Following inadvertent administration of OPV, exposure to a close contact given OPV, or exposure to wild-type poliovirus, immunocompromised patients can receive post-exposure prophylaxis with intramuscular human normal immunoglobulin (HNIG). A serum should be collected for baseline serology testing, but prophylaxis should not be delayed pending the results. HNIG is not indicated if the patient is known to be antibody-positive to all three poliovirus types. Stool samples are collected one week apart for analysis. If poliovirus is detected, administration of HNIG is repeated at 3-weekly intervals until two consecutive stool samples test negative. Intravenous immunoglobulin may be considered if intramuscular injections are contraindicated.