BCG vaccine scars tied to decline in infant mortality
Scarring caused by bacillus Calmette-Guérin, or BCG, vaccine in both mothers and infants was associated with a significant decrease in infant mortality, according to findings from a randomized controlled trial published in the Journal of the Pediatric Infectious Diseases Society. The researchers wrote that the effect of the tuberculosis vaccine on mortality was not as strong when only the child had scarring.
Previous research has demonstrated the benefits of some live vaccines, including BCG, on child survival by “enhancing protection against nontargeted infections.”
“BCG scars are strong markers of a correctly administered BCG vaccination, and they indicate that the immune system has been trained to provide some protection against non-TB diseases,” Peter Aaby, DMSc, a professor at the Bandim Health Project, told Infectious Diseases in Children.“When the mother also has a BCG scar, BCG vaccination of the child will provide additional protection against non-TB disease. Priming from the mother may be very important for how the child responds to a vaccination, and this is not taken into consideration in current practice.”
The researchers enrolled almost 6,500 children aged 4.5 months in a trial that focused on early measles vaccination. The children received follow-up until age 36 months. Aaby and colleagues compared the morality rate ratios of children according to whether the mother, child or both had a BCG scar.
The researchers focused on 2,213 children who did not receive neonatal vitamin A supplementation or early measles vaccination. They identified BCG scarring in 83% of these children and 44% of mothers. Children whose mothers had BCG scarring were more likely to have BCG scarring themselves (risk ratio = 1.01; 95% CI, 0.98-1.05).
Children who had BCG scarring had a 41% (95% CI, 5%-64%) lower mortality rate between the ages of 4.5 and 36 months. The researchers calculated that children had a 66% (95% CI, 33%-83%) lower mortality rate if their mothers also had BCG scarring, but those born to mothers without scarring had only an 8% (95% CI, –83% to 53%) decrease in mortality (P = .04).
“Mother-and-child health programs should monitor the BCG scar status of both mother and child,” Aaby said.
He added that individuals residing in areas where BCG is used, including Guinea-Bissau, who do not have a BCG scar should be revaccinated.
“This is not happening at the moment and could have major effects on child survival,” he said. “Pediatric wards might use a lack of BCG scar to identify high-risk children.”
Berendsen MLT, et al. J Pediatr Infect Dis Soc. 2019;doi:10.1093/jpids.piy142.
Source: Healio
