In the outpatient clinic, we often meet parents who bring their children to the clinic after going to many hospitals, and they say, “Doctor, my child’s immune function is particularly poor, and he or she has recurrent colds and needs repeated infusions. I would like to have my child’s immune function checked”. Is a child’s poor immune function the cause of frequent “colds” (upper respiratory tract infections) or recurrent “bronchitis” and “pneumonia” (lower respiratory tract infections)? Do I need to do immune function tests on these children? When I encounter such patients, I always observe the general condition of the child’s growth and development, and ask the parents a series of questions before issuing tests and other treatment. A: At least once or twice a month, or even several times a month without getting well. Q: What are the main symptoms of each cold? A: Each time is a fever, a temperature of more than 37 degrees, or a runny nose, or sneezing. Q: How were all these symptoms treated? A: Every time, I get an IV (intravenous infusion) for many days, or even for more than half a month. Q: Why do I always need IV fluids? A: I can’t get well without an IV, and I’m afraid that the high temperature will burn my child up. Q: Do you often use dexamethasone and other hormone preparations for each infusion? A: Yes, almost every time, the child’s temperature is not well controlled without it. The root cause of the child’s recurrent upper respiratory tract infections was not his own innate immune function, but over-treatment! It was the parents’ excessive nervousness that forced the local doctor to over-treat the child. Is this conclusion too “arbitrary”? What is the reasoning behind it? In the face of parents’ confusion, I would use this analogy: Under normal circumstances, the human body raises many immune cells, and the human body relies on these immune cells to play the ability to fight infection, which is like a country raising many soldiers, and the country relies on the combat ability of these soldiers to defend against foreign invasion. If you don’t train your soldiers, their combat ability will decrease; whenever you have a cold or fever, it is an opportunity for your body to give these immune cells a chance to train and practice, and after the training, the immune cells’ ability to fight infection will be enhanced. However, if a child has a fever, we immediately give him/her intravenous fluids and apply hormones (glucocorticoids) to forcefully control his/her body temperature, which is equivalent to depriving the soldiers (immune cells of the body) of this opportunity to practice. In the long run, the immune cells will become inert because they are always deprived of exercise, resulting in a decrease in their ability to fight infection. Moreover, repeated application of glucocorticoids itself can lead to secondary immune function decline. In addition, excessive and inappropriate application of antibiotics also disrupts the normal flora of the body and weakens the immune function of the body. Therefore, excessive treatment can do no good, and we should not give inappropriate treatment to children just to relieve parents’ nervousness. As for the runny nose and sneezing that last for many days, they are often not symptoms of upper respiratory tract infection, but the manifestation of the body’s allergic reaction (respiratory tract allergy). The problem of the body’s allergic reaction is not solved by intravenous antibiotic infusion. In addition, recurrent bronchitis or pneumonia and other lower respiratory tract infections in children are often the result of chronic cough or bronchial asthma due to airway hyperresponsiveness, and the underlying cause is not the child’s innate immune deficiency. Therefore, it is “arbitrary” to say that the crux of these problems that parents are struggling with is not in the immune function, and there is no need for immune function screening. Of course, congenital immune deficiency has its own characteristic manifestations and screening measures, which need to be grasped and handled by a specialist. Having found the crux of the problem, what should be done next? First, parents’ awareness and behavior should be raised to eliminate the vicious circle of overstress and overtreatment. Secondly, when a child shows signs of infection, he or she should go to a regular hospital and receive standardized treatment. In case of fever, the first thing you should do is to check the infection indicators at the local hospital, such as blood count and C-reactive protein, etc. If the infection indicators are not high, stop the infusion. Finally, change your child’s living habits, eat a balanced diet, work and rest regularly, do more outdoor activities, and older children should participate in physical exercise to enhance their physical fitness.