Do homeopathic nosodes protect against infection? An experimental test

Context For centuries, homeopathic practitioners have claimed that serially agitated dilutions of infectious agents (called "nosodes") are effective i n the prevention of infectious disease. However, no rigorous tests of this claim have been performed. Objective To test whether a nosode of Francisella tularensis-infected tissu e could protect from subsequent challenge with this pathogen in vivo. Design. Experimental laboratory test. Setting. A P3 containment laboratory at an infectious disease research faci lity Participants 142 male C3H/HeN specific, pathogen-free mice. Intervention Six levels of a nosode prepared from tularemia-infected tissue were produced All exposures were below the lowest level at which a classic al vaccination response was expected. The nosode and dilutent control solut ions were administered orally (.03 mL, 3 times per week)for 1 month before and after challenge. Animals were challenged with a potentially lethal nose (LD50 or LD75) Of F tularensis, then evaluated for time of death and total mortality. Main Outcome Measures Mortality and time to death. Results In a series of 15 trials (n=142), the tularemia nosode consistently produced increased mean times to death. All but 2 of 15 trials showed redu ced time to death in the nosode group and decreased mortality compared with controls. Protection rates averaged 22% over controls compared to 100% pro tection by standard vaccination. Conclusions This study found partial protection from a nosode of tularemia in dilutions below those expected to have protective effects, but not as gr eat as those produced by standard vaccination. If homeopathic nosodes can i nduce protection from infectious agents for which vaccination is currently unavailable, they may provide an interim method of reducing morbidity or mo rtality from such agents.