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Delaying BCG vaccination from birth to 10 weeks of age may result in an enhanced memory CD4 T cell response

Benjamin M N Kagina1, Brian Abel, Mark Bowmaker

  • 1South African Tuberculosis Vaccine Initiative (SATVI), Institute of Infectious Diseases and Molecular Medicine and School of Child and Adolescent Health, University of Cape Town, Cape Town, South Africa.

Vaccine
|July 21, 2009
PubMed

Insights

Delaying the bacillus Calmette-Guérin (BCG) vaccine from birth to 10 weeks enhances infant immune responses. This delayed vaccination leads to improved T cell responses against tuberculosis (TB) at one year of age.

Area of Science:

  • Immunology
  • Vaccinology
  • Pediatrics

Background:

  • Bacillus Calmette-Guérin (BCG) is a crucial vaccine for preventing severe tuberculosis (TB) in infants, typically administered at birth.
  • The neonatal immune system is not fully mature at birth, potentially limiting the efficacy of early-life vaccinations.

Purpose of the Study:

  • To investigate whether delaying BCG vaccination from birth to 10 weeks of age improves the vaccine-induced immune response in infants.
  • To compare the quantitative and qualitative T cell responses between infants receiving BCG at birth versus at 10 weeks of age.

Main Methods:

  • A randomized clinical trial was conducted where infants received BCG intradermally at either birth (n=25) or 10 weeks of age (n=21).
  • Vaccine-specific CD4 and CD8 T cell responses were assessed using a whole blood intracellular cytokine assay at 10 weeks post-vaccination and at 1 year of age.

Main Results:

  • Infants receiving delayed BCG vaccination showed significantly higher frequencies of BCG-specific CD4 T cells.
  • Polyfunctional T cells, co-expressing IFN-gamma, TNF-alpha, and IL-2, were notably increased in the delayed vaccination group.
  • These enhanced T cell responses were most pronounced when measured at 1 year of age.

Conclusions:

  • Delaying BCG vaccination to 10 weeks of age enhances both the quantity and quality of BCG-specific T cell responses.
  • The findings suggest that a delayed BCG vaccination schedule may lead to a more robust and sustained immune response against tuberculosis in early childhood.
Abstract

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