Children less than what age do not mount an adequate immune response to t-cell independent immunity?

Children under the age of 2 years typically do not mount an adequate immune response to T-cell independent antigens. This is because their immune systems are still developing, particularly in their ability to generate T-cell responses that are crucial for responding to the more complex components of vaccines. T-cell independent immunity relies primarily on the activation of B-cells without the help of T-cells, which is less effective in infants and very young children.

This age group is at higher risk for infections that can be prevented by vaccines that require a robust T-cell response. The immune system becomes increasingly capable of responding to T-cell independent antigens as children grow, usually starting to see functional maturity around age 2, which makes this answer particularly notable. Consequently, vaccination strategies often take this age-related immune response variability into account when designing immunization schedules and the types of vaccines given to young children.