How do b-cell deficiencies people benefit from artificial passive immunotherapy?

IVIG. Intravenous immunoglobulins (ivig) is passive therapy whereby an infusion provides the necessary immune proteins to fight infection if there is a b cell deficiency or a deficiency in b cell derived immune proteins. Ivig infusions contain immunoglobulins that provide temporary immunity. The infusions have to be repeated every 4 weeks or so. They can even be given subcutaneously in the home.
Definitions. B cell deficiencies are characterized by absent or deficient production of specific antibodies to substances, for example vaccines. For these patients to be protected from infections, a pool of antibodies from healthy donors (ivig) is given. Passive immunotherapy means giving antibodies, the can be ivig or specific antibodies against a microbe, for example anti-tetanus antibodies.