Which type of immunity is typically temporary and can occur via maternal antibodies passing to the fetus?

• A. Active immunity
• B. Natural immunity
• C. Adoptive immunity
• D. Passive immunity

Answer: (D)

Protection that comes from antibodies transferred from mother to child is passive immunity. Maternal IgG crosses the placenta, giving the fetus immediate defense against certain infections, and after birth, breast milk provides additional antibodies (notably secretory IgA) to protect the newborn’s mucosal surfaces. This immunity is temporary because the infant’s immune system isn’t producing these antibodies or memory cells; as maternal antibodies wear off, protection declines. In contrast, active immunity requires the individual to mount their own immune response and develop memory, which is longer-lasting. Adoptive immunity involves transferring immune components from another person, not the usual maternal antibody transfer.