The main symptoms of low immunity in babies are the following: First, babies are prone to recurrent infections, especially recurrent respiratory infections or intestinal infections. Second, each infection lasts longer than normal and is difficult to cure, and the condition is prone to recurrence. Third, immunocompromised babies have poor digestion, abnormal diet and varying degrees of malnutrition due to recurrent infections. Fourth, babies with low immunity will have symptoms of multiple systems and organs, symptoms of digestive system diseases, such as diarrhea and vomiting, and may also have symptoms of respiratory system diseases, such as cough and shortness of breath. There may also be symptoms of neurological disorders, such as convulsions, and symptoms of hematologic disorders, such as decreased granulocytes and anemia.