Tuberculin response two years after BCG vaccination at birth.
One hundred and forty nine Asian children who received BCG vaccine shortly after birth were reviewed at the age of 22 months. Many of them had an apparently inadequate response to the vaccine. A quarter had no scar, and half of the children with a scar had a negative response to 10 TU (Mantoux 1/1000) and these children showed only limited lymphocyte transformation in vitro in response to tuberculin. Various measurements of health at age 22 months suggested the Mantoux negative children were less privileged than the Mantoux positive ones, but the differences were not striking and most were not significant. It seemed more likely that the high incidence of poor response was due to some factor operating in the perinatal period. There was circumstantial evidence implicating perinatal nutrition, and there is a theoretical possibility of interference with vaccination by maternal antibody.