Re-introduction of selective BCG programme needed, study suggests

The findings of a recent Trinity College study support the introduction of a selective Bacillus Calmette-Guérin (BCG) vaccine programme in Ireland to prevent severe paediatric tuberculosis (TB).

Researchers from the university's School of Nursing and Midwifery This study retrospectively analysed TB notifications aged 0–6 years old reported to the Irish National TB Surveillance System between 2011 and 2021.

Ireland had a universal BCG programme between 1949 and 2013, when it became an opt-in programme. The vaccine was discontinued entirely in Ireland in 2015 due to lack of supply. In 2022, a selective BCG vaccination strategy was published but this is not yet operational.

Key epidemiological characteristics and temporal trends in TB age specific incidence rates (ASIRs) were compared between 0 and 6 year old cases born during a period of universal BCG vaccination (2007–2015) and 0–6 year old cases born after BCG vaccination ceased (2015–2021).

The researchers found the epidemiology of cases in both birth cohorts remained similar. While this study did not find a significant increase in paediatric TB cases aged 0-6 years old, interruption of the previously declining trend in this age group during universal vaccination may be an early warning of a future increase.

Modelling studies conducted elsewhere suggest that full effects of moving from universal to selective programmes may take up to 15 years to emerge. 

According to the study's authors, the findings emphasise the need for timely surveillance of paediatric TB cases to monitor for the emergence of increasing trends or emergent risk groups in this mainly unvaccinated population, and to evaluate the longer-term effects.

Robust systems for the identification of, and service delivery to, populations being targeted by the selective programme are also needed to enable sufficient vaccination uptake and ensure a selective policy does not result in a practice of no vaccination, according to the authors.

The research was published recently in the journal Vaccine.