Review article: Influenza A (H1N1) virus in patients with inflammatory bowel disease

Background: Infection with influenza A (H1N1)v (swine flu) has caused widespread anxiety, among patients who are potentially immunocompromised, such as those being treated for inflammatory bowel disease. Aim To provide guidance for physicians and their patients on the risk, prevention and management of influenza A (H1N1)v infection. Methods Medline was searched using the following key words: 'swine flu', 'immunosuppression', inflammatory bowel disease', 'recommendations', 'immunization', 'vaccination'. Organizations such as European Centre for Disease Prevention and Control, the Centers for Disease Control and Prevention and the World Health Organization were consulted for recent papers and recommendations regarding immunocompromised patients and influenza A (H1N1)v infection. Results Pandemic influenza A (H1N1) virus predominantly affects young patients. Those who are immunocompromised because of underlying disease or treatment are considered at higher risk of complications from influenza A (H1N1). They should be offered prevention (vaccination, postexposure prophylaxis) or treatment with antiviral drugs, if affected. Pneumococcal infection is a complication of influenza infection; therefore, pneumococcal vaccination appears advisable. Seasonal influenza vaccination is also recommended. Withdrawal of immunosuppressive treatment appears advisable during severe active infection if possible. Conclusions Pragmatic advice is the best that can be offered in the current circumstances because of paucity of evidence. Investigation into the impact of influenza A (H1N1)v infection in young people with chronic conditions is needed.