Passive immunity in newborns is provided through which mechanism?

• A. Vaccines given at birth
• B. The infant's own antibody production
• C. Antibodies transferred from mother through breast milk
• D. Antibiotics given at birth

Answer: (C)

Passive immunity happens when the baby receives already-made antibodies from another person, rather than making them itself. In newborns, maternal antibodies provide protection by being passed to the infant, first during pregnancy (IgG across the placenta) and then after birth through breast milk (primarily IgA on mucosal surfaces). This gives immediate, temporary protection while the infant’s own immune system matures. Vaccines would stimulate the infant’s own antibody production (active immunity), not provide a direct antibody supply. Antibiotics don’t confer immunity at all; they treat infections. So, antibodies from mother through breast milk are the mechanism that gives passive immunity to newborns.