Tuberculin Response of Ethiopian Children After BCG Vaccination at Birth
Creators: name: Mebratu, Abebe
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 1993

description: In an attempt to evaluate the effectiveness of neonatal BeG vaccination policy, a tuberculin survey was conducted among different age groups of children in Lideta awraja, Addis ababa who had received BeG vaccination shortly after birth. The survey consisted of assessing the immunization records and nutritional status and conducting clinical histories and physical examinations. Thereafter, each study subject's site of BeG vaccination on the right shoulder was assessed and the size of the scar graded. Tuberculin PPD tests were also performed simultaneously, and were read within 96-120 hours. tuberculin reaction A standard data collection form was used to record address, age, sex, body weight, BeG Scar and tuberculin response. In addition, 60 children were revaccinated at the age of 10 years (within the study period) and tuberculin tests were performed 2 months after the second vaccination. Furthermore, 70 bacteriologically proven tuberculosis patients were also tuberculin tested at the beginning of the study, in order to check the potency of tuberculin PPD test and to estimate the diagnostic value of the test. A total of 895 children were studied between October 1992 and February 1993. Of these 563 (63%) had a definite BeG scar while the rest 331 (37%) were without a Scar. The sex distribution in each group was similar. The percentage of tuberculin non reactors in different age groups was 39.5% at 2 months, 34.5% at 18 months, 39.1% at 5-7 years, and 46% at 9-11 years. The number of tuberculin non reactors initially showed a slight decline from age 2 months and then an increase from age 18 months onward; the overall pattern of induration si ze was vi statistically significant different between the age groups (P&lt; 0.001). Some 55% of the children without a BeG scar showed no response to the tuberculin test, while 67% of those with a scar showed a positive tuberculin response. A direct correlation was observed between tuberculin reactivity and the size of BeG scar (P6 mm) was observed in 11% of children despite the absence of the BeG scar . Children without the BeG scar have 2.53 times the risk of a negative tuberculin those with a BeG scar (P 4 mm). The tuberculosis patients showed tuberculin reactions according to an unimodal distribution. Of these 12% showed 10 -15mm induration. A reaction of 10-15 mm were also observed in 3.3% of children without a scar,ll% of children with a large scar size( &gt;5mm) and in 10% Of revaccinated children with out tuberculosis infection. This revealed that the lack of specificity of the test. Overall, this finding emphasized the poor tuberculin response in infants at the age of 2 months compared to 18 months after vaccination at birth and the waning effect of tuberculin response at the age five years compared to 18 months. It indicates that the BeG induced allergy tended to disappear in this age group and the need for revaccination. Thus we suggest a further study in deciding the age of first vaccination and revaccination at the age of 5 years without tuberculin test. In estimating coverage of vaccination, the presence of BeG scar used as an indicator may overestimate by almost a factor of two . Hence for accurate estimates we recommend determining the rate of tuberculin reactors in populations who have a BeG scar.