The Complement Fixation Test after Prophylactic Typhoid Immunization and a Comparison with the Agglutination Test¹

In contrast with the strong agglutination test, a positive complement fixation test after prophylactic typhoid immunization is not as regular an occurrence, as it is during or after typhoid fever. This point may be of aid in deciding for or against the diagnosis of typhoid fever in an inoculated individual still having a positive Widal and ill with a suspicious typhoid but negative blood culture.

A positive complement fixation test was obtained most often after three injections with a polyvalent vaccine; two injections with this same vaccine or three injections with the single strain vaccine (Rawling) gave hardly any complement fixation.