1. Reasons for poor immunity of babies There are many reasons for poor immunity of babies, mainly including the following aspects: 1. Genetic inheritance: Some babies are born with poor immunity, which is related to genetic inheritance. 2. Unbalanced diet: If the baby\’s diet is unbalanced and lacks nutrients, immunity will be affected. 3. Lack of exercise: Long-term lack of exercise will reduce body function and also affect immunity. 4. Environmental pollution: modern society