Clinical features and outcomes of Bacille Calmette-Guérin (BCG)-induced diseases following neonatal BCG Tokyo-172 strain immunization

Background: Bacille Calmette-Guérin (BCG) vaccination at birth may cause mild and benign local adverse effects (AE). More serious AE are rarely reported.

Objective: To describe clinical features and outcomes of BCG (Tokyo-172 strain)-induce diseases (BCG-ID) that required medical attention at a tertiary care center in Bangkok, Thailand.

Method: We retrospectively reviewed medical records from January 2007 to December 2016 that were selected by ICD-10 codes. The inclusion criteria were the patients under 3 years of age who developed lymphadenitis, osteitis, or disseminated infections of which BCG was a possible pathogen. Cases were classified into suspected (clinically compatible without laboratory confirmation), probable (suspected cases with M. tuberculosis complex identified), and confirmed BCG-ID (probable cases with molecular confirmation of M. bovis BCG strain).

Results: 95 children were identified; 57 (60.0%) were male, and the median age at presenting symptom was 3.5 (range: 0.6-28.7) months. Of these, 25 (26.3%) were suspected, 49 (51.6%) were probable, and 21 (22.1%) were confirmed BCG-ID. Overall, 87 (92%) children had regional lymphadenitis corresponding to the BCG site, 5 (5%) had osteitis, and 3 (3%) had disseminated BCG. Of those with lymphadenitis, average size was 2.2 (range 0.7-5) cm. in diameter and 53% (46/87) had pulmonary involvement. Five children with immunodeficiency; three had disseminated BCG and two had lymphadenitis. Eight (9.2%) patients with lymphadenitis underwent needle aspiration; 57 (65.5%) had surgical excision. All children with BCG osteitis underwent surgical intervention in combination with anti-tuberculosis treatment. One patient with osteitis experienced long-term leg length discrepancy.

Conclusion: Regional lymphadenitis was the most common feature of BCG-ID requiring medical attention. That none of the BCG osteitis were immunocompromised hosts suggested the potential virulence of BCG in neonates. A systematic national surveillance and reporting system is needed to develop accurate estimates of population incidence and support development of effective vaccine policy.