A child's immune system typically begins to mature around 4 to 6 years of age.
While a child's immune system starts developing in the womb, it's not fully functional at birth. It continues to evolve and strengthen as the child is exposed to various pathogens and antigens in their environment. Key components of the immune system, such as memory T cells in the lungs and gut, require time to mature and develop the capacity for protective immunity. Research indicates that these cells become functionally mature and provide effective protection at around the ages of 4 to 6 years.
