The Response of Mantoux Test after BCG Vaccination According to the Clinical Factors.

Lee, Hyun Jung; Kim, Young Hoon; Lee, Joon Sung; Whang, Kyung Tai

Abstract

PURPOSE
During the childhood, Mantoux test is very popular for detecting tuberculous infection and also useful for evaluating the immunity against tuberculosis after BCG vaccination. But the response and conversion rate is affected by the age of vaccination, the quality of vaccine, the duration after vaccination and the frequency of the test. This study was performed to investigate the difference of the response and conversion rate, according to duration after vaccination, gestational age, sex and feeding type.
METHODS
The subject was included 85 of infants (71 of full term infants, 14 of preterm infants) and was followed up 3 months, 9 months, 15 months after vaccination, from July, 1992 to June, 1994 in Kangnam St. Mary's Hospital. We injected intradermally the BCG vaccine (0.05ml) which was produced by National Institute of Health and PPD (5TU) was used as a testing material of Mantoux test. Injecting BCG and interpreting the result of the Mantoux test was done by the same person.
RESULTS
1) The positive conversion rates of Mantoux test which was done 3 month, 9 month and 15 month after vaccination were 26.8%, 53.5% and 60.6% in the full-term infant group, and 14.3%, 28.6%, and 50% in the preterm infant group. The conversion rate was significantly lower in preterm infant group as compared with that of the full-term infant group 3 months after vaccination. 2) The sizes of induration in Mantoux test, which was done 3 month, 9 month and 15 month after vaccination, are 7.2mm, 8.5mm, 9.4mm in the full-term infant group and 5.0mm, 6.6mm, 8.2mm in the preterm infant group. The size of induration was significantly lower in the preterm infant group as compared with that of the full-term infant group. 3) There is no difference in conversion rate of Mantoux test according to the sex, feeding type in both groups. 4) Complication rate for BCG vaccine is 9.9%, which is leaded by lymphadenitis, persistent ulcer, and febrile abscess as the order, in the full-term infant group and there are no complications in the preterm infant group.
CONCLUSIONS
In those results, the size of induration and conversion rate is increased as the duration after vaccination, then lower conversion rate in the preterm infant group 3 months after vaccination may be due to immunological immaturity of preterm infant.