Tokyo-172 BCG Vaccination Complications, Taiwan

To the Editor: BCG (Mycobacte-rium bovis BCG) is a vaccine for preventing childhood tuberculosis (TB), especially military and meningeal TB. Because Taiwan has an annual TB incidence rate of ≈70 cases/100,000 persons, the National Immunization Program has included neonatal BCG vaccination since 1965. The coverage rate has remained at 97% since 2001. According to the Taiwan Tuberculosis Registry, the median rate of TB infections diagnosed in patients <10 years of age during 2005–2007 was 0.39% (60 cases) (1). The risk of developing childhood extrapulmonary TB without lung involvement is highest among children <5 years of age. In 1965, the World Health Organization registered freeze-dried Tokyo-172 seed lot as an international reference vaccine strain (2). Tokyo-172 BCG is currently used in Taiwan, Japan, and South Korea. The vaccine is recommended as less reactogenic. Because intradermal injection is recognized as a more effective BCG administration route (3), it is practiced in Taiwan, while a multiple puncture method is used in Japan and South Korea. In addition, 10% BCG (Danish strain) vaccinations for infants are ad-ministrated intracutaneously in South Korea (4). Although BCG is effective in preventing progressive primary TB, adverse reactions to the vaccine do occur. A systemic review of adverse reactions has been established in Ja-pan (5) but not in South Korea (4) and Taiwan (6). During 1951–2004, a total of 39 cases of severe adverse vaccine reactions were reported in Japan, with an incidence rate of 0.182 cases of reac-tions/million vaccinations. Of the 39 cases, 27 patients (69.2%) had bone and joint involvement, and 13 (33.3%) had primary immunodeficiency (4). One patient had both complications. The BCG vaccine was initially produced in Taiwan using Pasteur-1173 P2 strain (0.025 mg/0.1mL) and changed to the less reactogenic Tokyo-172 strain (0.05 mg/0.1 mL) in 1979. From 1998 through 2007, 14 patients applied for compensation through the vaccine injury compensation program for BCG-caused adverse reaction, and 6 claims were confirmed. Of the 6 confirmed BCG complications cases, 5 patients had humeral or sternal os-teomyelitis and 1 patient died from a disseminated BCG infection. Accordingly , in 2002–2006 the risk for BCG osteitis/osteomyelitis and disseminated BCG infection was 3.68 and 0.9 per million, respectively (6). Incidence of severe complications was higher than that documented in Japan. Because Taiwan lacks diagnosis and postmarketing surveillance system , BCG-related complications might be underreported. As part of initiating a comprehensive adverse events surveillance, a laboratory program to differentiate M. …