Influenza virus infection in adult solid organ transplant recipients

Background: Solid organ transplant (SOT) recipients have been reported to be more susceptible to influenza virus. However, little is known about the clinical epidemiology and the implications of influenza viral infection among SOT recipients. Methods: Cohort study of influenza viral infection in SOT recipients at the University of Pittsburgh Medical Center. Results: Between November 1990 and April 2000, 30 cases of influenza were diagnosed in SOT recipients at our center, including influenza A (n = 22) and influenza B (n = 8). These included recipients of lung (n = 19), liver (n = 5) and kidney (n = 6) transplants. The incidence of influenza viral infection was 41.8 cases/1000 person years (PYs), 2.8 cases/1000 PYs and 4.3 cases/1000 PYs among lung, liver and renal transplant patients, respectively (p <0.0001). Symptoms were reported in all patients and included malaise, myalgia/arthralgia, fever, cough, and shortness of breath. Secondary bacterial pneumonia occurred in five patients (17%). Other complications were seen in three SOT recipients (2 liver and 1 kidney) and included: myocarditis, myositis, and bronchiolitis obliterans. Biopsy of the transplanted organ was performed in 21 SOT recipients (18 lung, 1 liver and 2 kidney) at the time of influenza viral infection. Overall, 62% (13/21) showed variable degrees of acute allograft rejection, and included 61% (11/18) of lung, and 100% (2/2) of kidney transplant recipients. Conclusions: Influenza infection is associated with significant morbidity in different groups of SOT recipients. Studies are needed to determine if yearly chemoprophylaxis with antiviral drugs might benefit this patient population.