Introduction
The Bacille Calmette-Guérin (BCG) vaccine, as the only available vaccine
against Mycobacterium Tuberculosis, is recommended by the World Health
Organization (WHO) in numerous countries (1, 2). According to the
expanded program of immunization (EPI) in Iran, all children receive BCG
vaccination at birth. BCG is derived from live attenuated Mycobacterium
Bovis and there are possible local, regional or systemic complications
following the vaccine injection (2, 3). The strain of the BCG vaccine,
the child’s immune response, and injection technique especially dosage
and administration route are considerable factors for the development of
the possible complications (4, 5). Mycobacterial infection is the most
common culprit for cold abscess, known as an abscess without severe
inflammation. The abscess also can be a result of incorrect
intramuscular BCG vaccine injection (6, 7). Here, we report three cases
of BCG-induced cold abscess as a result of erroneous injection of
vaccine into the infant’s thigh muscle.