This study found a high prevalence of RW in infants from a low-income population during the first year of life with the disease starting very early in their lives, progressing with more frequent episodes and being significantly associated to PN, particularly in the first 6 months of life.

The significant protective effect of exclusive breast feeding against pneumonia in this cohort and the evident role of recurrent wheezing as risk factor for pneumonia during the first year of life support the implementation or reinforcement of public policies encouraging exclusive breastfeeding and an adequate management of wheezing since the first months of life.

The aim of this study was to determine the tuberculin skin test (TST) response to three different BCG modalities [0.1 ml Tokyo (n=104), 0.05 ml Pasteur-Mérieux (n=137) and 0.1 ml Pasteur-Mérieux (n=100)] in a cohort of healthy newborns 5 months after vaccination at birth in Santiago, Chile. Among the 341 infants, 91.2% had a response to TST, and the mean+/-SD TST reaction size was significantly larger in infants receiving the Tokyo strain than in those receiving the 0.05 ml or 0.1 ml Pasteur-Mérieux strains (4.4+/-2.0, 3.5+/-1.3 and 3.1+/-1.4 mm, respectively; P<0.0001). The mean+/-SD of the BCG scar size was significantly lower in infants vaccinated with the Tokyo strain than in those vaccinated with the 0.1 ml Pasteur-Mérieux strain (3.9+/-1.2 vs. 4.3+/-1.1 mm; P=0.03) and no significant difference was found between infants receiving the Tokyo strain and the 0.05 ml Pasteur-Mérieux strain. However, the differences in TST size induced by diverse BCG vaccination modalities may not reflect the quality of the immunologically induced response in terms of TB protection.