Infectious complications after hematopoietic stem cell transplantation: current status and future perspectives in Korea

Early bacteremia following allogeneic hematopoietic stem cell transplantation without antibiotic prophylaxis: epidemiology and antimicrobial resistance

OBJECTIVE

Bacteremia is a serious complication in patients undergoing allogeneic hematopoietic stem cell transplantation. The aim of this study was to determine the frequency, epidemiological profile, and risk factors of bacteremia early after allogeneic hematopoietic stem cell transplantation.

METHODS

An observational descriptive retrospective study was conducted in patients who received transplants between January 2016 and December 2021. Early bacteremia was defined as blood stream infection occurring between Day 0 and Day 100 after transplantation.

RESULTS

Forty episodes of early bacteremia occurred in 36/245 transplanted patients. Fifteen episodes (37.5%) were due to gram-positive bacteria and 25 (62.5%) to gram-negative bacteria. The most frequent species isolated were coagulase negative staphylococci (CoNS) in gram-positive bacteremia (n = 8/15), and Klebsiella species (8/25) and Pseudomonas species (8/25) in gram-negative bacteremia. Twenty-nine episodes of bacteremia (72.5%) occurred during the first 30 days after transplantation with a median time of nine days (range: 0-90 days). Coagulase negative staphylococci were methicillin-resistant in 75% of cases, the only Staphylococcus aureus isolated was methicillin-resistant. All gram-positive bacilli were penicillin-resistant. Gram-negative bacilli were multidrug resistant in 61.5% of cases. In multivariate analysis, bone marrow as source of graft (p-value = 0.02) and cytomegalovirus reactivation (p-value = 0.02) were significantly associated with an increased risk of bacteremia. Mortality attributable to bacteremia was 2.8%. The one-year overall survival was not significantly different between those with and without bacteremia.

CONCLUSIONS

Bacteremia was more frequent within the first 30 days after transplantation indicating the crucial role of neutropenia. An increase in multidrug resistant gram-negative bacteremia was noted.

Effectiveness of Pre-Transplant Screening for High-Priority Multidrug-Resistant Pathogens on Pre-Engraftment Infections After Hematopoietic Stem Cell Transplantation

Objective

Owing to the rising incidence of multidrug-resistant organisms (MDRO) and the high mortality rates associated with such bacterial infections post-hematopoietic stem cell transplantation (HSCT), we investigated the MDRO colonization rate prior to transplantation using an active surveillance approach and determined its impact on subsequent infection during the pre-engraftment period.

Methods

A single-center observational study was conducted, and surveillance cultures from multiple body sites, including the rectum, nasal cavity, and groin, were performed at admission to determine MDRO colonization. Serological tests were used to detect certain viruses and toxoplasmosis before HSCT.

Results

In the pre-transplant setting, 59 MDRO were recovered from the 40 HSCT recipients. Of the 59 isolates recovered from one or more body sites, 29 were positive for methicillin-resistant Staphylococcus aureus (MRSA), 7 for carbapenem-resistant Enterobacterales (CRE), and 23 were positive for extended-spectrum β-lactamase (ESBLs). Serological assessment before HSCT revealed active or reactivation of latent infection with cytomegalovirus (7.5%), Epstein-Barr virus (EBV; 5%), and Toxoplasma gondii (2.5%) among HSCT patients. In terms of factors associated with pre-engraftment infections, the type of transplant (p=0.04) was statistically significant, whereas other factors, such as age, sex, and underlying conditions, were not. In post-transplant settings, bloodstream infections (BSIs) were documented in 2 allogeneic HSCT patients (5%), and the isolated microorganisms were ESBL-producing E. coli and non-MDR Acinetobacter baumannii.

Conclusion

Active screening cultures are a helpful tool for identifying patients colonized by MDRO or relevant viruses before HSCT, and for predicting those at risk of developing subsequent pre-engraftment infections. Additionally, active screening may aid in predicting those who are likely to develop subsequent pre-engraftment infections Our findings highlight the importance of pre-transplant screening for high-priority multidrug-resistant pathogens and the application of infection control interventions after HSCT.

Clinical Implementation of β-Tubulin Gene-Based Aspergillus Polymerase Chain Reaction for Enhanced Aspergillus Diagnosis in Patients with Hematologic Diseases: A Prospective Observational Study

The β-tubulin (benA) gene is a promising target for the identification of Aspergillus species. Assessment of the clinical implementation and performance of benA gene-based Aspergillus polymerase chain reaction (PCR) remains warranted. In this study, we assessed the analytical performance of the BenA probe PCR in comparison with the Aspergenius kit. We prospectively collected bronchoalveolar lavage (BAL) fluid via diagnostic bronchoscopy from adult patients with hematologic diseases. BenA gene-based multiplex real-time PCR and sequential melting temperature analysis were performed to detect the azole resistance of Aspergillus fumigatus. In total, 76 BAL fluids in 75 patients suspicious of invasive pulmonary aspergillosis (IPA) were collected. Before the application of PCR, the prevalence of proven and probable IPA was 32.9%. However, after implementing the benA gene-based PCR, 15.8% (12 out of 76) of potential IPA cases were reclassified as probable IPA. The analytical performance of the BenA probe PCR in BAL samples was comparable to that of the Aspergenius kit. The diagnostic performance was as follows: sensitivity, 52.0%; specificity, 64.7%; positive predictive value, 41.9%; negative predictive value, 73.3%; positive likelihood ratio, 1.473; and negative likelihood ratio, 0.741. Moreover, benA gene-based Aspergillus PCR discriminated all major sections of Aspergillus, including cryptic species such as Aspergillus tubingensis. Sequential melting temperature analysis successfully detected 2 isolates (15.4%) of A. fumigatus carrying resistant mutations. BenA gene-based Aspergillus PCR with melting temperature analysis enhances diagnostic accuracy and detects not only cryptic species but also resistant mutations of A. fumigatus. It shows promise for clinical applications in the diagnosis of IPA.

Symptoms of posttraumatic stress disorder and adjustment disorder in hematological cancer patients with different treatment regimes

BACKGROUND

Symptoms of posttraumatic stress disorder (PTSD) and adjustment disorder (AjD) are common in hematological cancer patients as they face severe stressors during their serious disease and often intensive treatment, such as stem cell transplantation (SCT). Aims of the present study were to provide frequency and risk factors for PTSD and AjD based on updated diagnostic criteria that are lacking to date.

MATERIAL AND METHODS

In a cross-sectional study, hematological cancer patients were assessed for stressor-related symptoms via validated self-report questionnaires based on updated criteria for PTSD (PCL-5) and AjD (ADMN-20). Frequency and symptom severity were estimated among the total sample and SCT subgroups (allogeneic, autologous, no SCT). SCT subgroups were compared using Chi-squared-tests and ANOVAs. Linear regression models investigated sociodemographic and medical factors associated with symptomatology.

RESULTS

In total, 291 patients were included (response rate: 58%). 26 (9.3%), 66 (23.7%) and 40 (14.2%) patients met criteria for cancer-related PTSD, subthreshold PTSD and AjD, respectively. Symptom severity and frequency of criteria-based PTSD and AjD did not differ between SCT subgroups (all p > 0.05). Factors associated with elevated symptomatology were younger age (PTSD: p < 0.001; AjD: p = 0.02), physical comorbidity (PTSD: p < 0.001; AjD: p < 0.001) and active disease (PTSD: p = 0.12; AjD: p = 0.03).

CONCLUSION

Based on new criteria, a considerable part of hematological cancer patients reports PTSD and AjD symptoms. Younger patients and patients with physical symptom burden might be particularly at risk and need to be monitored closely to enable effective treatment at an early stage.

Incidence and risk factors of opportunistic infections after autologous stem cell transplantation: a nationwide, population-based cohort study in Korea

Several guidelines classify autologous stem cell transplantation (ASCT) as a low to intermediate risk group for infection. In a nationwide population-based study, using the Korean Health Insurance Review and Assessment Service database, patients with lymphoma and multiple myeloma (MM) who underwent ASCT from 2002 to 2016 were retrospectively analyzed. Cumulative incidence rates (CIRs) and risk factors of opportunistic infections were investigated. CIRs of fungal, Varicella zoster virus (VZV), cytomegalovirus (CMV), and Pneumocystis jirovecii infections in lymphoma were 7.9%, 16.0%, 7.4%, and 5.1%, respectively, and CIRs in MM were 6.3%, 19.1%, 4.2%, and 5.6%, respectively. Fungal infection was significantly higher in patients with previous infection (Hazard ratio (HR) 2.003, p = 0.005) in lymphoma. Incidence of CMV infection was significantly higher in patients with prior CMV infection: HR 4.920, p < 0.001 (lymphoma); HR 3.022, p = 0.030 (MM). VZV infection was significantly lower in patients receiving prophylaxis: HR 0.082, p < 0.001 (lymphoma); HR 0.096, p < 0.001 (MM). For P. jirovecii infection, busulfex and melphalan conditioning (HR 1.875, p = 0.032) and previous P. jirovecii infection (HR 4.810, p < 0.001) had a higher incidence in MM. Patients who underwent ASCT should receive VZV prophylaxis and prophylaxis for fungal and P. jirovecii may be considered in patients with previous same infection.

Oral and post-transplantation infectious status in patients with hematopoietic stem cell transplants: A prospective observational study

OBJECTIVE

Infectious status may be life threatening in hematopoietic stem cell transplant (HSCT) recipients. The aim of this study was to evaluate the effect of oral status on infectious conditions during the neutropenic phase after HSCT.

STUDY DESIGN

Seventy patients with various hematologic malignancies were involved. Before HSCT, oral and periodontal examination, including the number of teeth and decayed, missing, and filled teeth index (DMFT); visible plaque (%); bleeding on probing (BOP [%]); clinical attachment level; and probing depth (PD) values were collected. Daily blood cultures were collected and analyzed in terms of infection-related parameters, including febrile neutropenia (FN), bacteremia, and C-reactive protein (CRP) during the neutropenic phase of HSCT.

RESULTS

Forty-two patients (60%) received autologous and 28 (40%) allogeneic HSCT. In both groups, patients without FN after HSCT had significantly lower DMFT index scores and fewer sites with PD ≥4 mm (P < .05). However, bacteremia, FN, and CRP were similar in patients with periodontitis compared with non-periodontitis patients (P > .05).

CONCLUSIONS

The results suggest that periodontal status may not significantly impact the infection-related parameters in patients treated for HSCT. However, DMFT and the prevalence of sites with PD ≥4 mm may be involved in febrile neutropenia.

Clinical characteristics, drug resistance and death risk factors of Burkholderia cepacia infection in hematopoietic stem cell transplant patients

Background

Burkholderia cepacia (BC) has been detected more and more in infected patients in recent years. However, as a high-risk population, the clinical characteristics and prognosis of BC infection in hematopoietic stem cell transplantation (HSCT) patients have not been reported. The purpose of this study is to obtain data that will help fill in the gaps in this field, provide evidence for reducing the mortality rate of BC infection in HSCT patients, and guide the use of antibiotics in the future.

Methods

Electronic medical records of patients with BC infection who underwent HSCT in Xiangya Hospital of Central South University from September 1, 2015 to August 31, 2021 were collected. At the same time, 1:1 case–control matching was conducted according to gender, age and disease type. Comparisons between patients with/without BC infection and respiratory failure were made respectively, and the sensitivity of BC to five clinically commonly used antibiotics was also evaluated. Univariate and multivariate analyses were performed to identify independent risk factors for death.

Results

The most common site of BC infection in HSCT patients was the lung (75%). Although BC infection rate (3.74%) and antibiotic resistance were not significant, it was closely associated with a higher risk of death (P = 0.022), which even further increased to 90.9% when combined with respiratory failure (P = 0.008). Procalcitonin > 10 µg/L (HR = 40.88, 95% CI 6.51–256.63, P = 0.000) and septic shock (HR = 4.08, 95% CI 1.02–16.33, P = 0.047) were two independent risk factors for death.

Conclusion

HSCT patients with BC infection are in critical condition, and the management of respiratory infection should be especially strengthened to improve the prognosis of these patients.

Assessing the Efficacy of Alkylating Agent Regimens in the Treatment of Infantile Malignant Osteopetrosis: Cyclophosphamide, Busulfan, or Thiotepa

Infantile malignant osteopetrosis is a debilitating disease that requires total bone marrow irradiation and transplant procedures for patients to survive. The major complication of this procedure is graft vs host disease (GVHD), followed by infections and end organ toxicity. Therefore, current research efforts into treatment mainly aim to reduce GVHD while limiting infections and organ toxicity. Different regimens of alkylating agents have been used to try to reduce GVHD. The most common regimen is cyclophosphamide (Cy) with busulfan (Bu), followed by Cy with Bu and thiotepa (Thio). This meta-analysis aimed to evaluate the efficacy of different treatments by comparing mortality and morbidity causes and rates across groups. The mean one-year survival rate for the Cy, Bu, Thio regimen studies in the human leukocyte antigen (HLA) unmatched group (45.01%) was statistically lower than the one-year survival rate for the studies using just a Cy, Bu regimen (70.8%) in the HLA unmatched studies (p<0.00142). The one-year survival in the studies which had HLA-matched donors was 80.56%, which is statistically higher (p<0.001) than the one-year survival in the HLA-unmatched studies (53.96%), indicating a benefit of finding HLA-matched donors. It seems that price and availability could be a factor in the widespread use of Cy.

A comparison of four drug-drug interaction databases for patients undergoing haematopoietic stem cell transplantation

WHAT IS KNOWN AND OBJECTIVE

Patients who have undergone haematopoietic stem cell transplantation are prone to drug-drug interactions due to polypharmacy. Drug-drug interaction databases are essential tools for identifying interactions in this patient group. However, drug-drug interaction checkers, which help manage interactions, may have disagreements about assessing the existence or severance of the interactions. The study aimed to determine differences among popular drug-drug interaction databases from several angles for patients who underwent haematopoietic stem cell transplantation.

METHODS

The 21-day treatment sheets of one hundred patients who underwent haematopoietic stem cell transplantation were examined in two subscription-based (Uptodate and Micromedex) and two open-access databases (Drugs.com and Epocrates) in terms of several categories two years in a row. Statistical analysis was utilized to understand the compatibility of databases in terms of severity scores, evidence levels, given references, and word counts in interaction reports. Fleiss' and Cohen's kappa statistics were used to analyse the databases' agreement levels.

RESULTS AND DISCUSSION

A total of 1393 and 1382 different drug-drug interactions were detected in subsequent versions of the databases, namely the 2021 and 2022 versions. The Fleiss kappa overall agreement among databases was slight. Uptodate and Micromedex showed fair agreement, and other database pairs showed slight agreement in severity ratings.

CONCLUSION

There was a poor agreement among databases for interactions seen in bone marrow transplantation patients. Therefore, it would be safer to use more than one database in daily practice. Further work needs to be done to understand the agreement level of databases for different types of interactions.

Advances in prophylaxis and treatment of invasive fungal infections: perspectives on hematologic diseases

Invasive fungal infections (IFIs) are common causes of mortality and morbidity in patients with hematologic diseases. Delayed initiation of antifungal treatment is related to mortality. Aspergillus sp. is the leading cause of IFI followed by Candida sp. Diagnosis is often challenging owing to variable conditions related to underlying diseases. Clinical suspect and prompt management is important. Imaging, biopsy, and non-culture-based tests must be considered together. New diagnostic procedures have been improved, including antigen-based assays and molecular detection of fungal DNA. Among hematologic diseases, patients with acute myeloid leukemia, myelodysplastic syndrome, recipients of hematopoietic stem cell transplantation are at high risk for IFIs. Antifungal prophylaxis is recommended for these high-risk patients. There are continuous attempts to achieve ideal management of IFIs. Scoring system for quality control has been developed with important recommendations of current guidelines. Higher adherence to guidelines is related to decreased mortality in IFIs.

QTc prolongation during levofloxacin and triazole combination chemoprophylaxis: Prevalence and predisposing risk factors in a cohort of hematopoietic cell transplantation recipients

BACKGROUND

QTc interval prolongation has been reported when combining fluoroquinolones and triazoles for chemoprophylaxis in cancer patients. Herein, we aimed to identify the prevalence and contributing factors to QTc prolongation in hematopoietic cell transplantation (HCT) recipients who received these agents during the neutropenic phase.

METHODS

This is a retrospective medical chart review conducted at a university hospital in Lebanon from 2017 to 2020. It included all adult HCT inpatients on antimicrobial prophylaxis with fluoroquinolones and triazoles and whose baseline ECG monitoring done prior to chemoprophylaxis administration, then on day-3 and day-6 of therapy, were available.

RESULTS

Overall, 68 HCT recipients met our inclusion criteria, of which 22% developed QTc prolongation. Based on bivariate analysis, female gender contributed to QTc prolongation (P = 0.001). There was a trend to QTc prolongation in patients with predisposing thyroid disease (P = 0.12), grade 2 vomiting and diarrhea (P = 0.16, P = 0.46, respectively), baseline hypokalemia (P = 0.18) and hypocalcemia (P = 0.3), hypomagnesemia on day-3 (P = 0.21) and day-6 hyponatremia (P = 0.36). Patients receiving two or more drugs with a known or probable risk of QTc prolongation (other than the fluoroquinolone/ triazole combination) were more prone to experience a prolonged QTc interval (P = 0.09). None of the patients that had QTc prolongation died or developed serious arrhythmias.

CONCLUSION

The prevalence of QTc prolongation was 22% among HCT recipients on fluoroquinolone and triazole prophylaxis, yet we did not identify any independent risk factors for this issue. None of the patients that had QTc interval prolongation died or developed serious arrhythmias.

Incidence, economic burden, and treatment of acute respiratory tract infection in hematopoietic stem cell transplantation recipients using real world data in Japan: a retrospective claims data analysis

AIMS

Acute respiratory tract infections (ARTIs) are common in hematopoietic stem cell transplantation (HSCT) recipients, however, data is limited regarding epidemiology and economic burden of ARTI in HSCT recipients in Japan. We evaluated the incidence of ARTI in HSCT recipients, associated economic burden, and ARTI-related treatments post-HSCT.

MATERIALS AND METHODS

Patients receiving HSCT between July 2017 and December 2018, and those enrolled in the JMDC Claims Database for ≥6 months before index month (month when latest medical procedure code of HSCT recorded) were included. The outcomes included demographics, ARTI incidence, healthcare resource utilization (HCRU), direct costs, and ARTI-related treatments.

RESULTS

In 330 analyzed patients, the ARTI incidence rate was 85.5% during total follow-up, consisting of post-HSCT hospitalization of mean 2.1 months and post-discharge periods of mean 17.6 months (post-HSCT hospitalization: 44.8%; post-discharge: 77.6%). For ARTI vs non-ARTI patients during post-HSCT hospitalization, length of hospitalization was significantly longer (mean [SD] months; 2.40 [1.73] vs 1.84 [1.09]; p = 0.0004), and median cost was significantly higher (JPY; 6,250,120.00 vs 4,774,570.00; p = 0.0096). The cost of outpatient visits during post-discharge periods, drug-related and non-drug-related costs of outpatient visits were generally higher for ARTI vs non-ARTI patients. In ARTI vs non-ARTI patients, utilization of any symptom relievers (decongestants, antitussives, and antipyretics), bronchodilators, immunoglobulin G, antibiotics, antivirals, and oxygen supply were numerically higher during post-HSCT hospitalization and post-discharge periods. The proportion of patients and mean prescription days for immunosuppressants during post-HSCT hospitalization were higher in ARTI vs non-ARTI patients.

LIMITATIONS

This administrative claims study lacks clinical data and contains only direct medical costs. Patients were retained if they had at least 1 month of enrollment post-HSCT.

CONCLUSIONS

In HSCT recipients, ARTI leads to substantial incremental HCRU and direct costs for management in real-world settings in Japan.

Prevalence and clinical course of upper airway respiratory virus infection in critically ill patients with hematologic malignancies

Background

The clinical significance of upper airway respiratory virus (RV) detection in patients with hematologic malignancies remains unclear. We aimed to investigate the association between upper airway RV detection and prognosis in critically ill patients with hematologic malignancies.

Methods

This retrospective observational study included 331 critically ill patients with hematologic malignancies who presented respiratory symptoms and their nasopharyngeal swab was tested using a multiplex PCR assay between January 2017 and December 2018. A logistic regression model was used to adjust for potential confounding factors in the association between assay positivity and in-hospital mortality.

Results

Among the 331 analyzed patients, RVs were detected in 29.0%. The overall mortality rates in the intensive care unit and hospital were 56.8% and 65.9%, respectively. Positive upper airway RV detection was associated with relapsed hematologic malignancies, higher level of C-reactive protein, and prior use of high dose steroids and anti-cancer chemotherapeutic drugs. Furthermore, it was independently associated with in-hospital mortality (adjusted odds ratio, 2.36; 95% confidence interval, 1.23 to 4.54). Among different RVs, parainfluenza virus was more prevalent among patients who died in the hospital than among those who survived (11.5% vs. 3.5%, P = 0.027).

Conclusions

RV detection in the upper respiratory tract was relatively common in our cohort and was significantly associated with a poor prognosis. Thus, it can be used as a predictor of prognosis. Moreover, RV presence in the upper respiratory tract should be examined in patients who have previously been prescribed with high dose corticosteroids and anti-cancer drugs.

The Impact of NLRP3 Activation on Hematopoietic Stem Cell Transplantation

NLR family pyrin domain-containing 3 (NLRP3) is an intracellular protein that after recognizing a broad spectrum of stressors, such as microbial motifs and endogenous danger signals, promotes the activation and release of the pro-inflammatory cytokines IL-1β and IL-18, thus playing an essential role in the innate immune response. Several blood cell types, including macrophages, dendritic cells, and hematopoietic stem and progenitor cells (HSPCs), express NLRP3, where it has been implicated in various physiological and pathological processes. For example, NLRP3 participates in the development and expansion of HSPCs, and their release from bone marrow into the peripheral blood has been implicated in certain hematological disorders including various types of leukemia. In addition, accumulating evidence indicates that activation of NLRP3 plays a pivotal role in the development of transplant complications in patients receiving hematopoietic stem cell transplantation (HSCT) including graft versus host disease, severe infections, and transplant-related mortality. The majority of these complications are triggered by the severe tissue damage derived from the conditioning regimens utilized in HSCT which, in turn, activates NLRP3 and, ultimately, promotes the release of proinflammatory cytokines such as IL-1β and IL-18. Here, we summarize the implications of NLRP3 in HSCT with an emphasis on the involvement of this inflammasome component in transplant complications.

MiR-181a and -b expression in acute lymphoblastic leukemia and its correlation with acute graft-versus-host disease after hematopoietic stem cell transplantation, COVID-19 and torque teno viruses

Acute lymphoblastic leukemia (ALL), a malignant transformation and proliferation of the lymphoid line of blood cells, is characterized by chromosomal abnormalities and genetic changes. The purpose of this research was the evaluation of expression level of miR-181a and -b in patients with ALL compared to the control group. Furthermore, we examined their expression level in hematopoietic stem-cell transplantation (HSCT) patients who developed acute graft-versus-host disease (aGVHD) in comparison with those without aGVHD and explore the relationship between their expression level and cytogenetic abnormalities. In this cross-sectional study, 76 newly diagnosed adult De novo ALL patients were enrolled who were admitted to our referral hospital. All patients received standard chemotherapy, consisting of daunorubicin. A total of 37 patients underwent HSCT from the related human leukocyte antigen-matched donors. ALL patients have been diagnosed with the coronavirus disease 2019 (COVID-19) and Torque teno viruses (TTVs). We assessed the expression levels of miR-181a and -b in the peripheral blood sample of ALL patients at the time of diagnosis prior to chemotherapy, and healthy matched individuals by RT–PCR. TTVs and COVID-19 load were also determined via RT–PCR. In conclusion, the expression level of miR-181a and -b were significantly higher in ALL patients than healthy controls and also increased in patients who developed aGVHD in comparison with those without aGVHD. MiR-181a and -b can be a useful biomarker in ALL and a useful indicator of aGVHD. The expression level of miR-181a in ALL patients with COVID-19 is significantly up-regulated, while it is reduced in these patients with TTV.

Is it time to reconsider prophylactic antimicrobial use for hematopoietic stem cell transplantation? a narrative review of antimicrobials in stem cell transplantation

INTRODUCTION

Hematopoietic Stem Cell Transplantation (HSCT) is a life-saving procedure for multiple types of hematological cancer, autoimmune diseases, and genetic-linked metabolic diseases in humans. Recipients of HSCT transplant are at high risk of microbial infections that significantly correlate with the presence of graft-versus-host disease (GVHD) and the degree of immunosuppression. Infection in HSCT patients is a leading cause of life-threatening complications and mortality.

AREAS COVERED

This review covers issues pertinent to infection in the HSCT patient, including bacterial and viral infection; strategies to reduce GVHD; infection patterns; resistance and treatment options; adverse drug reactions to antimicrobials, problems of antimicrobial resistance; perturbation of the microbiome; the role of prebiotics, probiotics, and antimicrobial peptides. We highlight potential strategies to minimize the use of antimicrobials.

EXPERT OPINION

Measures to control infection and its transmission remain significant HSCT management policy and planning issues. Transplant centers need to consider carefully prophylactic use of antimicrobials for neutropenic patients. The judicious use of appropriate antimicrobials remains a crucial part of the treatment protocol. However, antimicrobials' adverse effects cause microbiome diversity and dysbiosis and have been shown to increase morbidity and mortality.

Clinical risk score for predicting invasive fungal disease after allogeneic hematopoietic stem cell transplantation: Analysis of the China Assessment of Antifungal Therapy in Hematological Diseases (CAESAR) study

BACKGROUND AND OBJECTIVE

Invasive fungal disease (IFD) is associated with a high mortality for patients with hematological malignancies undergoing allogeneic hematopoietic stem cell transplantation (allo-HSCT). This study aimed not only to develop a proven/probable IFD risk-scoring model but to identify high-risk populations that would benefit from anti-fungal prophylaxis.

METHODS

Data from the China Assessment of Antifungal Therapy in Hematological Diseases (CAESAR) study were retrieved, and all patients (n = 1053) undergoing allo-HSCT were randomly divided into the training set (n = 685) for model development and the validation set (n = 368) for model verification. A weighted risk score for proven or probable IFD was established through multivariate logistic regression analysis.

RESULTS

The study population had a mean age of 28.95 years and the majority underwent myeloablative transplantation in complete remission 1 (53.4%). Five risk factors of IFD were identified, namely neutropenia lasting longer than 14 days, corticosteroid use, diabetes, haploidentical donor, and unrelated donor. Based on the risk score for IFD, the patients were categorized into three groups: low risk (score 0-4, 1.5%-4.0%), intermediate risk (score 5-8, 9.8%), and high risk (score>8, 24.7%-14.0%). Anti-fungal prophylaxis may provide benefits for patients with intermediate (8.5% vs. 18.5%, P = .0085) or high risk (19.4% vs. 30.8%, P = .4651) but not low risk (2.1% vs. 3.8%, P = .6136) of IFD.

CONCLUSION

A practical weighted risk score for IFD in patients receiving allo-HSCT was established, which can aid decision-making regarding the administration of anti-fungal prophylaxis.

Predictors of a short hospitalization in bone marrow transplantation patients presenting to the emergency department

BACKGROUND

Despite the advantages of bone marrow transplantation (BMT), patients receiving this intervention visit the emergency department (ED) frequently and for various reasons. Many of those ED visits result in hospitalization, and the length of stay varies.

OBJECTIVES

The objective of our study was to identify the patients who were only briefly hospitalized and were thus eligible for safe discharge from the ED.

METHODS

This was a retrospective cohort study conducted on all adult patients who have completed a successful BMT and had an ED visit that resulted in hospitalization.

RESULTS

Our study included 115 unique BMT with a total number of 357 ED visits. Around half of those visits resulted in a short hospitalization. We found higher odds of a short hospitalization among those who have undergone autologous BMT (95%CI [1.14-2.65]). Analysis of the discharge diagnoses showed that patients with gastroenteritis were more likely to have a shorter hospitalization in comparison to those diagnosed with others (95%CI [1.10-3.81]). Furthermore, we showed that patients who presented after a month from their procedure were more likely to have a short hospitalization (95%CI [1.04-4.87]). Another significant predictor of a short of hospitalization was the absence of Graft versus Host Disease (GvHD) (95%CI [2.53-12.28]). Additionally, patients with normal and high systolic blood pressure (95%CI [2.22-6.73] and 95%CI [2.81-13.05]; respectively), normal respiratory rate (95%CI [2.79-10.17]) and temperature (95%CI [2.91-7.44]) were more likely to have a shorter hospitalization, compared to those presenting with abnormal vitals. Likewise, we proved higher odds of a short hospitalization in patients with a quick Sepsis Related Organ Failure Assessment score of 1-2 (95%CI [1.29-5.20]). Moreover, we demonstrated higher odds of a short hospitalization in patients with a normal platelet count (95%CI [1.39-3.36]) and creatinine level (95%CI [1.30-6.18]).

CONCLUSION

In our study, we have shown that BMT patients visit the ED frequently and many of those visits result in a short hospitalization. Our study showed that patients presenting with fever/chills are less likely to have a short hospitalization. We also showed a significant association between a short hospitalization and BMT patients without GvHD, with normal RR, normal T °C and a normal platelet count.

Trained Immunity-Based Vaccine in B Cell Hematological Malignancies With Recurrent Infections: A New Therapeutic Approach

Infectious complications are a major cause of morbidity and mortality in B-cell hematological malignancies (HM). Prophylaxis for recurrent infections in HM patients with antibody deficiency consists of first-line antibiotics and when unsuccessful, gammaglobulin replacement therapy (IgRT). Recent knowledge of trained immunity-based vaccines (TIbV), such as the sublingual polybacterial formulation MV130, has shown a promising strategy in the management of patients with recurrent infections. We sought to determine the clinical benefit of MV130 in a cohort of HM patients with recurrent respiratory tract infections (RRTIs) who underwent immunization with MV130 for 3 months. Clinical information included the frequency of infections, antibiotic use, number of visits to the GP and hospitalizations previous and after MV130 immunotherapy. Improvement on infection rate was classified as: clear (>60% reduction of infection), partial (26%-60%) and low (≤25%) improvement. Fifteen HM patients (aged 42 to 80 years; nine females) were included in the study. All patients reduced their infection rate. Analysis of paired data revealed that the median (range, min - max) of respiratory infectious rate significantly decreased from 4.0 (8.0-3.0) to 2.0 (4.0-0.0) (p<0.001) at 12 months of MV130. A clear clinical improvement was observed in 53% (n = 8) of patients, partial improvement in 40% (n = 6) and low improvement in 7% (n = 1). These data correlated with a decrease on antibiotic consumption from 3.0 (8.0-1.0) to 1.0 (2.0-0.0) (p = 0.002) during 12 months after initiation of treatment with MV130. The number of infectious-related GP or emergency room visits declined from 4.0 (8.0-2.0) to 2.0 (3.0-0.0) (p<0.001), in parallel with a reduction in hospital admissions due to infections (p = 0.032). Regarding safety, no adverse events were observed. On the other hand, immunological assessment of serum IgA and IgG levels demonstrated an increase in specific antibodies to MV130-contained bacteria following MV130 immunotherapy. In conclusion, MV130 may add clinical benefit reducing the rate of infections and enhancing humoral immune responses in these vulnerable patients.

Oral shedding of CMV and HSV-1 in hematopoietic stem cell transplantation patients

OBJECTIVES

To evaluate the oral shedding of herpesviruses in patients undergoing hematopoietic stem cell transplantation (HSCT) and correlate it with oral mucositis (OM).

METHODS

Saliva samples were collected before the HSCT and on day D + 8. Multiplex Polymerse Chain Reaction (PCR) was performed to detect herpes simplex virus (HSV)-1 and HSV-2, Epstein-Barr virus (EBV), Cytomegalovirus (CMV), Variella-zoster virus (VZV), and human herpesvirus (HHV)-6, HHV-7, and HHV-8. OM was assessed according to WHO criteria.

RESULTS

Thirty one patients were enrolled, in which 20 of 31 (64.5%) were males; median age was 50 (21-70) years; 16 of 31 (51.6%) underwent allo-HSCT; and 15 of 31 (48.4%) underwent auto-HSCT. On D + 8, OM grades III and IV were observed in 8 of 31 (25.8%) patients. In the first salivary collection, EBV was found in 24 of 31 (77.4%), followed by HHV-6 (7/31, 22.6%) and HHV-7 (8/31 25.8%). In the second collection, EBV was found in 24 of 27(89%), followed by HSV-1 (8/27, 30%) and CMV, HHV-6, and HHV-7 (5/27, 18.5%, each one). On D + 8, OM grades II and IV were associated with the presence of HSV-1. HSV-1 was also associated with worsening degrees of OM on D + 15.

CONCLUSION

The presence of HSV-1 and CMV in oral samples was more frequent on day D + 8 after HSCT. HSV-1 detection was associated with severity and worsening of OM. HSV-1 and CMV seem to be associated with oral dysbiosis due to HSCT.

Evaluation of pulmonary complications in patients undergoing allogenic stem cell transplantation

Background

Mature blood cells can be differentiated from hematopoietic stem cells; thus, the latter can play a crucial role in maintaining defense against different microorganisms. Thus, hematopoietic stem cell transplantation is one of the most important lines of immunotherapy. Major systemic complications may occur post transplantation and could be fatal. Pulmonary complications include infectious and non-infectious complications. The aim of this study was to detect the pulmonary complications in allogeneic stem cell transplantation patients.

Results

We studied 20 patients after transplantation of allogeneic stem cells with regular follow-up in outpatient clinic of hematology department of Alexandria Main University Hospital. All the studied patients were subjected to history taking, plain x-ray chest PA view, CT chest, complete blood count, serum creatinine, liver enzymes, and serum cytomegalovirus (CMV) detection by antibodies IgG and IgM. Regarding sputum sampling, 7 patients’ samples (35%) were obtained either spontaneously or by induction via hypertonic saline 3%. One patient (5%) had miniBAL done, while bronchoalveolar lavage using fiber optic bronchoscopy was done for 2 patients (10%). Samples could not be obtained from the remaining patients. Samples were analyzed for culture for bacteria, Pneumocystis jiroveci using immunofluorescence test, CMV PCR, fungal culture, and smear for acid fast bacilli (AFB). Among the examined patients, 2 patients (20%) had pulmonary bacterial infection including streptococcus and multidrug-resistant strain of Klebsiella, 3 patients (30%) had pulmonary candida infection, and one patient (10%) had positive result of pulmonary CMV of low count which was considered insignificant. None of our patients had positive results for pulmonary tuberculosis nor Pneumocystis jiroveci. Six patients (30%) had CMV in serum; 3 patients (15.8%) had manifested CMV reactivation. One patient (5%) of our patients had pulmonary graft versus host disease GVHD. One patient (5%) had died during our study course within 12 days post-transplantation due to ARDS followed by multiple organ failure.

Conclusion

The prevalence of pulmonary infectious complications after allogenic stem cell transplantation was 50% of all studied patients, while 5% of the studied patients presented with non-infectious pulmonary complications.

Viral Respiratory Infections in Hematological Patients

Viral infections of the respiratory system represent one of the most important complications in hematological patients in terms of both the severity of the clinical picture and its related impact on the duration of hospitalization, and of mortality. The most implicated viruses are those that commonly cause community-based respiratory diseases: respiratory syncytial virus, Influenza virus and rhinovirus. However, in some cases the clinical picture may be triggered by first infection with or reactivation of pathogens normally not responsible for clinically relevant diseases in immunocompetent subjects. This issue is currently being taken into greater consideration within the scientific community. However, the strong heterogeneity in the epidemiology and clinical expression of these infections and the lack of adequate therapeutic options imply that there is currently no uniform consensus on the best management of these patients. The main purpose of this review is to highlight which viruses are currently most implicated in the onset of these infections, what is their incidence in so heterogeneous and fragile patients and the factors that lead to disease's onset and evolution. Possible or available clinical management options, diagnostic and therapeutic tools, and preventive and prophylaxis measures are also discussed.

Cytokine Storm in COVID-19-Immunopathological Mechanisms, Clinical Considerations, and Therapeutic Approaches: The REPROGRAM Consortium Position Paper

Cytokine storm is an acute hyperinflammatory response that may be responsible for critical illness in many conditions including viral infections, cancer, sepsis, and multi-organ failure. The phenomenon has been implicated in critically ill patients infected with SARS-CoV-2, the novel coronavirus implicated in COVID-19. Critically ill COVID-19 patients experiencing cytokine storm are believed to have a worse prognosis and increased fatality rate. In SARS-CoV-2 infected patients, cytokine storm appears important to the pathogenesis of several severe manifestations of COVID-19: acute respiratory distress syndrome, thromboembolic diseases such as acute ischemic strokes caused by large vessel occlusion and myocardial infarction, encephalitis, acute kidney injury, and vasculitis (Kawasaki-like syndrome in children and renal vasculitis in adult). Understanding the pathogenesis of cytokine storm will help unravel not only risk factors for the condition but also therapeutic strategies to modulate the immune response and deliver improved outcomes in COVID-19 patients at high risk for severe disease. In this article, we present an overview of the cytokine storm and its implications in COVID-19 settings and identify potential pathways or biomarkers that could be targeted for therapy. Leveraging expert opinion, emerging evidence, and a case-based approach, this position paper provides critical insights on cytokine storm from both a prognostic and therapeutic standpoint.

Prospective evaluation of clinical symptoms of chemotherapy-induced oral mucositis in adult patients with acute leukemia: A preliminary study

OBJECTIVE

The objective of this study was to prospectively evaluate the clinical features of chemotherapy-induced oral mucositis (CIOM) in adult patients with acute leukemia and the aggravating factors for such symptoms.

SUBJECTS

Thirty-seven prospective patients aged ≥19 years with acute leukemia undergoing chemotherapy were enrolled. Oral and clinical investigations were performed at baseline and on Day 14 after starting chemotherapy. The presence and severity of cancer-induced oral mucositis were demonstrated using the World Health Organization (WHO) scoring system.

RESULTS

On Day 14, we found that oral mucositis had developed in eight patients (21.6%). Hematopoietic stem cell transplantation (HSCT) in patients was a predictor of increased WHO scores (β = 1.937, p < .001). Regarding oral sites, ventral tongue (β = 1.670), soft palate (β = 1.242), and buccal mucosa (β = 0.593) were predictors for increased scores. In addition, the increase in WHO scores was positively correlated with the number of oral lesions (r = .521), the difficulty in eating (r = .250), and the overall oral health (r = .534; all p < .05).

CONCLUSION

The main factors affecting the severity of CIOM symptoms were the treatment with HSCT and the location of oral lesions. The incidence of CIOM and WHO scores were not significantly different between the subgroups of disease. Our findings will help clinicians investigate the oral findings after chemotherapy in adult patients with acute leukemia.

Respiratory Viruses Cause Late Morbidity in Recipients of Hematopoietic Stem Cell Transplantation

Common respiratory viral infections (CRVIs) frequently complicate hematopoietic stem cell transplantation (HSCT). We conducted a retrospective, single-center, observational cohort study to determine the incidence of CRVI in patients who received an allogeneic (allo) or autologous (auto) HSCT at the Royal Adelaide Hospital between 2009 and 2017. The median follow-up was 8.9 and 4.5 years for auto- and allo-HSCT recipients, respectively. There were 149 CRVI episodes in 74 patients, with rhinovirus being the most commonly isolated virus (n = 81, 47%). The majority of CRVIs (113/149, 75.8%) occurred more than 100 days post-HSCT and 67% were diagnosed in the outpatient setting. There was evidence of lower respiratory tract infection (LRTI) in 45.6% (68/149) of CRVIs. On multivariate logistic regression analysis, coviral infections and cytomegalovirus viremia were independent risk factors for progression of CRVI to LRTI. Ten (6.7%) CRVI episodes resulted in admission to intensive care for ventilatory support and 8 (5.4%) patients died within 30 days of CRVI diagnosis. In our study, 10.4% of HSCT recipients experienced a CRVI post-transplant, primarily causing late morbidity and potentially mortality. Prevention with strict infection control practices, vaccination, and patient education is essential.

Characteristics and risk factors for mortality of invasive non-Aspergillus mould infections in patients with haematologic diseases: A single-centre 7-year cohort study

Since mould-active azole prophylaxis has become a standard approach for patients with high-risk haematologic diseases, the epidemiology of invasive fungal infections (IFIs) has shifted towards non-Aspergillus moulds. It was aimed to identify the epidemiology and characteristics of non-Aspergillus invasive mould infections (NAIMIs). Proven/probable NAIMIs developed in patients with haematologic diseases were reviewed from January 2011 to August 2018 at Catholic Hematology hospital, Seoul, Korea. There were 689 patients with proven/probable invasive mould infections; of them, 46 (47 isolates) were diagnosed with NAIMIs. Fungi of the Mucorales order (n = 27, 57.4%) were the most common causative fungi, followed by Fusarium (n = 9, 19.1%). Thirty-four patients (73.9%) had neutropenia upon diagnosis of NAIMIs, and 13 (28.3%) were allogeneic stem cell transplantation recipients. The most common site of NAIMIs was the lung (n = 27, 58.7%), followed by disseminated infections (n = 8, 17.4%). There were 23.9% (n = 11) breakthrough IFIs, and 73.9% (n = 34) had co-existing bacterial or viral infections. The overall mortality at 6 and 12 weeks was 30.4% and 39.1%, respectively. Breakthrough IFIs (adjusted hazards ratio [aHR] = 1.99, 95% CI: 1.3-4.41, P = .031) and surgical treatment (aHR = 0.09, 95% CI: 0.02-0.45, P = .003) were independently associated with 6-week overall mortality. NAIMIs were not rare and occur as a complex form of infection often accompanied by breakthrough/mixed/concurrent IFIs and bacterial or viral infections. More active diagnostic efforts for NAIMIs are needed.

Sustained Delivery System for Stem Cell-Derived Exosomes

Recent literature has ascribed that the paracrine action of stem cells is mediated by exosomes. Exosomes are nano-sized extracellular vesicles (30 to 100 nm) of endocytic origin that play important roles in intercellular communication. They have the ability to deliver various therapeutic effects, e.g., skin regeneration or cardiac function recovery, when applied topically or injected systemically. However, injection of exosomes has been shown to result in rapid clearance from blood circulation and accumulation of the exosomes in the liver, spleen, lung, and gastrointestinal tract can be found as early as 2 h after injection. Topical administration of exosomes on the skin or ocular surface would suffer the same fate due to rapid fluid turnover (sweat or tears). Biodegradable or highly porous hydrogels have been utilized to load exosomes and to deliver a sustained therapeutic effect. They can also prevent the exosomes from being cleared prematurely and allow the delivery of a more localized and concentrated exosome dosage by placing the hydrogel directly at or in the proximity of the target site. In this mini-review, we elaborate on the challenges of conventional exosome administration and highlight the solution to the shortcomings in the form of exosome-incorporated hydrogels. Different techniques to encapsulate exosomes and examples of hydrogels that have been used to create sustained delivery systems of exosomes are also discussed.

Reactivation and dynamics of cytomegalovirus and Epstein-Barr virus after rabbit antithymocyte globulin and cyclosporine for aplastic anemia

OBJECTIVES

This study aimed to identify the natural course of cytomegalovirus (CMV)/Epstein-Barr virus (EBV) after rabbit antithymocyte globulin and cyclosporine (rATG-CsA) for aplastic anemia (AA).

METHODS

In 113 prospectively observed AA patients treated with rATG-CsA, the CMV/EBV cohort was classified into two groups by baseline viremic status: no viremia (CMV-G1, n = 112; EBV-G1, n = 98) and the presence of viremia (CMV-G2, n = 1; EBV-G2, n = 13).

RESULTS

In CMV-G1, the mean CMV load increased up to 3 months but was completely resolved from 6 months. The mean EBV load of EBV-G1 showed a peak at 1 month and then gradually decreased over time but remained detectable throughout the observation period. EBV-G2 showed fluctuating EBV dynamics. With reactivation rates of 38.4% in CMV-G1 and 62.2% in EBV-G1, a longer time to rATG-CsA from diagnosis and a lower absolute lymphocyte count at 1 month from rATG-CsA were significantly associated with CMV and EBV reactivation, respectively. The mean peak CMV and EBV loads of patients with CMV-related (3.5%) and EBV-related (0.9%) diseases were evidently higher than those of the remaining patients without CMV and EBV diseases in the respective cohort.

CONCLUSION

Considering frequent reactivation and distinct courses of CMV/EBV, virologic surveillance is recommended after rATG-CsA for AA.

Cytomegalovirus Infections after Hematopoietic Stem Cell Transplantation: Current Status and Future Immunotherapy

Cytomegalovirus (CMV) infection after hematopoietic stem cell transplantation (HSCT) is one of the critical infectious complications related to host immune recovery. The spectrum of CMV infection is quite extensive, from asymptomatic CMV reactivation presenting mainly as CMV DNAemia to fatal CMV diseases involving gut, liver, lungs, or brain. In addition to organ involvement, CMV reactivation can exert indirect effects such as immunosuppression or graft failure that may result in the development of concurrent infectious complications. Currently, preemptive therapy, which is based on PCR-based monitoring of CMV from blood, is a mainstay enabling improvement in CMV-related outcomes. During the past decades, new antiviral drugs, clinical trials for prophylaxis in high-risk groups, and vaccines for preventing CMV infection have been introduced. In addition, data for immunologic monitoring and adoptive immunotherapy have also been accumulated. Here, we review the current status and recent updates in this field, with future perspectives including immunotherapy in HSCT recipients.

Pretransplant C-reactive protein as a prognostic marker in allogeneic stem cell transplantation: A PRISMA-compliant meta-analysis

BACKGROUND

Numerous reports have explored the prognostic value of pretransplant serum C-reactive protein (CRP) in patients receiving allogeneic stem cell transplant (ASCT), but the results remain conflicting. Therefore, we performed a meta-analysis to comprehensively assess the prognostic value of pretransplant serum CRP in patients receiving ASCT.

METHODS

We systematically searched eligible studies in PubMed, Embase, and Web of Science from 1999 to September 2018. The pooled hazard ratios (HRs) and their corresponding 95% CIs were used to synthetically assess the prognostic value of pre-ASCT CRP in terms of overall survival (OS), non-relapse mortality (NRM), and acute graft versus host disease (aGVHD).

RESULTS

A total of 14 articles with 15 studies containing 3458 patients were included in this meta-analysis. The pooled results showed that high pre-ASCT CRP level was significantly related to worse OS (HR = 1.63; 95% CI: 1.34-1.98; P < .05), to an increased risk of NRM (HR = 2.06; 95% CI: 1.62-2.62; P < .05), and aGVHD (HR = 1.35; 95% CI: 1.07-1.71; P < .05). Additionally, sensitivity and subgroup analyses demonstrated that our pooled results were stable and reliable.

CONCLUSIONS

High pre-ASCT serum CRP was significantly associated with worse OS, as well as higher risk of NRM and aGVHD. CRP may be a candidate factor of updating the existing risk scoring systems or establishing a novel risk scoring systems, which has the potential of guiding patient selection for ASCT and proceeding with risk-adapted therapeutic strategies. However, more high-quality clinical studies and basic research are required to further validate our findings in view of several limitations in our meta-analysis.

Infection Complications in Hematopoietic Stem Cells Transplant Recipients: Do Genetics Really Matter?

Hematopoietic stem cell transplantation (HSCT) is a highly advanced technique that offers a potential cure for an increasing number of life-threatening diseases. Enormous progress achieved in the last decade, including the refinement of donor selection and advancements in patient supportive care, had significantly improved transplant outcomes; however, invasive infections, graft-vs.-host disease (GVHD) and other serious complications still represent a major source of morbidity and mortality in HSCT recipients. The damage of anatomical barriers due to pre-transplant conditioning, a severely damaged immune function and a profound disruption in the composition of gut microbial commensals (gut microbiota) are alterations inherent to the transplant procedure that are directly implicated in the development of invasive infections and other HSCT complications. Although HLA-matching represents the most important genetic predictor of transplant outcomes, genetic variants in non-HLA genes, especially single nucleotide polymorphisms (SNPs) of genes encoding proteins associated with the immune response to tissue injury and pathogen infection have also been proposed as additional risk factors implicated in the occurrence of HSCT complications. Furthermore, although the microbiota composition is affected by several factors, recent evidence suggests that certain host genetic variants are associated with an altered composition of the gut microbiome and may, therefore, predispose some individuals to invasive infectious complications. This article summarizes the current understanding of the influence that genetic variants in non-HLA genes have on the development of infectious complications in HSCT recipients.

Implementation of Hospital Policy for Healthcare Workers and Patients Exposed to Varicella-Zoster Virus

Varicella-zoster virus (VZV) causes a highly contagious and generally benign, self-limited disease. However, in high-risk populations including immunocompromised patients, pregnant women, and neonates, VZV infection can be associated with significant morbidity and mortality. Healthcare-associated transmission of VZV occurs among healthcare workers (HCWs) and patients by airborne transmission or by direct contact with the index case. To minimize the risk of transmission in healthcare settings, all VZV-susceptible HCWs should be encouraged strongly to be immunized with the varicella vaccine. For post-exposure management, active immunization (varicella vaccine), passive immunization (varicella-zoster immune globulin) and/or antiviral agents, and isolation could be used in specific situations. To prevent the transmission of VZV infection in the hospital settings, the development and implementation of hospital policies for appropriate infection control is also warranted. This article reviews the general information and healthcare-associated transmission of VZV and summarizes the recommendations for the pre- and post-exposure management of HCWs and patients, in hospital settings.