An estimation of the scope for BCG vaccination in preventing tuberculosis among those aged 15–19 years in England and Wales at the present time

Abstract

The second report of the Medical Research Council trial of tuberculosis vaccines in adolescents (Medical Research Council, 1959) contained an estimate of the benefit to be expected from BCG vaccination. If all those tuberculin-negative on entry to the trial in 1950–52, at the age of 14 years, had been vaccinated with BCG, the reduction in the incidence of tuberculosis in the ensuing five years would have been 59 per cent. The present study, by taking into account the recent decrease in risk of exposure to tuberculous infection in England and Wales, provides similar estimates of the scope for BCG vaccination, which are more up to date and also applicable to the whole country. Of the tuberculosis notifications among those aged 15–19 years in England and Wales in 1958, it is estimated that 52 per cent could have been prevented by BCG vaccination at the age of 14 years of all who were then tuberculin-negative. This estimate for 1958 is compared with that for 1953, which was 60 per cent. There has thus been a moderate decline in the scope for BCG vaccination during these five years. If the trend in exposure to tuberculous infection continues, BCG vaccination of all tuberculin-negative children who are aged 14 years now (1959) would apparently reduce the incidence when they become 15–19 years of age by rather less than half. In terms of the numbers of cases preventable by BCG vaccination of children aged 14 years, the scope has declined very considerably, from about 2,950 notifications among those aged 15–19 years in 1953, to 1,400 in the same age group in 1958. We may in a few years reach a situation in this country in which mass vaccination of older school children prevents only small numbers of cases of tuberculosis in adolescents. If, however, the protection from vaccination is maintained, cases will also be prevented in those aged 20 years and over. It is estimated that the official scheme for BCG vaccination at the age of 13 years, which started at the end of 1953, reduced the numbers of notifications at ages 15–19 years in England and Wales by 50 in 1956, 156 in 1957 and 241 in 1958. These small numbers are due to incomplete coverage of the 15–19 year age group in these years and the slow development of the scheme. It is suggested that a central bureau should be established to collect and interpret the information in connexion with the official vaccination scheme. This could make a valuable contribution to the eradication of tuberculosis from this country.