When does passive immunity from mom to baby end?

Passive immunity from mother to baby primarily lasts until the infant is around 6 months old, although some protection can extend up to 12 months. This immunity is mainly transferred through the placenta during pregnancy and through breast milk after birth. As the baby's immune system matures and begins to produce its own antibodies, the passive immunity gradually diminishes. Factors such as the mother's immunity and the baby's health can influence the exact duration.