Sensitivity to PPD tuberculin and M. scrofulaceum sensitin in schoolchildren BCG vaccinated at birth.

OBJECTIVE: To determine the degree of and variation in sensitivity to PPD RT 23 tuberculin and M. scrofulaceum sensitin RS 95 at school age in children BCG vaccinated at birth. DESIGN: Double-testing by applying standard WHO Mantoux tests and inspecting BCG scars. SETTING AND PARTICIPANTS: Urban and rural schools in Southwest Finland, 1091 children aged 11-13 years. MAIN OUTCOME MEASURES: Size of tuberculin and sensitin indurations and BCG scar (mm). RESULTS: The mean size of tuberculin indurations was 7.2 mm, sensitin indurations 8.1 mm and BCG scars 7.9 mm. The reaction to sensitin was significantly larger than to tuberculin (95% confidence interval 0.58-1.10 mm) and the zero reactions to sensitin were fewer. Correlation between tuberculin and sensitin indurations was significant (r = 0.75, 95% confidence interval 0.72-0.77). There were induration greater than or equal to 15 mm to tuberculin in 16% and to sensitin in 14%. Sensitin indurations exceeded those of tuberculin by 4 mm or more in 14% of the children with at least 5 mm tuberculin indurations. CONCLUSIONS: High tuberculin sensitivity in healthy schoolchildren may be partially maintained by contact with environmental mycobacteria. Our data do not prove but very probably indicate that children have protective immunity. In view of the current incidence of tuberculosis in Finland and the likelihood that lymph node infections and sensitivity to environmental mycobacteria will increase, continued BCG vaccination at birth is recommended.

The annual tuberculosis infection rate, the tuberculin survey and the tuberculin test.

In the present stage of development where tuberculosis mortality has lost its statistical significance because of effective chemotherapy, it is generally recognized that the most reliable measure of the extent of the tuberculosis problem in a population is the "annual tuberculosis infection rate" or incidence of infection. In countries where infection with the bovine type of tubercle bacilli no longer exists, as is the case in the majority of low prevalence countries, the annual infection rate expresses that proportion of the population under study which will be primarily infected, or reinfected with tubercle bacilli from a human source in the course of one year. The annual tuberculosis infection rate is also the best measure for following the trend of the tuberculosis problem in a given population and for evaluating the total effects of organized efforts to control tuberculosis.

[Non-specific tuberculin sensitivity in school children in European countries]. / Nichtspezifische Tuberkulin-Hautempfindlichkeit bei Schulkindern in europäischen Ländern.

In a prospective study in the Netherlands running since 1965 and in a multinational cooperative study of the International Union Against Tuberculosis and Lung Disease (IUATLD) carried out in 13 countries the question was examined to which extent and trend non-specific tuberculin sensitivity in Europe exist. It could be proved that schoolchildren living in countries with a coastline show non-specific tuberculin sensitivity to a greater extent than children in other countries. The prevalence-trend is to be checked up by follow-up studies. Exact knowledge about geographic distribution of non-tuberculous mycobacteria and about extent and trend of diseases induced by non-tuberculous mycobacteria are necessary to assess their importance in Europe.

Report of a study into skin sensitivity and into scar diameter after vaccination with BCG in 5,000 new-borns in Cakovec, Yugoslavia.

To compare the skin allergy producing potency of batches of BCG from three different production centers, 5,066 new-borns were vaccinated with one of there batches (one from the Netherlands, one from Yugoslavia and one from Denmark). Six, twelve and twenty-one months after vaccination tuberculin testing was done and the diameter of scars was measured in subgroups. Skin allergy through BCG-vaccination was registered to be highest after 6 months and appeared to wane rapidly afterwards. There was a definite difference in the skin allergy potency between the three vaccines. The difference in scar diameter was less pronounced. In 5,066 vaccinated new-borns 137 (2.7%) enlarged axillar glands were registered. There appeared to be a positive correlation between the mean Mx-induration 6 months after vaccination and the percentage of enlarged glands. No serious complications have been registered so far.

The persistence of tuberculin sensitivity following oral BCG vaccination in The Netherlands.

Certain anomalies in the tuberculin test results in Netherlands schoolchildren in the late 1960s and in recruits a few years later are shown to have arisen from the persistence of tuberculin sensitivity in some of the 10 000 newborn children who were given oral BCG vaccine in the early 1950s. More than 90% of these oral BCG vaccinations were given in 1950 or 1951 in Amsterdam, Delft or Hilversum, but because of the absence of a scar or any record, individuals who were vaccinated cannot now be distinguished from the much larger numbers of unvaccinated subjects. The cohorts of Dutch children born in 1950 and 1951 showed excess positivity, compared with earlier and later cohorts, when tuberculin tested at different ages in adolescence and as army recruits, and this was especially noticeable among current residents in these three cities. It is estimated that less than 10% of those given oral BCG vaccine in the Netherlands in 1950 or 1951 showed positive reactions at ages 12 and 13, but about 20% did at age 16, and about 45% at age 18. A review of data on tuberculin sensitivity several years after intradermal BCG vaccination in the newborn or in young children suggests that sensitivity persists in only a relatively small proportion for a long period (in perhaps about 45% after 7 years and less after a longer period), unless boosted by intervening tuberculin tests. The present data on oral BCG vaccination in the newborn conform to the same pattern.(ABSTRACT TRUNCATED AT 250 WORDS)

The risk of tuberculous infection in The Netherlands from 1967 to 1979.

Estimates of the annual risks of tuberculous infection in the Netherlands from 1910 to 1966 were made by Stýblo et al. [1] from tuberculin surveys in recruits and schoolchildren. The risk decreased particularly steeply after about 1940 (the annual decrease in log risk was about 13%), and forward projections of the risk were made on this basis to 1980. Tuberculin test results in male recruits and in secondary or primary schoolchildren between 1966 and 1979 have now been used, alone and in conjunction with the earlier material, to estimate the trend in the risk of tuberculous infection in the Netherlands up to 1979, and to study the sex and age patterns in the risk. The risk of infection has continued to decrease steeply with calendar year in the Netherlands. Among the recruits the log risk, estimated only from the data from 1966 to 1979, decreased annually by 10.4%, compared with the estimate of 13.7% from the earlier data from 1956 to 1966; this difference is non-significant. Analysis of the complete data on schoolchildren from 1956 to 1979 shows a decrease in their log risk of infection of 15.0% each calendar year. The risks of infection were similar for boys and girls up to age 10, but were higher for boys than for girls (by 10.2%) during adolescence. In addition there was an increase in log risk of about 6.1% for each year of age up to age 20. According to this analysis, the annual risks of tuberculous infection in 1979 in the Netherlands were estimated to be 6, 9, 12, and 16 in 100 000 boys aged 5, 10, 15 and 20 years respectively, and 6, 9, 11 and 15 in 100 000 girls.