title: Longevity of protection by active immunization against necrotising enteritis in Papua New Guinea.
mesh_terms: D001428:Bacterial Vaccines / Q000627:therapeutic use*; D002648:Child; D003016:Clostridium perfringens / Q000276:immunology*; D004761:Enterocolitis, Pseudomembranous / Q000517:prevention & control*; D006801:Humans; D010219:Papua New Guinea; D013997:Time Factors; D014121:Toxoids / Q000627:therapeutic use*
chemical_list: D001428:Bacterial Vaccines; C035454:Clostridium perfringens toxoid; D014121:Toxoids