodicity with distance, becoming negative at almost regular intervals of 4 km: negative values were preponderant for villages more than 25 km apart. Thus with this set of correlations it was not possible to fit a monotonically decreasing function of the type that would fit similar data for a genetic marker

BCG vaccination of children against leprosy: seven-year findings of the controlled WHO trial in Burma.

A controlled study of the efficacy of BCG vaccination for the prevention of leprosy began in Burma at the end of August 1964. This paper presents the findings after 7 years-i.e., the results of 6 annual follow-up examinations up to the end of June 1971. The incidence rate in BCG-vaccinated children 0-4 years of age at intake was lower than that in children in the control group. The protection conferred by BCG was relatively low (44%) and applied only to early cases of leprosy, the great majority tuberculoid cases. BCG vaccination did not protect household contacts or children 5-14 years of age who were not exposed in the household. This reduction must be interpreted in the light of several factors: form of leprosy, bacterial status, lepromin reactivity, evolution of cases, and level of endemicity. Consequently it does not seem probable that the reduction in incidence would substantially affect the pattern or trend of the disease in an area similar to that where the study is being carried out; the probability would be much lower if not nil in regions of relatively low endemicity (1-2 per 1 000 or less).