Outbreak of Bacille Calmette-Guérin-related lymphadenitis in Saudi children at a university hospital after a change in the strain of vaccine.

Background And Objectives: Bacille Calmette-Guérin (BCG) vaccination is part of the expanded program of vaccination in Saudi Arabia. Lymphadenitis is the most common complication of the BCG vaccine. We observed an increase in the rate of BCG lymphadenitis that coincided with the introduction of a new strain of BCG vaccine.