Efficacy and Safety of Valganciclovir vs. Oral Ganciclovir for Prevention of Cytomegalovirus Disease in Solid Organ Transplant Recipients

We compared the efficacy and safety of valganciclovir with those of oral ganciclovir in preventing cytomegalovirus (CMV) disease in high-risk seronegative solid organ transplant (SOT) recipients of organs from seropositive donors (D+/R-). In this randomised, prospective, double-blind, double-dummy study, 364 CMV D+/R- patients received valganciclovir 900 mg once daily or oral ganciclovir 1000 mg three times a day (tid) within 10 days of transplant and continued through 100 days. CMV disease, plasma viremia, acute graft rejection, graft loss and safety were analyzed up to 6 and 12 months post-transplant. Endpoint committee-defined CMV disease developed in 12.1% and 15.2% of valganciclovir and ganciclovir patients, respectively, by 6 months, though with a difference in the relative efficacy of valganciclovir and ganciclovir between organs (i.e. an organ type-treatment interaction). By 12 months, respective incidences were 17.2% and 18.4%, and the incidence of investigator-treated CMV disease events was comparable in the valganciclovir (30.5%) and ganciclovir (28.0%) arms. CMV viremia during prophylaxis was significantly lower with valganciclovir (2.9% vs. 10.4%; p=0.001), but was comparable by 12 months (48.5% valganciclovir vs 48.8% ganciclovir). Time-to-onset of CMV disease and to viremia were delayed with valganciclovir; rates of acute allograft rejection were generally lower with valganciclovir. Except for a higher incidence of neutropenia with valganciclovir (8.2%, vs 3.2% ganciclovir) the safety profile was similar for both drugs. Overall, once-daily oral valganciclovir was as clinically effective and well-tolerated as oral ganciclovir tid for CMV prevention in high-risk SOT recipients.     

Cytomegalovirus Disease in High-Risk Transplant Recipients Despite Ganciclovir or Valganciclovir Prophylaxis

The clinical patterns and predictors of cytomegalovirus (CMV) disease in kidney and/or pancreas transplant patients on ganciclovir (1.0 g po t.i.d.) or valganciclovir (450 mg po q.d.) prophylaxis were studied. This is a retrospective analysis of 129 transplant recipients. Median follow up was 12 months (range, 6-18 months). The overall incidence of CMV disease at 1-year post-transplant was 14% (4% tissue-invasive, 10% noninvasive). Seventeen of 18 patients were diagnosed with CMV after completion of 3 months' prophylaxis (median 8 weeks, range, 2-28 weeks). Induction treatment with thymoglobulin, and Donor +/Recipient - CMV status were the strongest predictors for the development of CMV disease. Cytomegalovirus incidence was not different between patients treated with ganciclovir or valganciclovir (15 vs. 17%, respectively). Valganciclovir (450 mg q.d.) is as effective as oral ganciclovir in CMV prophylaxis. High-risk individuals might require higher doses or longer duration of valganciclovir treatment.     

Oral Valganciclovir Is Noninferior to Intravenous Ganciclovir for the Treatment of Cytomegalovirus Disease in Solid Organ Transplant Recipients

Intravenous ganciclovir is the standard treatment for cytomegalovirus disease in solid organ transplant recipients. Oral valganciclovir is a more convenient alternative. In a randomized, international trial, recipients with cytomegalovirus disease were treated with either 900 mg oral valganciclovir or 5 mg/kg i.v. ganciclovir twice daily for 21 days, followed by 900 mg daily valganciclovir for 28 days. A total of 321 patients were evaluated (valganciclovir [n = 164]; i.v. ganciclovir [n = 157]). The success rate of viremia eradication at Day 21 was 45.1% for valganciclovir and 48.4% for ganciclovir (95% CI -14.0% to +8.0%), and at Day 49; 67.1% and 70.1%, respectively (p = NS). Treatment success, as assessed by investigators, was 77.4% versus 80.3% at Day 21 and 85.4% versus 84.1% at Day 49 (p = NS). Baseline viral loads were not different between groups and decreased exponentially with similar half-lives and median time to eradication (21 vs. 19 days, p = 0.076). Side-effects and discontinuations of assigned treatment (18 of 321 patients) were comparable. Oral valganciclovir shows comparable safety and is not inferior to i.v. ganciclovir for treatment of cytomegalovirus disease in organ transplant recipients and provides a simpler treatment strategy, but care should be taken in extrapolating to organ transplant recipients not properly represented in the present study.     

Clinical Utility of Cytomegalovirus Viral Load Testing for Predicting CMV Disease in D+/R- Solid Organ Transplant Recipients

Despite prophylaxis, cytomegalovirus (CMV) disease is common in donor seropositive (D+)/recipient seronegative (R-) transplant patients after cessation of prophylaxis. Early detection of CMV may allow for pre-emptive therapy to prevent active disease. The clinical utility of quantitative plasma viral load measurements for predicting CMV disease was determined in 364 D+/R- organ transplant patients receiving prophylaxis (100 d of valganciclovir or oral ganciclovir). Measurements were performed every 2 weeks until day 100 and at months 4, 4.5, 5, 6, 8 and 12 post-transplant. CMV disease occurred in 64 (17.6%) patients by 12 months. Using a positive cut-off value of >400 copies/mL, sensitivity was 38%, specificity 60%, positive predictive value 17%, and negative predictive value 82% for prediction of CMV disease. Therefore, routine monitoring would have predicted disease in only 24/64 (38%) patients. The test characteristics were not improved by changing the viral load cut-off point for defining a positive result. Similarly, single time point measures at the end of prophylaxis or month 4 had low sensitivity for disease prediction. Overall, regular CMV plasma viral load measurements were only of modest value in predicting CMV disease.     

Primary CMV Infections Are Common in Kidney Transplant Recipients After 6 Months Valganciclovir Prophylaxis

Prolonging cytomegalovirus (CMV) prophylaxis in CMV seronegative recipients of a kidney from CMV seropositive donor (D+/R–) may reduce the incidence of late infections. We analyzed late‐onset primary CMV infections after 6 months valganciclovir prophylaxis. Data from all CMV D+/R– kidney transplant recipients between January 2004 and December 2008 at our center were analyzed. Patients with a functioning graft at 6 months after transplantation who received 6 months of valganciclovir prophylaxis 900 mg once daily were included (N = 127). CMV was diagnosed with quantitative PCR. Prophylaxis was completed in 119 patients. Prophylaxis was stopped at 3–5 months due to leukopenia or gastrointestinal side effects in eight patients. Late‐onset primary CMV infection developed in 47/127 (37%) patients median 244 days after transplantation (range 150–655) and median 67 days after the cessation of prophylaxis (range 1–475). Four infections were asymptomatic. In others, symptoms included fever (N = 28), gastrointestinal symptoms (nausea, vomiting, diarrhea) (N = 24), respiratory tract symptoms (N = 12), and hepatopathy (N = 6). Median peak viral load was 13500 copies/mL (range 400–2 831 000). Recurrent CMV infection developed in 9/47 (19%) patients. No significant risk factors for CMV infection were identified. Symptomatic primary CMV infections were commonly detected also after prolonged valganciclovir prophylaxis.     

A Multicenter Study of Valganciclovir Prophylaxis up to Day 120 in CMV-Seropositive Lung Transplant Recipients

Seventy-six cytomegalovirus (CMV)-seropositive lung transplant recipients receiving valganciclovir (900 mg/day) for CMV prophylaxis were compared with a group of 87 patients receiving oral ganciclovir (3000 mg/day). Prophylaxis was administered to day 120 post-transplantation and follow-up was 1 year. In addition, a study was conducted on risk factors for CMV infection/disease. CMV disease incidence was 7.9% and 16.1% for valganciclovir and oral ganciclovir, respectively (p = 0.11). Patients receiving valganciclovir had fewer viral syndromes (2.6% vs. 11.5%, p < 0.05), a similar rate of tissue-invasive disease (5.2% vs. 4.6%, p = ns), longer time-to-onset of CMV infection/disease (197.5 vs. 155.2 days, p < 0.05), and a lower probability of infection/disease while on prophylaxis (1.3% vs. 12.6%, p < 0.01). Nonetheless, leukopenia incidence was higher with valganciclovir (15.8% vs. 2.3%, p < 0.01), as was the need for treatment withdrawal due to adverse effects (11.8% vs. 1.1%, p < 0.01). CMV infection was similar in both groups (32.9% vs. 34.5%). Induction therapy with basiliximab and glucocorticosteroid treatment were independent risk factors for developing CMV infection/disease. In conclusion, valganciclovir prophylaxis results in a low incidence of CMV disease in lung transplant recipients and appears more effective than oral ganciclovir. Despite the comparatively higher incidence of adverse events with valganciclovir, the drug can be considered safe for prophylaxis.     

Long-Term Outcomes of CMV Disease Treatment with Valganciclovir Versus IV Ganciclovir in Solid Organ Transplant Recipients

Though an important cause of morbidity and mortality in solid organ transplantation (SOT), the long-term outcomes of cytomegalovirus (CMV) disease treatment have not been well studied. In a randomized trial, 321 SOT recipients with CMV disease were followed 1 year after treatment with either twice daily intravenous ganciclovir or oral valganciclovir (for 21 days) followed by once daily valganciclovir until day 49 in all patients. Clinical and viral eradication of CMV disease was similar between groups. Clinical recurrence beyond day 49 was found in 15.1% and virological recurrence in 30.0%, no difference between groups (p > 0.77). In a multivariable logistic regression analysis, the only independent predictor for recurrence was failure to eradicate DNAemia by day 21 (clinical: OR 3.9 [1.3–11.3], p = 0.012; virological: OR 5.6 [2.5–12.6], p < 0.0001). Eight patients developed ganciclovir resistance, with no difference between groups (p = 0.62). Twenty patients (valganciclovir: 11, ganciclovir: 9, p = 0.82) died, 12 due to infections, two involving CMV disease. There were no differences in long-term outcomes between treatment arms, further supporting the use of oral valganciclovir for treatment of CMV disease. Persistent DNAemia at day 21, CMV IgG serostatus and development of resistance may be relevant factors for further individualization of treatment.     

A Trial of Valganciclovir Prophylaxis for Cytomegalovirus Prevention in Lung Transplant Recipients

Cytomegalovirus (CMV) infection is common after lung transplantation. We performed a prospective trial of valganciclovir prophylaxis in lung recipients with outcomes compared to matched historical controls. The valganciclovir group (n = 40) (including D+/R- and R+ patients) was prospectively enrolled, and received oral valganciclovir 900 mg once daily for 12 weeks. Historical controls (n = 40) received 12 weeks of daily intravenous ganciclovir if D+/R- or 12 weeks of oral ganciclovir if R+. CMV viral load testing was done at two-week intervals until 6 months posttransplant. Baseline demographics and immunosuppression were comparable in the two groups. The incidence of CMV viremia was 16/40 (40.0%) in the valganciclovir arm versus 18/40 (45%) in the ganciclovir arm (p = NS). The incidence of symptomatic CMV disease was 8/40 (20%) versus 7/40 (17.5%), respectively (p = NS). In both groups viremia, while on prophylaxis, was uncommon (valganciclovir: 0/40 and ganciclovir: 2/40). Peak viral load and time to viremia were similar in the two arms. High rates of viremia and symptomatic disease occurred in the D+/R- patients after discontinuation of prophylaxis. Genotypic CMV sequence analysis demonstrated low rates of ganciclovir resistance in both groups. Valganciclovir prophylaxis had similar efficacy to either intravenous ganciclovir (D+/R- patients), or oral ganciclovir (R+ patients) in lung recipients.     

Polyfunctional Cytomegalovirus‐Specific Immunity in Lung Transplant Recipients Receiving Valganciclovir Prophylaxis

Cytomegalovirus (CMV) is a common opportunistic infection after lung transplant. Despite effective antiviral medications to treat CMV, invasive CMV disease contributes to lung allograft dysfunction and worse survival. Efforts to prevent CMV have led to the use of valganciclovir prophylaxis for increasingly longer periods after transplant. A pivotal concern with long‐term antiviral prophylaxis is that it may prevent or delay the development of CMV‐specific immunity and increase the subsequent risk of late onset disease. To address this issue, we conducted a pilot study to determine if CMV‐specific immunity was detectable in lung transplant recipients at risk for CMV while on antiviral prophylaxis. Utilizing polychromatic flow cytometry panels, CMV‐specific immunity was determined by peripheral blood CD4 and CD8 T cell expression of cytokines in response to the HLA restricted CMV peptides pp65 and IE‐1. We determined CMV seropositive lung transplant recipients on valganciclovir for a median of 6 months from transplant have a detectable polyfunctional CMV‐specific T cell response which is comparable to seropositive recipients not on antiviral medications and to healthy seropositive nontransplant controls. Thus, valganciclovir prophylaxis does not appear to impair the development of CMV‐specific immunity in lung transplantation.     

Pharmacokinetics of Low and Maintenance Dose Valganciclovir in Kidney Transplant Recipients

Valganciclovir is commonly used for cytomegalovirus (CMV) prophylaxis in renal transplant patients. A fixed dose of 900 mg daily is typically recommended, however, there has never been a formal pharmacokinetic study comparing various doses in renal transplant patients. We therefore compared the pharmacokinetic characteristics of intravenous ganciclovir (IV GCV) and oral ganciclovir (GCV) with two different doses of valganciclovir (VGCV) in an open-label crossover study. Ten adult kidney recipients participated in a four-phase crossover treatment schedule of IV GCV (2.5 mg/kg every 12 h), VGCV (900 mg daily), VGCV (450 mg daily) and oral GCV (1000 mg Q8 H). IV GCV and oral VGCV 900 mg daily achieved similar values for AUC_0–24 (median 60.63 vs. 62.86 μg/h/mL). Oral VGCV 450 mg achieved comparable AUC_0–24 values as oral GCV 1000 mg Q8 H (median AUC_0–24 35.9 vs. 29.04 μg/h/mL). Oral VGCV 900 mg daily provided systemic GCV exposure similar to IV GCV and confirms PV 16 000 study results. Further, VGCV 450 mg daily provided comparable systemic exposure versus oral GCV. Due to its favorable pharmacokinetic profile, data herein suggest that VGCV can be used in the early post-kidney transplant period, and that 450 mg daily provides ample drug exposure for effective CMV prophylaxis in kidney transplant patients.     

Clinical Utility of Cytomegalovirus (CMV) Serology Testing in High-risk CMV D+/R− Transplant Recipients

Late-onset cytomegalovirus (CMV) disease is a significant problem in D+/R- solid organ transplant (SOT) patients who receive antiviral prophylaxis. We assessed the clinical utility of CMV IgG and IgM serology testing for predicting late-onset CMV disease. We evaluated 352 D+/R- transplant recipients who participated in a trial comparing 100 days of ganciclovir versus valganciclovir prophylaxis. CMV serology was assessed on day 28, 56, 100, and 6 and 12 months post-transplant. IgG seroconversion occurred in 26.9% of patients by day 100, and in 63.4% and 75.3% by 6 and 12 months, respectively. IgM seroconversion occurred in 8.3%, 41.8% and 54.9% by day 100, month 6 and month 12, respectively. Seroconversion by day 100 (end of prophylaxis) was not predictive of subsequent CMV disease (CMV disease 13.3% if seropositive vs. 17.8% if seronegative; p = NS). However, at 6 months post-transplant, IgG serostatus was predictive of subsequent CMV disease between month 6 and 12 (CMV disease 1.3% if seropositive vs. 10.0% if seronegative; p = 0.002). In D+/R- patients, CMV serology testing is for the most part not clinically useful for predicting subsequent disease. However, seroconversion by 6 months may be useful for identifying patients at risk of late-onset CMV disease.     

Prophylactic Versus Preemptive Oral Valganciclovir for the Management of Cytomegalovirus Infection in Adult Renal Transplant Recipients

Prophylaxis reduces cytomegalovirus (CMV) disease, but is associated with increased costs and risks for side effects, viral resistance and late onset CMV disease. Preemptive therapy avoids drug costs but requires frequent monitoring and may not prevent complications of asymptomatic CMV replication. Kidney transplant recipients at risk for CMV (D+/R-, D+/R+, D-/R+) were randomized to prophylaxis (valganciclovir 900 mg q.d. for 100 days, n=49) or preemptive therapy (900 mg b.i.d. for 21 days, n=49) for CMV DNAemia (CMV DNA level>2000 copies/mL in >or=1 whole blood specimens by quantitative PCR) assessed weekly for 16 weeks and at 5, 6, 9 and 12 months. More patients in the preemptive group, 29 (59%) than in the prophylaxis group, 14 (29%) developed CMV DNAemia, p=0.004. Late onset of CMV DNAemia (>100 days after transplant) occurred in 11 (24%) randomized to prophylaxis, and none randomized to preemptive therapy. Symptomatic infection occurred in five patients, four (3 D+/R- and 1 D+/R+) in the prophylactic group and one (D+/R-) in the preemptive group. Peak CMV levels were highest in the D+/R- patients. Both strategies were effective in preventing symptomatic CMV. Overall costs were similar and insensitive to wide fluctuations in costs of either monitoring or drug.     

Zygomycosis in Solid Organ Transplant Recipients in a Tertiary Transplant Center and Review of the Literature

Zygomycetes are ubiquitous fungi that can cause invasive disease associated with high mortality. We report 10 solid organ transplant recipients with zygomycosis (incidence 2 per 1000) and reviewed 106 cases in the English-language literature. These included renal (n = 73), heart (n = 16), lung (n = 4), heart/lung (n = 2), liver (n = 19) and kidney/pancreas (n = 2) transplant recipients. All patients were receiving immunosuppression and the vast majority steroids. The clinical presentation included rhino-sino-orbital (n = 20), rhinocerebral (n = 16), pulmonary (n = 28), gastrointestinal (n = 13), cutaneous (n = 18), renal (n = 6) and disseminated disease (n = 15). Most frequently isolated genera were Rhizopus (73%) followed by Mucor (13%). The overall mortality was 49%. While rhino-sino-orbital disease had the best prognosis, rhinocerebral disease had high mortality (93%) comparable to disseminated disease. A favorable outcome was associated with limited, surgically accessible disease and early surgical intervention along with amphotericin B administration.     

Incidence Rate and Outcome of Gram-Negative Bloodstream Infection in Solid Organ Transplant Recipients

Bacterial infections are common complications of solid organ transplantation (SOT). In this study, we defined the incidence, mortality and in vitro antimicrobial resistance rates of Gram-negative bloodstream infection (BSI) in SOT recipients. We identified 223 patients who developed Gram-negative BSI among a cohort of 3367 SOT recipients who were prospectively followed at the Mayo Clinic (Rochester, MN) from January 1, 1996 to December 31, 2007. The highest incidence rate (IR) of Gram-negative BSI was observed within the first month following SOT (210.3/1000 person-years [95% confidence interval (CI): 159.3–268.3]), with a sharp decline to 25.7 (95% CI: 20.1–32.1) and 8.2 (95% CI: 6.7–10.0) per 1000 person-years between 2 and 12 months and more than 12 months following SOT, respectively. Kidney recipients were more likely to develop Gram-negative BSI after 12 months following transplantation than were liver recipients (10.3 [95% CI: 7.9–13.1] vs. 5.2 [95% CI: 3.1–7.8] per 1000 person-years). The overall unadjusted 28-day all-cause mortality of Gram-negative BSI was 4.9% and was lower in kidney than in liver recipients (1.6% vs. 13.2%, p < 0.001). We observed a linear trend of increasing resistance among Escherichia coli isolates to fluoroquinolone antibiotics from 0% to 44% (p = 0.002) throughout the study period. This increase in antimicrobial resistance may influence the choice of empiric therapy.     

Valacyclovir Prophylaxis Versus Preemptive Valganciclovir Therapy to Prevent Cytomegalovirus Disease After Renal Transplantation

Both preemptive therapy and universal prophylaxis are used to prevent cytomegalovirus (CMV) disease after transplantation. Randomized trials comparing both strategies are sparse. Renal transplant recipients at risk for CMV (D+/R−, D+/R+, D−/R+) were randomized to 3-month prophylaxis with valacyclovir (2 g q.i.d., n = 34) or preemptive therapy with valganciclovir (900 mg b.i.d. for a minimum of 14 days, n = 36) for significant CMV DNAemia (≥2000 copies/mL by quantitative PCR in whole blood) assessed weekly for 16 weeks and at 5, 6, 9 and 12 months. The 12-month incidence of CMV DNAemia was higher in the preemptive group (92% vs. 59%, p < 0.001) while the incidence of CMV disease was not different (6% vs. 9%, p = 0.567). The onset of CMV DNAemia was delayed in the valacyclovir group (37 ± 22 vs. 187 ± 110 days, p < 0.001). Significantly higher rate of biopsy-proven acute rejection during 12 months was observed in the preemptive group (36% vs. 15%, p = 0.034). The average CMV-associated costs per patient were $5525 and $2629 in preemptive therapy and valacyclovir, respectively (p < 0.001). However, assuming the cost of $60 per PCR test, there was no difference in overall costs. In conclusion, preemptive valganciclovir therapy and valacyclovir prophylaxis are equally effective in the prevention of CMV disease after renal transplantation.     

Effects of the Intensity of Immunosuppressive Therapy on Outcome of Treatment for CMV Disease in Organ Transplant Recipients

An effective host immune response, critical for successful control of Cytomegalovirus (CMV) disease in solid organ transplant recipients, is affected by intensity and type of immunosuppressive therapy. We used information prospectively captured in the VICTOR‐trial to investigate the impact of immunosuppressive therapy on short‐ and long‐term outcomes of CMV treatment in organ transplant recipients. Dual, as compared to triple, immunosuppressive therapy ([odds ratios] OR of 2.55; 95% CI: 1.51–4.60; p = 0.002), lower blood concentrations of calcineurin inhibitors (OR of 5.53; CI: 1.04–29.35; p = 0.045), and longer time since transplantation (OR of 1.70; CI: 1.01–2.87; p = 0.047) all showed better early (Day 21) CMV DNAemia eradication. We observed no effect of the intensity of the immunosuppressive therapy on overall rates of viral eradication or recurrence. The type of calcineurin inhibitor (tacrolimus/cyclosporine) or use of mycophenolate did not affect treatment efficacy, although both tacrolimus and mycophenolate treated patients showed a lower rate of virological recurrence OR 0.51 (95% CI: 0.26–0.98; p = 0.044) and OR 0.45 (95% CI: 0.22–0.93; p = 0.031), respectively. Lower total intensity of immunosuppressive therapy was associated with more effective early, but not overall, CMV DNAemia eradication by valganciclovir/ganciclovir therapy. Both mycophenolate and tacrolimus (rather than cyclosporine) therapy seem to be associated with reduced risk of recurrence.     

Outcomes of Pediatric Kidney Transplantation in Recipients of a Previous Non‐Renal Solid Organ Transplant

Children who receive a non‐renal solid organ transplant may develop secondary renal failure requiring kidney transplantation. We investigated outcomes of 165 pediatric kidney transplant recipients who previously received a heart, lung, or liver transplant using data from 1988 to 2012 reported to the United Network for Organ Sharing. Patient and allograft survival were compared with 330 matched primary kidney transplant (PKT) recipients. Kidney transplantation after solid organ transplant (KASOT) recipients experienced similar allograft survival: 5‐ and 10‐year graft survival was 78% and 60% in KASOT recipients, compared to 80% and 61% in PKT recipients (p = 0.69). However, KASOT recipients demonstrated worse 10‐year patient survival (75% KASOT vs. 97% PKT, p < 0.001). Competing risks analysis indicated that KASOT recipients more often experienced graft loss due to patient death (p < 0.001), whereas allograft failure per se was more common in PKT recipients (p = 0.01). To study more recent outcomes, kidney transplants performed from 2006 to 2012 were separately investigated. Since 2006, KASOT and PKT recipients had similar 5‐year graft survival (82% KASOT vs. 83% PKT, p = 0.48), although 5‐year patient survival of KASOT recipients remained inferior (90% KASOT vs. 98% PKT, p < 0.001). We conclude that despite decreased patient survival, kidney allograft outcomes in pediatric KASOT recipients are comparable to those of PKT recipients.     

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/1,000 person years (PYs), 2.8 cases/1000 PYs and 4.3 cases/ 1,000 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.