Which type of immunity results from the transfer of antibodies between individuals?

Natural passive immunity occurs when antibodies are transferred from one individual to another without any involvement of the recipient's immune system actively generating those antibodies. This type of immunity typically occurs during pregnancy when maternal antibodies are transferred to the fetus through the placenta, and through breastfeeding, where infants receive antibodies in colostrum and breast milk. These antibodies provide the newborn with immediate protection against infections until the infant's own immune system is fully developed.

This form of immunity is transient, meaning it does not provide long-lasting protection since the antibodies will eventually degrade over time and are not replaced by the recipient's immune system. Understanding this process is essential for recognizing how infants are protected in early life while their immune systems mature. It's important to differentiate this process from other types of immunity, such as artificial passive, where antibodies are given through medical interventions like injections, or natural active and artificial active, which involve the immunity developing in response to infections or vaccinations.