How long does the immune response last after BCG vaccination?
Author Information
Author(s): Weir Rosemary E, Gorak-Stolinska Patricia, Floyd Sian, Lalor Maeve K, Stenson Sally, Branson Keith, Blitz Rose, Ben-Smith Anne, Fine Paul E M, Dockrell Hazel M
Primary Institution: London School of Hygiene & Tropical Medicine
Hypothesis
What is the duration of the immune response induced by BCG vaccination in adolescents?
Conclusion
BCG vaccination in infancy and adolescence induces immunological memory that can be measured for at least 14 years, although the response magnitude decreases over time.
Supporting Evidence
- Responses to the BCG vaccine were significantly higher than those of unvaccinated controls.
- 14 years after infant vaccination, 74% of vaccinees had detectable immune responses.
- Responses to mycobacterial antigens were maintained better than to control antigens.
Takeaway
When kids get the BCG vaccine, their bodies remember how to fight off tuberculosis for a long time, even up to 14 years later, but the strength of that memory gets weaker over time.
Methodology
A randomized control study tested adolescents for immune responses at multiple time points after BCG vaccination.
Potential Biases
Some participants may have been vaccinated for reasons that could influence immune response, such as family history of tuberculosis.
Limitations
The study had a small sample size for some comparisons and potential confounding factors related to travel history and ethnicity.
Participant Demographics
The study included 148 adolescents, 53% male, predominantly Caucasian (83%), with some Black, Asian, and mixed race participants.
Statistical Information
P-Value
0.012
Confidence Interval
95% CI 1.5–18.3
Statistical Significance
p<0.05
Digital Object Identifier (DOI)
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