To TST or not to TST: is tuberculin skin testing necessary before BCG immunisation in children?

Area of Science:

• Immunology
• Vaccinology
• Public Health

Background:

• Bacille Calmette-Guérin (BCG) is a widely used vaccine, often administered at birth in high tuberculosis (TB) prevalence areas.
• In low TB prevalence regions, BCG is used as a travel vaccine for children, necessitating pre-vaccination screening for latent TB infection (LTBI).
• Screening for LTBI via tuberculin skin test (TST) before BCG is recommended to prevent accelerated local reactions and avoid unnecessary vaccination in already infected individuals.

Purpose of the Study:

• To review and discuss current international guidelines on pre-BCG immunisation screening for LTBI in children.
• To highlight the significant variations and lack of evidence underpinning these guidelines.
• To propose an alternative strategy for targeted LTBI screening.

Main Methods:

• Systematic review and discussion of international guidelines and recommendations.
• Analysis of age-related cut-offs and selection criteria for LTBI screening.
• Proposal of a risk assessment questionnaire as an alternative screening method.

Main Results:

• Current international guidelines for pre-BCG LTBI screening in children exhibit significant variation.
• Lack of robust evidence contributes to the inconsistencies in age-related cut-offs and selection criteria.
• A risk assessment questionnaire approach is proposed to optimize screening.

Conclusions:

• Current guidelines for pre-BCG LTBI screening in children are inconsistent due to limited evidence.
• A risk-based questionnaire strategy can reduce unnecessary TSTs while identifying children needing evaluation for LTBI.
• Targeted screening ensures appropriate management for children with LTBI before BCG vaccination.