Response to tetanus immunization in onchocerciasis patients.

Fifty-five people were examined for tetanus antitoxin level two months after immunization with a single 0.5 ml dose of concentrated tetanus toxoid vaccine; only 7.1% of patients infected with onchocerciasis became immunized, whereas 44.5% were immunized in the control group. These results are consistent with previous observations of a reduced level of both cell-mediated and humoral immunity in patients heavily infected with parasitic diseases, especially onchocerciasis. This study raises doubts about the efficacy of immunization in young adult age groups and re-emphasizes the need for immunization in infancy.