195 As the balance of evidence regarding the protective effect of Bacillus Calmette-Guerin (BCG) vaccination for tuberculosis disease/infection shifts between the positive and the negative in the past 100 years,1,2 BCG vaccination is still a major strategy of national tuberculosis control policy in most of countries following the recommendation of World Health Organization (WHO). In areas with a moderate tuberculosis burden, the national vaccination program usually includes BCG at birth to protect infants from meningitis and disseminated tuberculosis. The WHO reported a BCG coverage rate >80% for neonates and infants in countries where it was included in the national childhood immunization program.3 National BCG vaccination has been launched for use in infants in Taiwan since 1965. The coverage rate increased to 87% in 1975 and has remained above 97% since 2001.4,5 A number of BCG vaccine strains are available, with the French Pasteur strain 1173 P2, the Danish strain 1331, the Glaxo strain 1077 and the Tokyo strain 172 accounting for about 90% of BCG vaccinations worldwide.3 In terms of efficacy, no BCG strain is demonstrably better than another, and there is no global consensus as to which BCG strain is optimal for general use. The Pasteur strain was initially used when the BCG vaccination program was initiated in Taiwan back in the 1960s. The strain was then changed to the less reactogenic Tokyo 172 related strain due to the concern of axillary lymphadenitis in 1979.4 The protective effect of BCG in Taiwan can be demonstrated in three different ways. The Figure reveals the correlation between tuberculosis-related mortality in young children and the coverage rate of BCG vaccination in infancy. Before 1965, the mortality rate of extrapulmonary tuberculosis in children younger than 5 years was over 10/100,000 person-year. Meanwhile, the mortality rate of pulmonary tuberculosis in children at the same age was over 4/100,000 person-year. As the coverage rate scaled up sharply from zero to 70–80% during 1965–1970, the mortality rates halved, for both extrapulmonary and pulmonary tuberculosis in this age group. In the following 20 years, the mortality of extrapulmonary tuberculosis declined sharply, almost 100-fold from 10/100,000 in 1965 to 0.1/100,000 in 1985. The second aspect is to compare the incidence of childhood tuberculosis in Taiwan to those in other developed countries. For example, in USA, the incidence of adult tuberculosis was around 8–12/100,000 person-year during 1993–2001 and was 4–6/100,000 in children younger than 5 years.6 In Taiwan, the incidence of adult tuberculosis was 70/100,000 person-year, which was 10 times that in the USA. Tuberculosis incidence in children younger than 5 years in Taiwan was below Is Neonatal Bacillus Calmette-Guerin Vaccination Protective in Taiwan? Pei-Chun Chan,1* Li-Min Huang,2 Hsu-Sung Kuo1