摘要Objective:To investigate whether there is an association between diameter of bacilleCalmette-Guérin(BCG) scars and effect of purified protein derivative(PPD) reaction and to determine whether vitaminA(VA) combined vitaminD(VD) supplementation influences the immune response toBCG revaccinated inChinese infants.Methods:A cross-section and3-month community-randomised trial was conducted.A total of5629 infants at3,6 and12 months of age inJunanCounty ofChina were examined forBCG scar formation.Then,597 revaccinated infants were randomly assigned to supplementation(n=307) and control(n=290) groups.The supplementation group were daily assigned to1500IUVA and500IUVD for3 months.Then all infants were subjected to skin test withPPD.Results:The diameter ofBCG scars was positively correlated with diameter of skin indurations ofPPD(r=0.17,P<0.05) in the5629 infants.The rate of positive response toPPD was higher in the supplementation group than in the control group (96.1% versus89.7%,P<0.05, prevalence ratio1.07,95%CI1.02-1.12).The prevalence ratio ofPPD response for the supplementation group compared with that for the control group was1.07(95%CI1.01-1.13) for the males and1.08(95%CI1.00-1.17) for the females.For the supplementation group, the males got larger tuberculin induration than the females [(0.73±0.21) cm versus(0.67±0.20) cm, P<0.05) after intervention.Conclusions:The diameter ofBCG scars was effectively correlated withPPD response, which indicatesBCG scar formation may be an useful tool to evaluate the effect of tuberculosis prevention.VA combinedVD supplementation may play an immuno-regulatory role inBCG revaccination.This may contribute to the prevention of childhood tuberculosis.