H1N1 (2009) influenza A infection in transplant recipient patients: a comparative study versus non-transplanted patients

Objective

To compare H1N1 (2009) influenza A infection characteristics between transplant recipient patients and non-transplanted patients. To assess the evolution of transplanted patients up to 6 months following infection.

Methods

Patients diagnosed with confirmed influenza A infection from three Parisian transplant centers between September 1st, 2009 and February 15th, 2010. Clinical symptoms, biological, and radiological findings, and management were analysed and retrospectively compared between transplanted (T) and non-transplanted patients (NT). The evolution was assessed by a follow-up questionnaire, CT results 1 to 3 months after influenza infection and FEV1 variation.

Results

Seventy patients were included. Thirteen patients had an allograft (lung: eight, kidney: four, stem cells: one): (1) hospitalization: 100% (13 out of 13) in group T, 54% (31 out of 57) in group NT (P = 0.0013); (2) pneumonia: 62% (eight out of 13) in group T, 26% (eight out of 57) in group NT (P = 0.004); (3) mortality rate among hospitalized patients: 7.7% (one out of 13) in the group T, 9.7% (three out of 57) in group NT (P = NS); (4) chest CT scan abnormalities remained in four lung transplanted patients; (5) a minimum 10% decrease in FEV1 was detected in four lung transplant recipients.

Conclusion

Our results suggest that H1N1(2009) influenza A infection in transplant recipient patients compared to non-transplanted patients: (1) more often leads to hospitalization; (2) is more frequently associated with pneumonia; (3) is responsible for a persistent graft functional impairment in lung transplant recipients; (4) has a low mortality rate similar to admitted non-transplanted patients.