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BCG Vaccine-associated Complications in a Large Cohort of Children With Combined Immunodeficiencies Affecting
Waleed Al-Herz1,2, Entesar H Husain1, Mehdi Adeli3
1From the Department of Pediatrics, Faculty of Medicine, Kuwait University, Kuwait City, Kuwait.
Insights
Bacillus Calmette-Guérin (BCG) vaccination complications occurred in 18.1% of combined immunodeficiencies (CID) patients, with lower CD8+ counts increasing risk. Health authorities should consider screening and delaying BCG vaccination.
Area of Science:
- Immunology
- Vaccinology
- Pediatrics
Background:
- Combined immunodeficiencies (CID) are genetic disorders affecting immune system development and function.
- Bacillus Calmette-Guérin (BCG) vaccination is contraindicated in patients with CID due to the risk of severe complications.
- Despite contraindications, BCG vaccination is administered to some CID patients, necessitating an understanding of associated risks.
Purpose of the Study:
- To detail the incidence and characteristics of BCG-vaccine associated complications (VACs) in patients diagnosed with combined immunodeficiencies (CID).
- To identify risk factors and clinical patterns of BCG-VACs in this vulnerable population.
Main Methods:
- A retrospective study involving five centers.
- Data collection included patient demographics, clinical information, laboratory results, and vaccination history.
- Analysis focused on identifying factors associated with BCG-VAC development in 236 CID patients.
Main Results:
- 127 out of 236 CID patients received BCG vaccination; 18.1% developed BCG-VACs.
- Complications occurred at a median age of 6 months, with a median onset of 6 months post-vaccination.
- Lower CD8+ T-lymphocyte counts (≤250 cells/µL) were identified as a significant risk factor for BCG-VACs on multivariate analysis.
- Localized complications appeared earlier (median 4 months) than disseminated ones (median 7 months).
Conclusions:
- BCG vaccination continues to be administered to CID patients despite contraindications.
- Low CD8+ T-cell count is a risk factor for BCG-related complications.
- Recommendations include implementing newborn screening, delaying BCG vaccination beyond 6 months, and using safer BCG strains (Danish, Tokyo).
Aims:
To present the details of Bacillus Calmette-Guérin (BCG)-vaccine associated complications (VACs) in combined immunodeficiencies (CID) patients.
Methods:
Five centers participated in this retrospective study and completed a data form, which included general patients' information, clinical and laboratory data.
Results:
Among 236 CID patients, 127 were BCG vaccinated. 41.9% of patients with family history of CID and 17.1% who were diagnosed by screening were BCG vaccinated. Twenty-three patients (18.1%) developed BCG-VACs. The median age of VACs was 6 months and the median time from vaccination to complications was 6 months. The highest rate of BCG-VACs was recorded in patients receiving the Russian BCG strain compared to the Tokyo and Danish strains. Univariate analysis of T-lymphocyte subsets showed increased odds of BCG complications in patients with CD3+, CD4+, and CD8+ counts of ≤250 cells/µL. Only CD8 + count ≤250 cells/µL had increased such odds on multivariate analysis. VACs were disseminated in 13 and localized in 10 patients. Localized complication occurred earlier after vaccination (median: 4 months) compared with disseminated ones (median: 7 months). There were no significant associations between sex, administered vaccine strain, serum immunoglobulins levels, lymphocyte subsets counts, and the chance of having either localized or disseminated BCG-related complications.
Coclusions:
Although contraindicated, many patients with CID continue to be vaccinated with BCG. Low CD8 + count is a risk factor for BCG-related complications and localized complications occurred earlier than disseminated ones. Considerations should be undertaken by health care authorities especially in countries with high incidence of CID to implement newborn screening, delay the time of BCG vaccine administration beyond 6 months of age and to use the relatively safer strains like the Danish and Tokyo ones.
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