%0 Journal Article %A Ignacio Martin-Loeches %A Antoni Torres %T Corticosteroids for CAP, influenza and COVID-19: when, how and benefits or harm? %D 2021 %R 10.1183/16000617.0346-2020 %J European Respiratory Review %P 200346 %V 30 %N 159 %X Purpose Corticosteroids have been considered in medicine for a long time, and they are broadly prescribed. In infectious diseases, corticosteroids have been regarded as a thread due to their immunosuppressive effects and therefore their anti-inflammatory properties.Main In recent years, there have been several studies published that aimed to determine the role of corticosteroids in patients with community-acquired pneumonia (CAP), because, despite significant advances in new antibiotics and supportive care, deaths of patients with CAP remain unacceptably high. While the 2007 Infectious Disease Society of America (IDSA)/American Thoracic Society (ATS) CAP guidelines did not mention the use of corticosteroids in the management of CAP, the recently published 2019 IDSA/ATS guidelines recommended their use in patients with septic shock refractory to vasopressors and fluid resuscitation. Regarding viral infection, the use of corticosteroids in patients with influenza has shown to be associated with significantly higher mortality and higher incidence of nosocomial infection, while in patients with coronavirus disease 2019 (COVID-19) there is a good body of evidence of the benefit of corticosteroids in terms of mortality.Conclusions The use of corticosteroids has been considered as a potential alternative co-adjuvant treatment in patients with pneumonia. In patients with COVID-19, the evidence is quite strong and there is a clear benefit of the use of corticosteroids in those patients presenting severe forms of disease.The recently published 2019 IDSA/ATS guidelines recommended the use of corticosteroids in the case of inpatients with septic shock refractory to vasopressors and fluid resuscitation https://bit.ly/39eXm30 %U https://err.ersjournals.com/content/errev/30/159/200346.full.pdf