Clinical features of tuberculosis and Bacillus Calmette-Guérin (BCG) -associated adverse effects in children: A 12-year study

Purpose: To investigate the clinical feature of tuberculosis and BCG adverse effects in children and to examine whether delayed BCG vaccination changes the incidence of BCG osteomyelitis. Methods: We analyzed patients younger than 18 years with tuberculosis or BCG-associated adverse effects from 2008 to 2019. We compared their clinical features, laboratory tests and outcomes. Results: Totally 137 patients were collected, with 27% of pulmonary tuberculosis (PTB), 31% of extrapulmonary tuberculosis (EPTB) and 42% of BCG-associated adverse effects. The median age was older in PTB than EPTB group (17.1 vs 15.4 years; p = 0.015). More patients in EPTB group had fever than PTB group (55% vs 25%; p = 0.008). Compared with exclusively EPTB, more patients in EPTB plus PTB group had fever (78% vs 38%; p = 0.009), and had more systemic symptoms (67% vs 25%; p = 0.007), lower absolute lymphocyte count (1230 vs 1850/μL; p = 0.033), higher CRP level (5.62 vs 2.21 mg/dL; p = 0.024) and longer hospital stay (20 vs 11 days; p = 0.031). In BCG osteomyelitis group, the median time interval from vaccination to diagnosis was 16.4 months (IQR 15.0–20.2). Age at vaccination, either at birth or 5-8 month-old, did not affect the proportion of BCG osteomyelitis among children with BCG-associated adverse effects. Conclusion: Children with EPTB plus PTB had more fever, lower lymphocyte count and higher CRP. The median time interval from vaccination to diagnosis of BCG osteomyelitis was 16.4 months and the proportion of BCG osteomyelitis among children with BCG-associated adverse effects was not affected by delayed vaccination in this study.