BCG vaccine bacilli that seemed less virulent, and changed the course of their research to see if repeated subculturing would produce a strain that was attenuated enough to be considered for use as a vaccine. The BCG strain was isolated after subculturing 239 times during 13 years from virulent strain on glycerine potato medium. The research continued throughout World War I until 1919, when the now avirulent bacilli were unable to cause tuberculosis disease in research animals. Calmette and Guerin transferred to the Paris Pasteur Institute in 1919. The BCG vaccine was first used in humans in 1921. Public acceptance was slow,
BCG disease outbreak in Finland in the 2000s to a different strain. In August 2002, the BCG vaccine used in Finland was discontinued by the manufacturer after factory inspectors were dissatisfied with the manufacturing process. Finland switched to a Danish strain BCG vaccine which did not have marketing authorization in Finland. Despite lack of marketing authorization, the vaccine was offered and recommended to all Finnish newborns (ca. 55 000 - 60 000 per year), and parents were not told the vaccine had no marketing authorization as required by Finnish and European Union legislation. The vaccine was injected into the thigh of newborns, despite clear manufacturer instructions that the