Hospital admission for suspected Yellow Fever is not always necessary for every mild fever, but you should be assessed urgently, and admission is recommended when symptoms are more severe or labs look abnormal—especially if there’s jaundice (yellow eyes/skin), bleeding, persistent vomiting, severe abdominal pain, dehydration, confusion, low blood pressure, reduced urine output, breathing trouble, or signs of liver/kidney injury, because severe disease can return after a brief “better” phase and needs close observation and supportive care; the CDC and WHO note that patients who develop more severe symptoms should be hospitalized for monitoring and treatment.