BCG vaccination of full-term infants with chronic intrauterine malnutrition: influence of immunization age on development of post-vaccination, delayed tuberculin hypersensitivity

Abstract

To determine the effect of intrauterine growth retardation (IUGR) on the response to BCG vaccination, we evaluated the specific delayed tuberculin hypersensitivity of 57 full-term infants with symmetric IUGR (SGA or small for gestational age) and 52 full-term infants with normal intrauterine growth (AGA or appropriate for gestational age). The infants were evaluated using post-vaccination skin tests to tuberculin purified protein derivative (PPD) and tuberculin lymphocyte transformation tests. Using a positive response to the skin test as an indicator of delayed hypersensitivity, we found that the rate of response to BCG in the SGA and AGA groups was similar. A total of 65% of infants with IUGR responded to BCG vaccination. The response rate among SGA infants who were vaccinated at 5 days of age, about 26 days of age (weight > or = 2500 g), 3 months of age, and 6 months of age was 68%, 47%, 69%, and 88%, respectively. The overall response rate for infants with no IUGR was 71%; the rate response to BCG vaccination among this group was 52% (those vaccinated at 5 days of age), 90% (3 months of age), and 80% (6 months of age). Our data suggest that the immunogenicity of BCG vaccine is similar in term infants who have normal or abnormal intrauterine growth and the presence of IUGR should not be a reason for delaying BCG vaccination.

PIP: In Brazil, pediatricians followed 109 infants born at the University Hospital of Ribeirao Preto in Sao Paulo every 2 weeks for 3 months and then at 6 months to examine the effect of intrauterine growth retardation (IUGR) on the response to BCG vaccination. They used a tuberculin purified protein derivative to determine tuberculin hypersensitivity and a lymphocyte transformation test to determine lymphocyte proliferation to tuberculin 12-14 weeks after vaccination. The rate of response to BCG in the IUGR infants was basically the same as that of infants whose weight was appropriate for gestational age (AGA) (65% vs. 71%). Specifically, the rate among IUGR infants vaccinated at 5 days old, once they weighed at least 2500 gm (around 26 days old), 3 months old, and 6 months old was 68%, 47%, 69%, and 88%, respectively. The rate among AGA infants vaccinated at 5 days old, 3 months old, and 6 months old was 52%, 90%, and 80%, respectively. The results indicated that BCG vaccination was more immunogenic as the infants aged than when they were newborns, regardless of intrauterine status. They demonstrated that waiting to administer the BCG vaccination when the IUGR infants weighed 2500 gm had no advantage over administering the vaccination when they were newborns. In developing countries with a high prevalence of tuberculosis, such a delay would place these especially vulnerable infants at greater risk of tuberculosis.