Use of purified protein derivative to assess the risk of infection in children in close contact with adults with tuberculosis in a population with high Calmette-Guerin bacillus coverage

Setting. Household contacts 10 mm. Positivity and induration sizes increased with age, although this was significant only in the controls. the presence of a BCG scar was not associated with having a positive PPD. the degree of exposure was an important factor for PPD positivity; 66 (60.6%) of the 109 children with close exposure were positive compared with 1 (3.1%) of 32 with less intimate exposure. PPD indurations among close contacts were also larger than those with restricted exposure and controls (16.3, 11 and 9.4 mm, respectively; P <0.05). PPD positivity was associated with the quantification of acid-fast bacilli in the adult; 38.5% of contacts with adults with sputum with (+) were positive, compared with 42.3% of those with (+ +) and 58.4% with (+ + +) (P < 0.05).Conclusion. PPD is a useful test to identify children infected with TB independently of whether they had received BCG or not. Children exposed to adults with TB are at high risk of infection. the risk of infection is associated with the intimacy of contact and the number of bacilli expectorated in sputum.Fed Univ Sergipe, Aracaju, BrazilUniv São Paulo, Fac Med Ribeirao Preto, Dept Pediat, São Paulo, BrazilLiverpool Sch Trop Med, Liverpool, Merseyside, EnglandWeb of Scienc