Co-infection is defined by the infection of a host or cell by more than one pathogen (1, 2). Infections from the novel coronavirus severe acute respiratory syndrome coronavirus 2, SARS-CoV-2 (3), have resulted in the death of more than 200,000 Americans (4) and over 1,000,000 people worldwide (5) in less than one year. An upcoming influenza season raises the prospect of potential complications arising from co-infections involving SARS-CoV-2 (6). We mined published microarray data (7) to discover transcriptional features of viral co-infection in the blood of human patients. We identified the peptidylglycine alpha-amidating monooxygenase, PAM, as among the genes whose expression was most different in the blood of patients with a variety of viral co-infections, including co-infection of human coronavirus OC43 and influenza A. Transcriptional changes in PAM appeared to be specific to co-infection settings. PAM may be of relevance to fundamental transcriptional biology underlying viral co-infections of human blood.