Development of vaccination strategies: from BCG to new vaccine candidates

During recent years, extensive development has been made to improving vaccines for tuberculosis. This is due to the presence of genome sequences of diverse mycobacterial species and Mycobacteroum tuberculosis (M. tuberculosis) isolates which has led to advances in the characterization of genes and antigens of M. tb and better realization of protective immune responses to the disease in both animals and humans. This review summarizes vaccine types, reasons for variable efficacy of BCG, latest advances in tuberculosis vaccine development and major vaccine design strategies.