Immunoglobulins (IGs), predominantly IgG antibodies, may be obtained from human or animal donors who have recovered from an infectious disease or who have been previously immunized.11 IGs provide immediate, short-term protection, i.e., passive immunity, for those who might develop infection before a vaccine could induce active immunity. Passive immunity is also useful when a vaccine is unavailable or contraindicated, or when an individual cannot produce antibodies.