Effect of MxA Guidance on Antiviral Treatment in Respiratory Viral Infections

The goal of this clinical trial is to evaluate the effects of myxovirus resistance protein A (MxA)-guided antiviral treatment on treatment duration and adverse outcomes in adults hospitalized with influenza or COVID-19, compared with usual care. Participants will be randomly assigned in a 1:1 ratio to the MxA group or the usual care group. In the MxA group, treating physicians will receive blood MxA test results together with treatment recommendations based on those results. In the usual care group, treating physicians will make antiviral treatment decisions without access to MxA results.