Safety and immunogenicity of a five-dose series of inactivated Mycobacterium vaccae vaccination for the prevention of HIV-associated tuberculosis.

Abstract

Five doses of inactivated Mycobacterium vaccae vaccine were administered intradermally to 22 human immunodeficiency virus (HIV)-infected patients (11 bacille Calmette-Guérin [BCG]-positive and 11 BCG-negative) in Zambia whose CD4 lymphocyte counts were >/=200 cells/mm(3). HIV viral load and lymphocyte proliferation responses were compared for vaccine recipients and 22 HIV-infected control patients (11 BCG-positive and 11 BCG-negative). Immunization was safe and well tolerated in all patients, and induration at the vaccine site decreased from dose 1 to dose 5. A transient decrease in HIV viral load was observed in BCG-positive vaccine recipients after dose 3 but not after subsequent doses. Median lymphocyte stimulation indices to M. vaccae were 6.0 in vaccine recipients and 2.3 in control patients (P<.001). Stimulation indices were >/=3.0 in 19 vaccine recipients (86%) and 7 control patients (32%; P=.001). A 5-dose series of vaccination with inactivated M. vaccae is safe in HIV-infected patients and induces lymphocyte proliferation responses to the vaccine antigen. M. vaccae vaccine is a candidate for the prevention of tuberculosis in HIV infection.