title: H1N1 novel influenza A in pregnant and immunocompromised patients.
abstract: OBJECTIVE
  To describe the increased risk of severe disease and the appropriate management of patients at high risk such as pregnant women and immunosuppressed patients who acquire novel influenza A (H1N1).
  
  
  METHODS
  Review of the literature regarding influenza A in these patient groups, and review of published and unpublished data with regard to novel influenza A (H1N1).
  
  
  RESULTS
  Pregnant women are at increased risk for severe pneumonitis and respiratory failure from influenza infection, particularly during pandemics, including the current pandemic. Fetal morbidity is significant, usually resulting from maternal fever and severe hypoxemia. Early antiviral therapy using oseltamivir may be beneficial, and intensive care unit support should target adequate oxygenation at all times. Immunosuppressed patients are at increased risk for influenza, as well as at risk for more severe or prolonged infection. Patients after hematopoietic stem cell transplantation, after lung transplantation, and those receiving chemotherapy for leukemia are at highest risk, whereas the risk for human immunodeficiency virus-infected individuals appears relatively low. Treatment with antiviral therapy may be beneficial, even after the usual cut-off of 48 hrs after symptom onset.
  
  
  CONCLUSIONS
  Optimal management of these patients is preventive by influenza vaccination, but the neuraminidase inhibitor antiviral agents provide effective treatment.
authors.affiliation: Mount Sinai Hospital and the Interdepartmental Division of Critical Care, University of Toronto, Toronto, Ontario, Canada. stephen.lapinsky@utoronto.ca
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Lapinsky
mesh_terms: D000998:Antiviral Agents / Q000627:therapeutic use; D004196:Disease Outbreaks; D005260:Female; D005313:Fetal Death; D006801:Humans; D016867:Immunocompromised Host; D053118:Influenza A Virus, H1N1 Subtype; D007252:Influenza Vaccines; D007251:Influenza, Human / Q000188:drug therapy* / Q000453:epidemiology / Q000276:immunology; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000188:drug therapy* / Q000453:epidemiology / Q000276:immunology; D012131:Respiratory Insufficiency / Q000628:therapy; D018570:Risk Assessment; D012307:Risk Factors; D012720:Severity of Illness Index
chemical_list: D000998:Antiviral Agents; D007252:Influenza Vaccines