If the fever keeps recurring for several days, it means that the cause of the fever persists, but the body’s thermoregulatory center still plays a role in regulating the body temperature, so the fever keeps recurring. The recurrent fever is often caused by viral or bacterial infections, and the recurrent fever caused by Mycoplasma pneumoniae or Chlamydia infection is not excluded. If there is an increase in white blood cells, the fever is caused by a bacterial infection. If it is accompanied by a positive mycoplasma antibody, the organism is infected with Mycoplasma pneumoniae. If the C-reactive protein is elevated, or if it is accompanied by mild eosinophil elevation, it is possible that the fever is recurrent due to a viral infection, and antiviral drugs are more effective.