Related Experiment Videos
[Tuberculin reaction in healthy infants vaccinated with BCG at birth]
J Mallol1, G Girardi, A Quezada
1Servicio de Broncopulmonares, Hospital Infantil, Dr. Exequiel González Cortés.
Insights
A tuberculin test found only 8.8% positive reactions in BCG-vaccinated infants, suggesting potential issues with vaccine efficacy in the region. Further evaluation of BCG vaccine effectiveness is recommended.
Area of Science:
- Immunology
- Pediatrics
- Public Health
Context:
- BCG vaccination is a primary strategy for tuberculosis prevention in infants.
- Evaluating vaccine efficacy is crucial for public health interventions.
- Previous studies in similar populations reported higher positive tuberculin test rates.
Purpose:
- To assess the tuberculin reactivity in BCG-vaccinated infants under two years of age.
- To compare findings with previous research on BCG vaccine efficacy.
- To investigate potential factors affecting BCG vaccine effectiveness.
Summary:
- A tuberculin test using PPD RT-23 (2 TU) was administered to 228 BCG-vaccinated infants with no known tuberculosis exposure.
- A low positive reaction rate (8.8%) was observed, with a significant percentage (14.9%) showing negative reactions and absent BCG scars.
- These results differ from prior studies, indicating a potential need to re-evaluate current BCG vaccine efficacy.
Impact:
- Highlights potential variability in BCG vaccine effectiveness across different preparations or populations.
- Underscores the importance of ongoing surveillance and evaluation of vaccine performance.
- Informs public health strategies for tuberculosis control and prevention.
Abstract:
Tuberculin test with PPD RT-23 with Tween 80 (2 TU strength), was performed to 228 infants under two years of age. None of them had any history of contact with tuberculosis. All were healthy, well-nourished infants, and had been vaccinated with BCG at birth. A positive PPD reaction (greater than 6 mm), was found only in 8.8%, of them and 16.2% had no BCG scar on examination; 14.9% of the studied infants had negative PPD (0-5 mm) reactions together with absent BCG scars. These findings are significantly different from those previously reported by chilean authors, which showed higher proportion of positive (greater than = 6 mm) reaction to 2 TU PPD in infants from similar populations that had been vaccinated with different BCG preparations than our patients. These results suggest the need to evaluate the efficacy of the BCG vaccines that are currently being used in our country to determine the factors that may affect it and the protection that they afford.