Conversion Rates of Tuberculin Test according to BCG Vaccination Methods

ABSTRACT

PURPOSE: Tuberculosis, a major public health problem, is an important cause of childhood morbidity and mortality in developing countries. To decline the tuberculosis morbidity rate, active BCG vaccination is performed worldwide. Recently percutaneous multiple puncture technique of BCG vaccination was introduced and used because of side effects of intradermal BCG vaccination such as scar, local ulceration, regional suppurative lymphadenitis. We studied the difference of positive conversion rates and side effect after intradermal BCG vaccination and percutaneous multiple puncture technique BCG vaccination. METHODS: Three hundred seventy one infants, who were vaccinated at well baby clinic of Soonchunhyang University Hospital and performed tuberculin skin test using 5TU PPD (NIH, Korea) at 4month, were divided two groups; group I of 257 infants immunized percutaneous multiple puncture technique BCG (Japan BCG Laboratory, Japan) and group II of 174 infants immunized intradermal BCG (Institute Meri ux, France). RESULTS: 1) Sixtysix point five percent of male infants and 72.4% of female infants were vaccinated percutaneous multiple puncture technique BCG (Group I) 2) The positive conversion rate was 97.7% in group I and 76.3% in group II (p<0.05). 3) The positive conversion rate vaccinated within 2 weeks after birth were 97.9%, 2-4weeks 97.8%, 5-6weeks 95.2% in group I, and within 2 weeks 73.5%, 2-4weeks 75.8%, 5-6weeks 83.3% in group II. 4) The mean induration of positive conversions were 10.6+/-2.8mm in group I and 9.3+/-2.7mm in group II, that of Group I was significantly higher than that of groupII (p<0.05). 5) The complications of BCG vaccination were fever, generalized rash, and local ulceration in group I, fever, severe irritability in groupII. But there was no significant difference in two groups. CONCLUSIONS: The infants of vaccinated with percutaneous multiple puncture technique showed larger size of mean induration and higher positive conversion rate after PPD and less scar after vaccination compared with intradermal method. Further studies is necessary to find out the optimum time for BCG vaccination by percutaneous multiple puncture technique to provide the better immunity.