Characteristics of poliovirus strains from long-term excretors with primary immunodeficiencies.

Individuals who are deficient in humoral immunity are particularly at risk from infection with enteroviruses, and poliovirus in particular, where antibodies are the main source of protection from disease. Long-term excretion of vaccine strains of poliovirus has been documented for many years and instances of paralytic poliomyelitis in hypogammaglobulinaemic patients who were subsequently found to have been excreting virus for prolonged periods have been reported in the U.S.A., Germany and Japan. The identification of a healthy immunodeficient patient in the U.K. who has probably been excreting type 2 poliovirus for 15 years will be described, with the characteristics of the virus and the results of attempts at treatment so far. Such individuals pose a significant risk to the eradication programme unless they can be identified and treated.