Q-fever soluble vaccine effects in Coxiella burneti sensitized humans.

A Q-fever soluble vaccine (phase I C. burnetitrichloro-acetic acid extract) was administered in a single dose to 28 persons formerly immunized with the same soluble vaccine one year before and to other 28 persons which had naturally been infected with C. burneti one or two years ago. All these persons were skin-tested with the same but diluted vaccine 48 hrs before vaccination. Mild local and general reactions were found only in the C. burneti previously infected vaccinees (local reactions in 9 cases and general reactions in 6 cases). Serological conversion was obtained in 92.8% (complement fixation test) and in 89.3% (mouse protection test) of the previously immunized individuals and in 96.4% (CF test) of the formerly Q-fever infected persons.