Invasive Aspergillosis Associated With Severe Influenza Infections

Background. Invasive aspergillosis may occur in the setting of severe influenza infections due to viral-induced respiratory epithelium disruption and impaired immune effects, but data are limited. Methods. A retrospective study was conducted among severe influenza cases requiring medical intensive care unit (ICU) admission at an academic center during the 2015–2016 season. Data collected included respiratory cultures, medical conditions and immunosuppressants, laboratory and radiographic data, and outcomes. A systematic literature review of published cases in the English language of aspergillosis complicating influenza was conducted. Results. Six (75%) of 8 ICU influenza cases had Aspergillus isolated; 5 were classified as invasive disease. No ICU patient testing negative for influenza infection developed aspergillosis during the study period. Among cases with invasive aspergillosis, influenza infection was type A (H1N1) (n = 2) and influenza B (n = 3). Published and current cases yielded n = 57 (European Organization for Research and Treatment of Cancer/Invasive Fungal Infections Cooperative Group and the National Institute of Allergy and Infectious Diseases Mycoses Study Group criteria: 37% proven, 25% probable, and 39% possible cases). An increasing number of cases were reported since 2010. Sixty-five percent of cases lacked classic underlying conditions at admission for aspergillosis, 86% had lymphopenia, and 46% died. Conclusions. Aspergillosis may occur in the setting of severe influenza infections even among immunocompetent hosts. Risks may include influenza A (H1N1) or B infections and viral-induced lymphopenia, although further studies are needed. Prompt diagnosis and antifungal therapy are recommended given high mortality rates.