http://www.anthrax.mil/documents/library/Repeated.pdf
A group of intensively immunized men, who had been
subjected to detailed medical evaluations in 1956 and in
1962, was reexamined in 1971 and compared with a
carefully matched control group. Clinical and laboratory
studies were done to detect adverse effects induced by
repeated parenteral inoculation with a variety of vaccines
and toxoids. No clinical sequels attributable to long-term
immunization were identified. Only one laboratory abnormality
described in previous studies, elevated serum hexosamine,
was observed. Few other abnormalities were detected in the
immunized group; mean values were depressed for serum
albumin and serum iron levels and were elevated for serum
copper level and erythrocyte sedimentation rate. The
findings do not exclude possible development of adverse
consequences to individuals exposed to a similar course of
inoculations with higher dosages or with an equally intensive
course of injections with a single antigen or closely related
antigens.