BCG vaccination reaction in low birth weight infants

About 30 per cent newborns (preterm and term) weigh < 2500 g at birth. The immunological system is less mature in low birth weight (LBW) babies compared to term and normal birth weight (NBW) babies. Bacille Calmettee Guerin (BCG) vaccine is given at birth under the national immunization programme. There is a paucity of information on the immunogenicity of BCG vaccine in preterm and LBW babies. It was, therefore, proposed to study the reaction of BCG vaccination in LBW, preterm and normal birth weight newborns.

A total of 143 newborns (90 term and 53 preterm; of these 78 were LBW) received during March to September 1998, 0.1 ml of BCG vaccine (Danish 1331 strain) intradermally on the left arm just above the insertion of the deltoid muscle within 7 days of life. At the same time trivalent oral polio vaccine was administered as per the national immunization programme. These babies were followed up in the immunization clinic at 4, 6, 8, 10 and 12 +/- 1 wk to observe reactions at the BCG vaccination site.

After 4 wk reaction at the vaccination site was significantly (P < 0.001) delayed in preterm babies as compared to term infants, and in the LBW babies (P < 0.05) as compared to NBW babies. The reaction at the site of vaccination was not found to be different at 6, 8, 10, 12 wk. BCG scar was seen in 47.5 per cent infants (45.4% in < 2500 g birth weight and 50% in > or = 2500 g birth weight infants) at 12 wk. But 33 (42.3%) LBW and 24 (36.9%) NBW infants also showed papule, pustule, ulceration or scab at the BCG vaccination site.

The BCG reaction was seen in the sequential order from papule to scar formation. No significant difference was seen in the scar formation in infants studied with varying gestation and birth weights after 12 wk of BCG vaccination. Fifty seven (40.4%) babies still showed different stages of BCG reaction at 12 wk. BCG vaccine along with OPV administered in early neonatal life showed successful BCG reaction in 95.5 per cent infants.