We investigated the risk and prognostic factors of pure viral sepsis in adult patients with community-acquired pneumonia (CAP), using the Sepsis-3 definition. Pure viral sepsis was found in 3% of all patients (138 of 4028) admitted to the emergency department with a diagnosis of CAP, 19% of those with CAP (138 of 722) admitted to the intensive care unit, and 61% of those (138 of 225) with a diagnosis of viral CAP. Our data indicate that males and patients aged ≥65 years are at increased risk of viral sepsis.