Complications de la revaccination par le BCG : 12 observations

Abstract

Calmette-Guérin bacillus (BCG) is a live attenuated strain used in tuberculosis vaccination. Local and systemic side-effects, although rare, are associated with BCG vaccine. They are common in cases of overdose and with poor vaccination techniques. These complications also occur in some cases of revaccination. This was a retrospective study over a period of 5 years between January 2000 and March 2005. 12 patients presenting complications following revaccination with BCG were observed. Patients were revaccinated with BCG following a negative intradermal reaction test. The following parameters were recorded: age, gender, history, vaccination method, type of complication, treatment and outcome. There were 10 men and 2 and women of mean age 21 years (19 to 23 years). Mean time to consultation was 4 weeks. Complications comprised subcutaneous abscess in 8 cases, deep chronic ulcers in 4 cases complicated by humeral osteitis in one case. The dose administered was 0.1 ml in 9 patients and 1 ml in 3 others (i.e. 10 times the recommended dose). Six patients had extensive and progressive ulceration, with one positive culture, the presence of a granuloma with caseum necrosis and one case of humeral osteitis, and specific treatment was given. Revaccination is no longer recommended by the WHO since efficacy is considered to be low or even nil. Intradermal injection is the reference method for BCG vaccination. Technical errors such as injection of an excessively high dose of the vaccine or subcutaneous administration of the vaccine solution increase the incidence of adverse effects. In our study, three patients erroneously received 1 ml of vaccine and the injection was too deep in 9 cases. There are few reports in the literature concerning the underlying mechanisms of these post-revaccination accidents; two major physiopathological mechanisms, infectious and immunological, are discussed. There is no consensus regarding treatment of these complications. Six of the 12 patients received specific therapy for 6 months.