OBJECTIVE: The incidence of tuberculosis (TB) has begun to rise again in the world in recent years. Reseachers have focused mainly on treatment for TB but have seldom studied on protective effect of vaccination of bacillus calmette guerin (BCG) on children. The aim of this study was to investigate the protective duration and impact of vaccinating children with BCG. METHODS: The BCG scar rate and positive purified protein derivative (PPD) rate were studied in 9 608 children who were vaccinated in both the urban and rural areas of Xianning City and who ranged in age from 0 to 14 years. RESULTS: The positive PPD rate of the children between 3 months and 1 year was the highest ( 91.5% ); it was the second highest in children ranging from 1 to 3 years ( 81.6% ), the lowest in children ranging from 3-7 years ( 57.1% ) and rose again in children ranging from 7-14 years ( 74.2% ) (P< 0.01 ). The positive PPD rate of the urban children was higher than that of the rural children ( 78.8% vs 62.4% ); the positive BCG scar rate of the urban children was 90.3% , higher than that of the rural children ( 56.1% ) (P< 0.01 ). The inciderce of natural TB infection in urban children was lower than that of the rural ones ( 1.7% vs 3.4% ). The incidence of natural TB infection in the children between 3 months to 3 years old was higher than those of the children raning from 3-7 years and 7-14 years. It was the highest in the children ranging fro 7 to 14 years.CONCLUSIONS: The protective effect of the BCG vaccination on 0-3 year old children is significant, but reduces on children of 4 years of age or older. The positive PPD rate and BCG scar rate of the urban children were higher than those of the rural children, indicating that the quality of vaccination of BCG should be improved in rural areas."/>
卡介苗接种对儿童结核病预防保护作用的探讨
Abstract：OBJECTIVE: The incidence of tuberculosis (TB) has begun to rise again in the world in recent years. Reseachers have focused mainly on treatment for TB but have seldom studied on protective effect of vaccination of bacillus calmette guerin (BCG) on children. The aim of this study was to investigate the protective duration and impact of vaccinating children with BCG. METHODS: The BCG scar rate and positive purified protein derivative (PPD) rate were studied in 9 608 children who were vaccinated in both the urban and rural areas of Xianning City and who ranged in age from 0 to 14 years. RESULTS: The positive PPD rate of the children between 3 months and 1 year was the highest ( 91.5% ); it was the second highest in children ranging from 1 to 3 years ( 81.6% ), the lowest in children ranging from 3-7 years ( 57.1% ) and rose again in children ranging from 7-14 years ( 74.2% ) (P< 0.01 ). The positive PPD rate of the urban children was higher than that of the rural children ( 78.8% vs 62.4% ); the positive BCG scar rate of the urban children was 90.3% , higher than that of the rural children ( 56.1% ) (P< 0.01 ). The inciderce of natural TB infection in urban children was lower than that of the rural ones ( 1.7% vs 3.4% ). The incidence of natural TB infection in the children between 3 months to 3 years old was higher than those of the children raning from 3-7 years and 7-14 years. It was the highest in the children ranging fro 7 to 14 years.CONCLUSIONS: The protective effect of the BCG vaccination on 0-3 year old children is significant, but reduces on children of 4 years of age or older. The positive PPD rate and BCG scar rate of the urban children were higher than those of the rural children, indicating that the quality of vaccination of BCG should be improved in rural areas.
