Protection against fatal Klebsiella pneumoniae sepsis in the squirrel monkey Saimiri sciureus after immunization with a capsular polysaccharide vaccine.

An anti-Klebsiella pneumoniae K5a capsular polysaccharide vaccine was evaluated as a preventive approach for protecting squirrel monkeys, Saimiri sciureus, in our breeding colony. Based on an 8-month vaccination schedule over a period of more than two years, this vaccine, regardless of the animal's age, resulted in a reduction of this particular bacterial infection and its generally associated fatal outcome. IgG antibody responses in naive and vaccinated animals were monitored over an extended period by radioimmunoassay and showed a marked increase above the initial naturally occurring antibody titres. No side-effects were observed after repeated vaccination of several hundred animals during a two-year period.