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Published on: September 19, 2016
Neonatal BCG vaccination to prevent asthma: Results from the MIS BAIR randomized controlled trial
Laure F Pittet1,2,3, Emily K Forbes1, Susan Donath2,4
1Infectious Diseases Group, Murdoch Children's Research Institute, Parkville, Victoria, Australia.
Insights
Neonatal BCG vaccination showed a trend towards preventing asthma in children, though further research is needed to confirm these findings. This study explored BCG vaccine efficacy for allergy prevention.
Area of Science:
- Immunology
- Pediatrics
- Public Health
Background:
- Asthma is a global health concern with limited prevention strategies.
- Early-life immunity modulation is a potential avenue for asthma prevention.
Purpose of the Study:
- To evaluate the efficacy of neonatal BCG vaccination in preventing childhood asthma.
- To assess BCG vaccine's impact on early-life immunity for allergy prevention.
Main Methods:
- A phase 3 multicentre randomized controlled trial (Melbourne Infant Study: BCG for Allergy and Infection Reduction - MIS BAIR) was conducted.
- 1272 infants were randomized to receive BCG-Denmark vaccine or no intervention within 10 days of birth.
- Asthma incidence at 5 years was assessed using the International Study of Asthma and Allergies in Childhood (ISAAC) criteria.
Main Results:
- The adjusted incidence of asthma was 14.4% in the BCG group versus 16.0% in the control group (aRD -1.7%).
- Trends favored the BCG group for severe asthma (aRD -3.9%) and preventer medication use (aRD -5.6%).
- A lower asthma rate was observed in BCG-vaccinated children with asthmatic parents (17.6% vs 24.7%), though not statistically significant.
Conclusions:
- Point estimates suggest BCG vaccination may offer protection against asthma.
- Wide uncertainty intervals necessitate larger studies to confirm long-term benefits.
- Further research is required to validate BCG vaccination's role in asthma prevention beyond its established indications.
Background:
Asthma has a significant impact worldwide, but prevention strategies remain limited. We aimed to evaluate the efficacy of neonatal BCG vaccination in preventing asthma by modulating early-life immunity.
Methods:
The Melbourne Infant Study: BCG for Allergy and Infection Reduction (MIS BAIR) was a phase 3 multicentre randomized controlled trial in Victoria, Australia. Infants were randomly assigned to receive the BCG-Denmark vaccine or no intervention within 10 days of birth. The incidence of asthma at 5 years of age was estimated using the International Study of Asthma and Allergies in Childhood questions.
Clinicaltrial:
gov (NCT01906853).
Results:
A total of 1272 infants were randomized. The adjusted incidence of asthma was 14.4% in the BCG group compared to 16.0% in the control group (adjusted risk difference [aRD] -1.7 percentage points; 95%CI -7.4, 3.9). Secondary outcomes, including severe asthma and use of preventer medication, showed similar trends, with an aRD of -3.9 (95%CI -7.7, 0.0), and -5.6 (95%CI -10.9, -0.4), respectively, favoring the BCG group. Among participants with one or both parents asthmatic, the rate of asthma was also lower in the BCG group (17.6%) compared with the control group (24.7%; aRD -7.2; 95%CI -15.9, 1.5), although a test for interaction was not significant (p = .07).
Conclusions:
While the point estimates suggested BCG vaccination might protect against asthma, the wide uncertainty around the estimates means further studies with larger sample sizes are needed to evaluate the long-term benefits of BCG vaccination beyond its primary indication.
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