GDF15 and infection: The elevated levels of serum GDF-15 in the acute phase of COVID-19 may predict the onset of long COVID in non-hospitalized patients. Mitochondria play a crucial role in maintaining individual homeostasis and dynamically altering metabolic and inflammatory responses throughout the body [10]. Therefore, levels of activated mitokines may provide a comprehensive assessment of the systemic status. Elevated serum GDF-15 levels are reportedly associated with undesirable aging and poor prognoses in chronic diseases and infections [15,16].