H1N1 novel influenza A in pregnant and immunocompromised patients

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).

Review of the literature regarding influenza A in these patient groups, and review of published and unpublished data with regard to novel influenza A (H1N1).

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.

Optimal management of these patients is preventive by influenza vaccination, but the neuraminidase inhibitor antiviral agents provide effective treatment.