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Infant BCG vaccination study in Lithuania
E Suciliene1, T Rønne, A M Plesner
1Republican Hospital of Tuberculosis and Lung Diseases, Vilnius, Lithuania.
Insights
The Danish BCG vaccine induced stronger tuberculin reactions and larger scars when administered at 3 months versus at birth. Vaccination timing significantly impacts BCG vaccine efficacy in infants.
Area of Science:
- Immunology
- Vaccinology
- Pediatrics
Background:
- Bacille Calmette-Guérin (BCG) vaccination is crucial for preventing tuberculosis (TB) in infants.
- Evaluating different BCG vaccine strains and vaccination schedules is essential for optimizing TB prevention strategies.
- The Danish strain 1331 and the WHO International Reference Preparation (IRP) are commonly used BCG vaccines.
Purpose of the Study:
- To compare the immunogenicity of the Danish BCG vaccine (strain 1331) against the WHO IRP vaccine in neonates.
- To assess the impact of BCG vaccine dosage and age at vaccination on tuberculin reactivity and scar formation.
- To determine the optimal vaccination strategy for BCG in newborns.
Main Methods:
- A randomized four-armed study was conducted in Vilnius, Lithuania, involving neonates.
- Vaccination groups included: normal dose Danish vaccine at birth, half dose Danish vaccine at birth, normal dose IRP vaccine at birth, and normal dose Danish vaccine at 3 months.
- Tuberculin reactivity and scar formation were measured to evaluate vaccine efficacy.
Main Results:
- Vaccination with the Danish BCG vaccine at 3 months of age resulted in significantly larger tuberculin reactions and scars compared to neonatal vaccination.
- The WHO IRP vaccine showed borderline significantly larger reactions than the Danish vaccine.
- Reducing the Danish vaccine dose did not significantly alter reaction size, though smaller reactions were observed.
Conclusions:
- Administering the Danish BCG vaccine at 3 months of age enhances its immunogenicity, leading to stronger tuberculin responses and more prominent scars.
- The WHO IRP vaccine may elicit a stronger reaction than the Danish strain 1331.
- Vaccination timing is a critical factor influencing BCG vaccine effectiveness in infants, suggesting a potential benefit of delayed vaccination.
Setting:
Infants identified in maternity hospitals in Vilnius, Lithuania.
Objectives:
To test the capacity of the BCG vaccine, Danish strain 1331 (Danish vaccine), to induce tuberculin reactivity and scar formation in neonates compared to the WHO International Reference Preparation of BCG (IRP vaccine), and to study the effect of dose and of age at vaccination.
Design:
A randomized four-armed study: 1) normal dose, 0.05 ml Danish vaccine given to neonates at birth, 2) half the normal dose of Danish vaccine given at birth, 3) IRP vaccine given at birth at normal infant dose, and 4) the normal infant dose of Danish vaccine given at 3 months of age.
Results:
Larger tuberculin reactions, as well as an increased frequency and larger scars, were seen when Danish vaccine was given at 3 months of age in comparison to neonatal vaccination. Halving the dose resulted in smaller reactions, but the difference was not significant. The IRP vaccine resulted in borderline significantly larger reactions in comparison to the Danish vaccine. The number of infants receiving very early vaccination (0-2 days) was not evenly distributed in all groups, however, which is believed to explain the observed difference.