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The decline of BCG immunity after neonatal vaccination: what about revaccination at one year?

H Aydinlioglu1, S Caglayan, S Kansoy

  • 1SSK Tepecik Teaching Hospital, Izmir, Turkey.

Paediatric and Perinatal Epidemiology
|July 1, 1993
PubMed

Insights

BCG vaccine immunity wanes over time in newborns, dropping from 87% to 61% reactivity by 12 months. Revaccination ensures 100% reactivity, and scar presence indicates immunity.

Area of Science:

  • Immunology
  • Pediatrics
  • Public Health

Background:

  • The Bacillus Calmette-Guérin (BCG) vaccine is crucial for preventing tuberculosis (TB) in newborns.
  • Understanding the duration and indicators of BCG vaccine-induced immunity is vital for public health strategies.

Purpose of the Study:

  • To assess the persistence of tuberculin reactivity after BCG vaccination in healthy newborns.
  • To evaluate the effectiveness of revaccination in nonreactive infants.
  • To explore the correlation between BCG vaccination scar formation and tuberculin reactivity.

Main Methods:

  • A cohort of 219 healthy newborns received the BCG vaccine.
  • Tuberculin reactivity was measured at 3, 6, and 12 months post-vaccination.
  • Scar assessment was performed on the left deltoid region.

Main Results:

  • Tuberculin reactivity decreased from 87% at 3 months to 61% at 12 months.
  • Revaccination of infants who were not reactive to tuberculin resulted in a 100% reactivity rate.
  • A strong correlation was observed between tuberculin reactivity and the presence of a BCG vaccination scar.

Conclusions:

  • BCG vaccine-induced immunity, as indicated by tuberculin reactivity, wanes significantly within the first year of life.
  • Revaccination is effective in restoring tuberculin reactivity.
  • BCG scar formation serves as a reliable indicator of a child's immunity to tuberculosis, potentially simplifying post-vaccination monitoring.

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