The Clinical and Virology effects of NA inhibitor in influenza virus infections (age;over 4 years old, under 13 years old): an open-label,randomized study Part 2

INTERVENTION: Oseltamivir Zanamivir Peramivir Laninamivir CONDITION: Childfood influenza infections PRIMARY OUTCOME: ‐Time to virus disappeared from the start of drug administration SECONDARY OUTCOME: ‐Time to return to normal body temperature (under 37.5 degrees); ‐Time of flu symptoms to disappear; ‐The amount of change per unit time of the virus titer to the last observation time and day 3; ‐The drug sensitivity change for each NA inhibitor; ‐The time course and antibody titer; ‐Rate of relapse INCLUSION CRITERIA: 1) Age:over 4 years old, under 13 years old. 2) Patients or Guardian of the patients with informd consent. 3) Out Patient of febrile symptom. 4) The patient who consulted within 48 hours of fever with over 37.5 degrees. 5) A rapid antigen test of Influenza is positive (type A).