Reduced incidence of pneumonia in influenza-vaccinated solid organ transplant recipients with influenza disease

Respiratory viral infections including COVID-19 in solid organ transplantation

PURPOSE OF REVIEW

Respiratory viral infections are prevalent and contribute to significant morbidity and mortality among solid organ transplant (SOT) recipients. We review updates from literature on respiratory viruses, including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), in the SOT recipient.

RECENT FINDINGS

With the wider availability and use of molecular diagnostic tests, our understanding of the epidemiology and impact of respiratory viruses in the SOT population continues to expand. While considerable attention has been given to the coronavirus disease 2019 (COVID-19) pandemic, the advances in prevention and treatment strategies of SARS-CoV-2 offered valuable insights into the development of new therapeutic options for managing other respiratory viruses in both the general and SOT population.

SUMMARY

Respiratory viruses can present with a diverse range of symptoms in SOT recipients, with potentially associated acute rejection and chronic lung allograft dysfunction in lung transplant recipients. The epidemiology, clinical presentations, diagnostic approaches, and treatment and preventive strategies for clinically significant RNA and DNA respiratory viruses in SOT recipients are reviewed. This review also covers novel antivirals, immunologic therapies, and vaccines in development for various community-acquired respiratory viruses.

Transcriptome signatures preceding the induction of anti-stalk antibodies elicited after universal influenza vaccination

A phase 1 clinical trial to test the immunogenicity of a chimeric group 1 HA (cHA) universal influenza virus vaccine targeting the conserved stalk domain of the hemagglutinin of influenza viruses was carried out. Vaccination with adjuvanted-inactivated vaccines induced high anti-stalk antibody titers. We sought to identify gene expression signatures that correlate with such induction. Messenger-RNA sequencing in whole blood was performed on the peripheral blood of 53 vaccinees. We generated longitudinal data on the peripheral blood of 53 volunteers, at early (days 3 and 7) and late (28 days) time points after priming and boosting with cHAs. Differentially expressed gene analysis showed no differences between placebo and live-attenuated vaccine groups. However, an upregulation of genes involved in innate immune responses and type I interferon signaling was found at day 3 after vaccination with inactivated adjuvanted formulations. Cell type deconvolution analysis revealed a significant enrichment for monocyte markers and different subsets of dendritic cells as mediators for optimal B cell responses and significant increase of anti-stalk antibodies in sera. A significant upregulation of immunoglobulin-related genes was only observed after administration of adjuvanted vaccines (either as primer or booster) with specific induction of anti-stalk IGVH1-69. This approach informed of specific immune signatures that correlate with robust anti-stalk antibody responses, while also helping to understand the regulation of gene expression induced by cHA proteins under different vaccine regimens.

Influenza vaccination in immunocompromised populations: Strategies to improve immunogenicity

Immunocompromised individuals are at high risk of severe illness and complications from influenza infection. For this reason, immunization using inactivated influenza vaccines is recommended for transplant patients, individuals receiving immunosuppressant treatments, and other persons with immunodeficiency. However, these immunocompromised populations are more likely to have lower and non-protective responses to annual vaccination with a standard influenza vaccine. Here, we review strategies aimed to improve the immunogenicity of influenza vaccines in immunocompromised populations. The different strategies employed have included adjuvanted vaccines, high-dose vaccines, booster doses, intradermal vaccination, and temporary discontinuation of immunosuppressant treatment regimens. High-dose trivalent, inactivated, split-virus influenza vaccine (IIV3-HD) is so far one of the leading strategies for improving vaccine responses in HIV patients, transplant patients, and persons receiving immunosuppressant therapies for inflammatory diseases. Several studies in these populations have shown stronger humoral responses with IIV3-HD than existing standard-dose trivalent vaccine, and comparable safety. Accordingly, some scientific societies have stated that high-dose influenza vaccine could be a preferred option for immunocompromised patients. However, larger randomized controlled studies are needed to validate relative immunogenicity and safety of IIV3-HD and other enhanced vaccines and vaccination strategies in immunocompromised individuals.

Pre-existing Hemagglutinin Stalk Antibodies Correlate with Protection of Lower Respiratory Symptoms in Flu-Infected Transplant Patients

Hemagglutination-inhibitory antibodies are usually highly strain specific with little effect on infection with drifted or shifted strains. The significance of broadly cross-reactive non-HAI anti-influenza antibodies against conserved domains of virus glycoproteins, such as the hemagglutinin (HA) stalk, is of great interest. We characterize a cohort of 40 H1N1pmd09 influenza-infected patients and identify lower respiratory symptoms (LRSs) as a predictor for development of pneumonia. A binomial logistic regression of log10 pre-existing antibody values shows that the probability of LRS occurrence decreased with increased anti-HA full-length and stalk antibody ELISA titers. However, a multilevel logistic regression model adjusted by other potential serocorrelates demonstrates that only antibodies directed against the stalk of HA correlate with protection from lower respiratory infection, limiting disease progression. Our predictive model indicates that a threshold of protective immunity based on broadly cross-reactive HA stalk antibodies could be feasible.

Effect of Influenza Vaccination Inducing Antibody Mediated Rejection in Solid Organ Transplant Recipients

Introduction

Our goal was to study whether influenza vaccination induced antibody mediated rejection in a large cohort of solid organ transplant recipients (SOTR).

Methods

Serum anti-Human Leukocyte Antigen (HLA) antibodies were determined using class I and class II antibody-coated latex beads (FlowPRA^TM Screening Test) by flow cytometry. Anti-HLA antibody specificity was determined using the single-antigen bead flow cytometry (SAFC) assay and assignation of donor specific antibodies (DSA) was performed by virtual-crossmatch.

Results

We studied a cohort of 490 SOTR that received an influenza vaccination from 2009 to 2013: 110 (22.4%) received the pandemic adjuvanted vaccine, 59 (12%) within the first 6 months post-transplantation, 185 (37.7%) more than 6 months after transplantation and 136 (27.7%) received two vaccination doses. Overall, no differences of anti-HLA antibodies were found after immunization in patients that received the adjuvanted vaccine, within the first 6 months post-transplantation, or based on the type of organ transplanted. However, the second immunization dose increased the percentage of patients positive for anti-HLA class I significantly compared with patients with one dose (14.6% vs. 3.8%; P = 0.003). Patients with pre-existing antibodies before vaccination (15.7% for anti-HLA class I and 15.9% for class II) did not increase reactivity after immunization. A group of 75 (14.4%) patients developed de novo anti-HLA antibodies, however, only 5 (1.02%) of them were DSA, and none experienced allograft rejection. Only two (0.4%) patients were diagnosed with graft rejection with favorable outcomes and neither of them developed DSA.

Conclusion

Our results suggest that influenza vaccination is not associated with graft rejection in this cohort of SOTR.

Inactivated influenza vaccine does not reduce all cause respiratory illness in children with pre-existing medical conditions

BACKGROUND

The effectiveness of inactivated influenza vaccine (IIV) immunization in preventing all cause respiratory illness (RI) in children with pre-existing medical conditions has not been fully established and varies from season to season. This study aims to quantify the overall impact of IIV immunization on primary care attended RI episodes in children with pre-existing medical conditions, using robust observational data spanning twelve influenza seasons.

METHODS

Electronic records of IIV eligible children aged 6 months to 18 years were extracted from primary care databases over the years 2004-2015. IIV eligibility criteria according to Dutch guidelines included (chronic) respiratory and cardiovascular disease and diabetes mellitus. For each year, information on IIV immunization status, primary care attended RI episodes (including influenza, acute respiratory tract infections and asthma exacerbations) and potential confounders were collected. Generalized estimating equations were used to model the association between IIV status and occurrence of at least one RI episode during the influenza epidemic period with "current year immunized" as reference group. Robustness of findings were assessed by performing various sensitivity analyzes in which (i) seasons with a mismatch between the dominant circulating influenza virus and vaccine strain were excluded, (ii) influenza periods were further restricted to weeks with at least 30% influenza virus positive specimens in sentinel surveillance (instead of 5%), (iii) propensity scores were used to adjust for confounding.

RESULTS

In total, 11,797 children (follow-up duration: 38,701 child-years) were eligible for IIV for ≥ one season with 29% immunized at least once. The adjusted odds for primary care attended RI episodes during the influenza epidemic period did not differ between current season immunized versus not immunized children (adjusted OR:1.01; 95%CI:0.90-1.13). The various sensitivity analysis showed comparable results.

CONCLUSIONS

IIV immunization in children with pre-existing medical conditions does not reduce all cause RI episodes encountered in primary care during the influenza season.

Influenza vaccine strategies for solid organ transplant recipients

PURPOSE OF REVIEW

The aim of this study was to highlight recent evidence on important aspects of influenza vaccination in solid organ transplant recipients.

RECENT FINDINGS

Influenza vaccine is the most evaluated vaccine in transplant recipients. The immunogenicity of the vaccine is suboptimal after transplantation. Newer formulations such as inactivated unadjuvanted high-dose influenza vaccine and the administration of a booster dose within the same season have shown to increase response rates. Intradermal vaccination and adjuvanted vaccines did not show clear benefit over standard influenza vaccines. Recent studies in transplant recipients do not suggest a higher risk for allograft rejection, neither after vaccination with a standard influenza vaccine nor after the administration of nonstandard formulation (high-dose, adjuvanted vaccines), routes (intradermally) or a booster dose. Nevertheless, influenza vaccine coverage in transplant recipients is still unsatisfactory low, potentially due to misinterpretation of risks and benefits.

SUMMARY

Annual influenza vaccination is well tolerated and is an important part of long-term care of solid organ transplant recipients.

Prevention and Treatment of Respiratory Virus Infection

There is increasing recognition of infections caused by respiratory viruses (RVs) as a major cause of morbidity and mortality in solid organ transplant (SOT) recipients, especially within the thoracic and pediatric population. In addition to their direct, cytopathic, and tissue-invasive effects, RVs can create an inflammatory environment, autoimmune responses, resulting in acute and chronic rejection, although this relationship remains controversial. A laboratory diagnosis in SOT with respiratory syndrome should be performed with nucleic acid amplification tests on respiratory specimens, mainly nasopharyngeal swabs (NPS) and bronchoalveolar lavage (BAL). Treatment options remain limited and consist of supportive care, reduction of immunosuppression, and, if available, antiviral therapy. The use of immunomodulatory agents remains a clinical dilemma. Since treatment options for RVs are limited, maximizing prevention measures against viral infections in SOT is mandatory. The main preventive strategy against influenza remains the administration of yearly inactivated influenza vaccine in all SOT. The aim of this review is to summarize the evidence-based recommendations on the diagnostic, preventive, and therapeutic strategies to decrease the burden of RV infections in SOT recipients.

Immunogenicity and safety of double versus standard dose of the seasonal influenza vaccine in solid-organ transplant recipients: A randomized controlled trial

BACKGROUND

The use of vaccines with higher doses of antigen is an attractive strategy to improve the immunogenicity of influenza vaccination in transplant recipients. However, the effect of vaccination with a double-dose (DD) containing 30 µg of antigen in this population remains unknown.

METHODS

We performed a randomized controlled trial to compare the immunogenicity and safety of DD (30 µg) vs. standard dose (SD, 15 µg) of a trivalent inactivated influenza vaccine in kidney and liver transplant recipients. Immunogenicity was assessed by hemagglutination-inhibition assay. Vaccine response was defined as seroconversion to at least one viral strain 2 weeks after vaccination and seroprotection as a titer ≥40.

RESULTS

Sixty-three kidney and 16 liver transplant recipients were enrolled. Forty patients received the DD and 39 the SD vaccine. Overall, 40% of patients in the DD compared to 26% in the SD group (P = 0.174) responded to vaccine. In the DD arm, more patients were seroprotected to all viral strains after vaccination (88% vs 69%, P = 0.048). Post vaccination geometric mean titers of antibodies were 131.9 vs. 89.7 (P = 0.187) for H1N1, 185.4 vs. 138.7 (P = 0.182) for H3N2, and 96.6 vs. 68.8 (P = 0.081) for influenza B with the DD vs. SD. In both groups, most of the adverse events were mild and no vaccine-related severe adverse events were observed.

CONCLUSION

Double-dose influenza vaccine is safe and may increase antibody response in transplant recipients. In this population, DD vaccination could be an alternative when high-dose vaccine is not available. NCT02746783.

Seasonal influenza vaccine in immunocompromised persons

Immunocompromised persons are at high risk of complications from influenza infection. This population includes those with solid organ transplants, hematopoietic stem cell transplants, solid cancers and hematologic malignancy as well as those with autoimmune conditions receiving biologic therapies. In this review, we discuss the impact of influenza infection and evidence for vaccine effectiveness and immunogenicity. Overall, lower respiratory disease from influenza is common; however, vaccine immunogenicity is low. Despite this, in some populations, influenza vaccine has demonstrated effectiveness in reducing severe disease. Various strategies to improve influenza vaccine immunogenicity have been attempted including two vaccine doses in the same influenza season, intradermal, adjuvanted, and high-dose vaccines. The timing of influenza vaccine is also important to achieve optimal immunogenicity. Given the suboptimal immunogenicity, family members and healthcare professionals involved in the care of these populations should be vaccinated. Health care professional recommendation for vaccination is an important factor in vaccine coverage.

Two Doses of Inactivated Influenza Vaccine Improve Immune Response in Solid Organ Transplant Recipients: Results of TRANSGRIPE 1-2, a Randomized Controlled Clinical Trial

Background

Influenza vaccine effectiveness is not optimal in solid organ transplant recipients (SOTR). We hypothesized that a booster dose might increase it.

Methods

TRANSGRIPE 1-2 is a phase 3, randomized, controlled, multicenter, open-label clinical trial. Patients were randomly assigned (1:1 stratified by study site, type of organ, and time since transplantation) to receive 1 dose (control group) or 2 doses (booster group) of the influenza vaccine 5 weeks apart.

Results

A total of 499 SOTR were enrolled. Although seroconversion at 10 weeks did not meet significance in the modified intention-to-treat population, seroconversion rates were significantly higher in the booster arm for the per-protocol population (53.8% vs 37.6% for influenza A(H1N1)pdm; 48.1% vs 32.3% for influenza A(H3N2); and 90.7% vs 75% for influenza B; P < .05). Furthermore, seroprotection at 10 weeks was higher in the booster group: 54% vs 43.2% for A(H1N1)pdm; 56.9% vs 45.5% for A(H3N2); and 83.4% vs 71.8% for influenza B (P < .05). The number needed to treat to seroprotect 1 patient was <10. The clinical efficacy (99.2% vs 98.8%) and serious adverse events (6.4% vs 7.5%) were similar for both groups.

Conclusions

In SOTR, a booster strategy 5 weeks after standard influenza vaccination is safe and effective and induces an increased antibody response compared with standard influenza vaccination consisting of a single dose.

Clinical Trials Registration

EudraCT (2011-003243-21).

Determinants of influenza vaccination among solid organ transplant recipients attending Sicilian reference center

Among solid organ transplant recipients, influenza infection is commonly associated with higher morbidity and mortality than immunocompetent hosts. Therefore, in these subjects influenza vaccination is of paramount importance. The main objective of the study was to assess compliance to vaccination and analyze factors associated with influenza vaccination of solid organ transplant recipients admitted to the Sicilian solid organ transplant Reference Center IRCCS-ISMETT in Palermo during 2014-2015 influenza season. Thirty one (37.8%) out of 82 solid organ transplant recipients were vaccinated against influenza. The main reason for vaccination refusal was fear of adverse reaction (n = 16, 31.4%), impaired health status (n = 14, 27.4%) and low vaccine efficacy (n = 10, 19.6%). Vaccinated solid organ transplant recipients compare with unvaccinated had smaller hospital admissions for infectious respiratory diseases (9.7% Vs 23.5%) during surveillance period. On multivariate analysis the factors positively associated with influenza vaccination were the advice of Reference Center physicians (OR 53.4, p < 0.001) and to perform vaccine against pneumococcus (OR 7.0, p = 0.016). This study showed that Reference Center physicians play a key role on vaccine communication and recommendation for patients at risk and it underlines the effectiveness of influenza vaccination in solid organ transplant recipients. However, it remains that, although physician advice resulted a strong determinant for vaccination, influenza vaccination coverage in this subset of population remains still unsatisfactory.

Influenza vaccination status and outcomes among influenza-associated hospitalizations in Columbus, Ohio (2012-2015)

Prior studies suggest that the influenza vaccine is protective against some outcomes in hospitalized patients infected with influenza despite vaccination. We utilized surveillance data from Columbus, Ohio to investigate this association over multiple influenza seasons and age groups. Data on laboratory-confirmed influenza-associated hospitalizations were collected as a part of the Influenza Hospitalization Surveillance Project for the 2012-2013, 2013-2014, and 2014-2015 influenza seasons. The association between influenza vaccination status was examined in relation to the outcomes of severe influenza and diagnosis of pneumonia among patients receiving antiviral treatment. Data were analyzed using multivariable logistic regression. We observed no overall association between influenza vaccination status and severe influenza among hospitalized patients. During the 2013-2014 season, those who were vaccinated were 41% less likely to be diagnosed with pneumonia compared with those who were unvaccinated (OR = 0·59 95% CI 0·41-0·86). The influenza vaccine may provide a secondary preventive function against pneumonia among influenza cases requiring hospitalization. However, a protective effect was only observed in 2013-2014, an influenza H1N1 dominant year. Differences in circulating influenza virus strains and vaccine matching to the circulating strains during influenza seasons may impact this association.

Influenza vaccine effectiveness among high-risk groups: A systematic literature review and meta-analysis of case-control and cohort studies

Vaccination represents the most effective intervention to prevent infection, hospitalization and mortality due to influenza. This meta-analysis quantifies data reporting influenza vaccine effectiveness (VE) on influenza visits and hospitalizations of case-control and cohort studies among high-risk groups.

A systematic literature review including original articles published between 2007 and 2016, using a protocol registered on Prospero with No. 42017054854, and a meta-analysis were conducted.

For 3 high-risk groups (subjects with underlying health conditions, pregnant women and health care workers) only a qualitative evaluation was performed. The VE quantitative analysis demonstrated a clear significant overall effect of 39% (95%CI: 32–46%) for visits and 57% (95%CI: 30–74%) for hospitalization among children. Considering the elderly influenza VE had a clear effect of 25% (95%CI: 6–40%) for visits and 14% (95%CI: 7–21%; p<0.001) for hospitalization.

This study showed the high VE of influenza vaccination among high-risk groups, representing a tool for public health decision-makers to develop evidence-based preventive interventions to avoid influenza outcomes.

The Impact of Infection on Chronic Allograft Dysfunction and Allograft Survival After Solid Organ Transplantation

Infectious diseases after solid organ transplantation (SOT) are a significant cause of morbidity and reduced allograft and patient survival; however, the influence of infection on the development of chronic allograft dysfunction has not been completely delineated. Some viral infections appear to affect allograft function by both inducing direct tissue damage and immunologically related injury, including acute rejection. In particular, this has been observed for cytomegalovirus (CMV) infection in all SOT recipients and for BK virus infection in kidney transplant recipients, for community-acquired respiratory viruses in lung transplant recipients, and for hepatitis C virus in liver transplant recipients. The impact of bacterial and fungal infections is less clear, but bacterial urinary tract infections and respiratory tract colonization by Pseudomonas aeruginosa and Aspergillus spp appear to be correlated with higher rates of chronic allograft dysfunction in kidney and lung transplant recipients, respectively. Evidence supports the beneficial effects of the use of antiviral prophylaxis for CMV in improving allograft function and survival in SOT recipients. Nevertheless, there is still a need for prospective interventional trials assessing the potential effects of preventive and therapeutic strategies against bacterial and fungal infection for reducing or delaying the development of chronic allograft dysfunction.

Does Influenza Vaccination Modify Influenza Severity? Data on Older Adults Hospitalized With Influenza During the 2012-2013 Season in the United States

BACKGROUND

Some studies suggest that influenza vaccination might be protective against severe influenza outcomes in vaccinated persons who become infected. We used data from a large surveillance network to further investigate the effect of influenza vaccination on influenza severity in adults aged ≥50 years who were hospitalized with laboratory-confirmed influenza.

METHODS

We analyzed influenza vaccination and influenza severity using Influenza Hospitalization Surveillance Network (FluSurv-NET) data for the 2012-2013 influenza season. Intensive care unit (ICU) admission, death, diagnosis of pneumonia, and hospital and ICU lengths of stay served as measures of disease severity. Data were analyzed by multivariable logistic regression, parametric survival models, and propensity score matching (PSM).

RESULTS

Overall, no differences in severity were observed in the multivariable logistic regression model. Using PSM, adults aged 50-64 years (but not other age groups) who were vaccinated against influenza had a shorter length of ICU stay than those who were unvaccinated (hazard ratio for discharge, 1.84; 95% confidence interval, 1.12-3.01).

CONCLUSIONS

Our findings show a modest effect of influenza vaccination on disease severity. Analysis of data from seasons with different predominant strains and higher estimates of vaccine effectiveness are needed.

Efficacy and safety of a booster dose of influenza vaccination in solid organ transplant recipients, TRANSGRIPE 1-2: study protocol for a multicenter, randomized, controlled clinical trial

BACKGROUND

Despite administration of annual influenza vaccination, influenza-associated complications in transplant recipients continue to be an important cause of hospitalization and death. Although influenza vaccination has been proven to be the most effective measure to reduce influenza infection after transplantation, transplant recipients are still vulnerable to influenza infections, with lower serological responses to vaccination compared to the general population. In order to assess the efficacy and safety of an alternative immunization scheme for solid organ transplant recipients, the TRANSGRIPE1-2 Study Group aimed to test a booster dose administration 5 weeks after the standard vaccination. The primary objective of this trial was to compare short-term and long-term neutralizing antibody immunogenicity of a booster dose of influenza vaccination to the standard single-dose immunization scheme. Secondary objectives included the evaluation of the efficacy and/or safety, cellular immune response, incidence of influenza infection, graft rejection, retransplant and mortality rates.

METHODS/DESIGN

This phase III, randomized, controlled, open-label clinical trial was conducted between October 2012 and December 2013 in 12 Spanish public referral hospitals. Solid organ transplant recipients (liver, kidney, heart or lung), older than 16 years of age more than 30 days after transplantation were eligible to participate. Patients (N = 514) were stratified 1:1 by center, type of organ and time after transplantation and who either received the standard single dose (n = 257) or were treated according to a novel influenza vaccination schedule comprising the administration of a booster dose 5 weeks after standard vaccination (n = 254). Seroconversion rates were measured as a determinant of protection against influenza (main outcome). Efficacy and safety outcomes were followed until 1 year after influenza vaccination with assessment of short-term (0, 5, 10 and 15 weeks) and long-term (12 months) results. Intention-to-treat, per-protocol and safety analyses will be performed.

DISCUSSION

This trial will increase knowledge about the safety and efficacy of a booster dose of influenza vaccine in solid organ transplant recipients. At the time the manuscript was submitted for publication, trial recruitment was closed with a total of 499 participants included during a 2-month period (within the seasonal influenza vaccination campaign).

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01761435 (registered 13 December 2012). EudraCT Identifier: 2011-003243-21 (registered 4 July 2011).

Impact of immunosuppression on recall immune responses to influenza vaccination in stable renal transplant recipients

BACKGROUND

The recommendation by the American Society of Transplantation for annual trivalent inactivated influenza vaccination greater than 3 to 6 months post-kidney transplantation provides a unique opportunity to test the in vivo impact of immunosuppression on recall T- and B-cell responses to influenza vaccination.

METHODS

This study took advantage of recent breakthroughs in the single-cell quantification of human peripheral blood B-cell responses to prospectively evaluate both B- and T-cell responses to the seasonal (2010 and 2011) influenza vaccine in 23 stable renal transplant recipients and 22 healthy controls.

RESULTS AND CONCLUSION

The results demonstrate that the early B-cell response to influenza vaccination, quantified by the frequency of influenza-specific antibody-secreting cells (ASC) in peripheral blood, was significantly reduced in stable transplant recipients compared to healthy controls. The magnitude of the seroresponse and the rate of seroconversion were also blunted. The influenza-specific interferon-gamma (IFNγ) T-cell response was significantly reduced in transplant recipients; however, there was no correlation between the magnitude of the influenza-specific IgG ASC and IFNγ responses. The induction of memory T- and B-cell responses to influenza vaccination supports the recommendation to vaccinate while the blunted responses demonstrate the efficacy of immunosuppression in controlling memory responses individual transplant recipients.

Influenza vaccination and humoral alloimmunity in solid organ transplant recipients

Annual influenza vaccination is recommended in solid organ transplant (SOT) recipients. However, concerns have been raised about the impact of vaccination on antigraft alloimmunity. We evaluated the humoral alloimmune responses to influenza vaccination in a cohort of SOT recipients between October 2008 and December 2011. Anti-HLA antibodies were measured before and 4-8 weeks after influenza vaccination using a solid-phase assay. Overall, 169 SOT recipients were included (kidney = 136, lung = 26, liver = 3, and combined = 4). Five (2.9%) of 169 patients developed de novo anti-HLA antibodies after vaccination, including one patient who developed donor-specific antibodies (DSA) 8 months after vaccination. In patients with pre-existing anti-HLA antibodies, median MFI was not significantly different before and after vaccination (P = 0.73 for class I and P = 0.20 for class II anti-HLA antibodies) and no development of de novo DSA was observed. Five episodes of rejection (2.9%) were observed within 12 months after vaccination, and only one patient had de novo anti-HLA antibodies. The incidence of development of anti-HLA antibodies after influenza vaccination in our cohort of SOT recipients was very low. Our findings indicate that influenza vaccination is safe and does not trigger humoral alloimmune responses in SOT recipients.

Infections in transplant patients

Recipients of solid organ transplants (SOT) need primary care providers (PCPs) who are familiar with their unique needs and understand the lifelong infectious risks faced by SOT patients because of their need for lifelong immunosuppressive medications. SOT recipients can present with atypical and muted manifestations of infections, for which the knowledgable PCP will initiate a comprehensive evaluation. The goal of this article is to familiarize PCPs with the infectious challenges facing SOT patients. General concepts are reviewed, and a series of patient cases described that illustrate the specific learning points based on common presenting clinical symptoms.

Management of influenza infection in solid-organ transplant recipients: consensus statement of the Group for the Study of Infection in Transplant Recipients (GESITRA) of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) and the Spanish Network for Research in Infectious Diseases (REIPI)

BACKGROUND

Solid organ transplant (SOT) recipients are at greater risk than the general population for complications and mortality from influenza infection.

METHODS

Researchers and clinicians with experience in SOT infections have developed this consensus document in collaboration with several Spanish scientific societies and study networks related to transplant management. We conducted a systematic review to assess the management and prevention of influenza infection in SOT recipients. Evidence levels based on the available literature are given for each recommendation. This article was written in accordance with international recommendations on consensus statements and the recommendations of the Appraisal of Guidelines for Research and Evaluation II (AGREE II).

RESULTS

Recommendations are provided on the procurement of organs from donors with suspected or confirmed influenza infection. We highlight the importance of the possibility of influenza infection in any SOT recipient presenting upper or lower respiratory symptoms, including pneumonia. The importance of early antiviral treatment of SOT recipients with suspected or confirmed influenza infection and the necessity of annual influenza vaccination are emphasized. The microbiological techniques for diagnosis of influenza infection are reviewed. Guidelines for the use of antiviral prophylaxis in inpatients and outpatients are provided. Recommendations for household contacts of SOT recipients with influenza infection and health care workers in close contact with transplant patients are also included. Finally antiviral dose adjustment guidelines are presented for cases of impaired renal function and for pediatric populations.

CONCLUSIONS

The latest scientific information available regarding influenza infection in the context of SOT is incorporated into this document.