H1N1 infection in a cohort of hematopoietic stem cell transplant recipients: prompt antiviral therapy might be life saving

Risk factors for lower respiratory tract disease and outcomes in allogeneic hematopoietic stem cell transplantation recipients with influenza virus infection

INTRODUCTION

Influenza virus infection (IVI) is frequent in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients, and reports from several countries indicate high morbidity and mortality from progression to lower respiratory tract disease (LRTD). However, there have been no reports on IVI clinical characteristics, treatment outcomes, and risk factor for progression to LRTD among allo-HSCT recipients in Japan.

METHODS

We retrospectively reviewed the medical charts of allo-HSCT recipients who developed IVI between 2012 and 2019.

RESULTS

Forty-eight cases of IVI following allo-HSCT were identified at our institution. The median age was 42 years, and median time from allo-HSCT to IVI was 25 months. Thirty-seven patients (77.1%) were administered neuraminidase inhibitors (NAIs) as antiviral therapy within 48 h of symptom onset (early therapy), whereas 11 (22.9%) received NAI over 48 h after onset (delayed therapy). Subsequently, 12 patients (25.0%) developed LRTD after IVI. Multivariate analysis identified older age (hazard ratio [HR], 7.65; 95% confidence interval [CI], 2.22-26.3) and bronchiolitis obliterans (HR, 5.74; 95% CI, 1.57-21.0) as independent risk factors for progression to LRTD. Moreover, land-mark analysis showed that early therapy prevented progression to LRTD (11.8% vs. 45.5%, P = 0.013). The IVI-related mortality rate was 2.1%.

CONCLUSIONS

Early NAI treatment is recommended for reducing the risk of LRTD progression due to IVI in allo-HSTC recipients, particularly for older patients and those with bronchiolitis obliterans.

Impact of Influenza Infection Among Adult and Pediatric Populations With Hematologic Malignancy and Hematopoietic Stem Cell Transplant: A Systematic Review and Meta-Analysis

PURPOSE

Influenza is increasingly recognized as a leading cause of morbidity and mortality in patients with hematologic malignancies and recipients of hematopoietic stem cell transplantation (HSCT). However, the impact of influenza on this population has not been previously evaluated in a systematic review. This study systematically reviewed and summarized the outcomes of influenza infection as to in-hospital influenza-related mortality, development of lower respiratory tract infection and acute respiratory distress syndrome, need for hospitalization, intensive care unit admission, and mechanical ventilation.

METHODS

We conducted a systematic search of literature using the PubMed and EMBASE databases for articles published from January 1989 through January 19, 2020, reporting laboratory-confirmed influenza in patients of any age with hematologic malignancies and HSCT. Time from transplantation was not included in the search criteria. The impact of antiviral therapy on influenza outcomes was not assessed due to heterogeneity in antiviral treatment provision across the studies. Patients with influenza-like illness, solid-tumor cancers, or nonmalignant hematologic diseases were excluded from the study. A random-effects meta-analysis was performed to estimate the prevalences and 95% CIs of each outcome of interest. A subgroup analysis was carried out to assess possible sources of heterogeneity and to evaluate the potential impact of age on the influenza infection outcomes. Heterogeneity was assessed using the I² statistic.

FINDINGS

Data from 52 studies providing data on 1787 patients were included in this analysis. During seasonal epidemics, influenza-related in-hospital mortality was 16.60% (95% CI, 7.49%-27.7%), with a significantly higher death rate in adults compared to pediatric patients (19.55% [95% CI, 10.59%-29.97%] vs 0.96% [95% CI, 0%-6.77%]; P < 0.001). Complications from influenza, such as lower respiratory tract infection, developed in 35.44% of patients with hematologic malignancies and HSCT recipients, with a statistically significant difference between adults and children (46.14% vs 19.92%; P < 0.001). However, infection resulted in a higher hospital admission rate in pediatric patients compared to adults (61.62% vs 22.48%; P < 0.001). For the 2009 H1N1 pandemic, no statistically significant differences were found between adult and pediatric patients when comparing the rates of influenza-related in-hospital mortality, lower respiratory tract infection, and hospital admission. Similarly, no significant differences were noted in any of the outcomes of interest when comparing H1N1 pandemic with seasonal epidemics.

IMPLICATIONS

Regardless of influenza season, patients, and especially adults, with underlying hematologic malignancies and HSCT recipients with influenza are at risk for severe outcomes including lower respiratory tract infection and in-hospital mortality.

Respiratory Virus Infections in Hematopoietic Cell Transplant Recipients

Highly immunocompromised pediatric and adult hematopoietic cell transplant (HCT) recipients frequently experience respiratory infections caused by viruses that are less virulent in immunocompetent individuals. Most of these infections, with the exception of rhinovirus as well as adenovirus and parainfluenza virus in tropical areas, are seasonal variable and occur before and after HCT. Infectious disease management includes sampling of respiratory specimens from nasopharyngeal washes or swabs as well as sputum and tracheal or tracheobronchial lavages. These are subjected to improved diagnostic tools including multiplex PCR assays that are routinely used allowing for expedient detection of all respiratory viruses. Disease progression along with high mortality is frequently associated with respiratory syncytial virus, parainfluenza virus, influenza virus, and metapneumovirus infections. In this review, we discuss clinical findings and the appropriate use of diagnostic measures. Additionally, we also discuss treatment options and suggest new drug formulations that might prove useful in treating respiratory viral infections. Finally, we shed light on the role of the state of immune reconstitution and on the use of immunosuppressive drugs on the outcome of infection.

Respiratory viruses in transplant recipients: more than just a cold. Clinical syndromes and infection prevention principles

OBJECTIVES

The aim of this review is to provide updated information on the clinical spectrum, treatment options, and infection prevention strategies for respiratory viral infections (RVIs) in both solid organ (SOT) and hematopoietic stem cell transplant (HSCT) patients.

METHODS

The MEDLINE and PubMed databases were searched for literature regarding the aforementioned aspects of RVIs, with focus on respiratory syncytial virus, adenovirus, influenza virus, parainfluenza virus, human metapneumovirus, and rhinovirus.

RESULTS

Compared to immunocompetent hosts, SOT and HSCT patients are much more likely to experience a prolonged duration of illness, prolonged shedding, and progression of upper respiratory tract disease to pneumonia when infected with respiratory viruses. Adenovirus and respiratory syncytial virus tend to have the highest mortality and risk for disseminated disease, but all the RVIs are associated with higher morbidity and mortality in these patients than in the general population. These viruses are spread via direct contact and aerosolized droplets, and nosocomial spread has been reported.

CONCLUSIONS

RVIs are associated with high morbidity and mortality among SOT and HSCT recipients. Management options are currently limited or lack strong clinical evidence. As community and nosocomial spread has been reported for all reviewed RVIs, strict adherence to infection control measures is key to preventing outbreaks.

A pilot randomized trial of adjuvanted influenza vaccine in adult allogeneic hematopoietic stem cell transplant recipients

The annual influenza vaccine is recommended for hematopoietic stem cell transplant (HSCT) patients although studies have shown suboptimal immunogenicity. Influenza vaccine containing an oil-in-water emulsion adjuvant (MF59) may lead to greater immunogenicity in HSCT recipients. We randomized adult allogeneic HSCT patients to receive the 2015-2016 influenza vaccine with or without MF59 adjuvant. Preimmunization and 4-week post-immunization sera underwent strain-specific hemagglutination inhibition assay. We randomized 73 patients and 67 (35 adjuvanted; 32 non-adjuvanted) had paired samples available at follow-up. Median age was 54 years (range 22-74) and time from transplant was 380 days (range 85-8107). Concurrent graft-versus-host disease was seen in 42/73 (57.5%). Geometric mean titers increased significantly after vaccination in both groups. Seroconversion to at least one of three influenza antigens was present in 62.9% vs 53.1% in adjuvanted vs non-adjuvanted vaccine (P=0.42). Factors associated with lower seroconversion rates were use of calcineurin inhibitors (P<0.001) and shorter duration from transplantation (P=0.001). Seroconversion rates were greater in patients who got previous year influenza vaccination (82.6% vs 45.5%, P=0.03). Adjuvanted vaccine demonstrated similar immunogenicity to non-adjuvanted vaccine in the HSCT population and may be an option for some patients.

Pandemic 2009 Influenza A (H1N1) virus infection in cancer and hematopoietic stem cell transplant recipients; a multicenter observational study

BACKGROUND

During March 2009 a novel Influenza A virus emerged in Mexico. We describe the clinical picture of the pandemic Influenza A (H1N1) Influenza in cancer patients during the 2009 influenza season.

METHODS

Twelve centers participated in a multicenter retrospective observational study of cancer patients with confirmed infection with the 2009 H1N1 Influenza A virus (influenza-like illness or pneumonia plus positive PCR for the 2009 H1N1 Influenza A virus  in respiratory secretions). Clinical data were obtained by retrospective chart review and analyzed. 

RESULTS

From May to August 2009, data of 65 patients were collected. Median age was 51 years, 57 % of the patients were female. Most patients (47) had onco-hematological cancers and 18 had solid tumors. Cancer treatment mainly consisted of chemotherapy (46), or stem cell transplantation (SCT) (16). Only 19 of 64 patients had received the 2009 seasonal Influenza vaccine. Clinical presentation included pneumonia (43) and upper respiratory tract infection (22). Forty five of 58 ambulatory patients were admitted. Mechanical ventilation was required in 12 patients (18%). Treatment included oseltamivir monotherapy or in combination with amantadine for a median of 7 days. The global 30-day mortality rate was 18%. All 12 deaths were among the non-vaccinated patients. No deaths were observed among the 19 vaccinated patients. Oxygen saturation <96% at presentation was a predictor of mortality (OR 19.5; 95%CI: 2.28 to 165.9).

CONCLUSIONS

In our cancer patient population, the pandemic 2009 Influenza A (H1N1) virus was associated with high incidence of pneumonia (66%), and 30-day mortality (18.5%). Saturation <96% was significantly associated with death. No deaths were observed among vaccinated patients.

Pandemic 2009 Influenza A (H1N1) virus infection in cancer and hematopoietic stem cell transplant recipients; a multicenter observational study

BACKGROUND

During March 2009 a novel Influenza A virus emerged in Mexico. We describe the clinical picture of the pandemic Influenza A (H1N1) Influenza in cancer patients during the 2009 influenza season.

METHODS

Twelve centers participated in a multicenter retrospective observational study of cancer patients with confirmed infection with the 2009 H1N1 Influenza A virus (influenza-like illness or pneumonia plus positive PCR for the 2009 H1N1 Influenza A virus  in respiratory secretions). Clinical data were obtained by retrospective chart review and analyzed. 

RESULTS

From May to August 2009, data of 65 patients were collected. Median age was 51 years, 57 % of the patients were female. Most patients (47) had onco-hematological cancers and 18 had solid tumors. Cancer treatment mainly consisted of chemotherapy (46), or stem cell transplantation (SCT) (16). Only 19 of 64 patients had received the 2009 seasonal Influenza vaccine. Clinical presentation included pneumonia (43) and upper respiratory tract infection (22). Forty five of 58 ambulatory patients were admitted. Mechanical ventilation was required in 12 patients (18%). Treatment included oseltamivir monotherapy or in combination with amantadine for a median of 7 days. The global 30-day mortality rate was 18%. All 12 deaths were among the non-vaccinated patients. No deaths were observed among the 19 vaccinated patients. Oxygen saturation <96% at presentation was a predictor of mortality (OR 19.5; 95%CI: 2.28 to 165.9).

CONCLUSIONS

In our cancer patient population, the pandemic 2009 Influenza A (H1N1) virus was associated with high incidence of pneumonia (66%), and 30-day mortality (18.5%). Saturation <96% was significantly associated with death. No deaths were observed among vaccinated patients.

The impact of influenza A(H1N1)pdm09 infection on immunosuppressed patients

Before the advent of the influenza A(H1N1)pdm virus in 2009, the information available about the clinical manifestations and prognosis of influenza in immunosuppressed patients was scarce. With the 2009 pandemic, knowledge of the behavior, severity and importance of antiviral therapy for influenza A infection in immunocompromised hosts has increased considerably. The aim of the present manuscript is to review the main challenges of influenza in the most representative immunosuppressed populations such as solid organ transplant recipients, hematopoietic stem cell transplant recipients, patients with solid and hematological cancer and human immunodeficiency virus infected patients.

A multicenter evaluation of pandemic influenza A/H1N1 in hematopoietic stem cell transplant recipients

BACKGROUND

Hematopoietic stem cell transplant (HSCT) recipients have increased morbidity from respiratory viral infections. Pandemic influenza A - A(H1N1)/pdm09 - in 2009-2010 was associated with increased severity of illness in patients with underlying co-morbidities including HSCT, but the factors that contribute to severe disease in HSCT patients are not well characterized.

METHODS

We conducted a multicenter review of microbiologically proven influenza A(H1N1)pdm09 in the HSCT population between April 2009 and April 2010 to determine factors that are associated with severe disease.

RESULTS

We identified 37 adult patients (26 allogeneic and 11 autologous HSCT recipients). Median time from transplant to diagnosis was 411 days (range 4 days-14.9 years). Three cases were hospital acquired. Twenty-eight of 37 (75.7%) had confirmed A(H1N1)pdm09. Presumed viral lower respiratory tract infection was present in 12/37 (32.4%) patients. Antiviral therapy was given to 33/37 (89%) patients, primarily oseltamivir (n = 24) and oseltamivir before or after another antiviral (n = 8). Excluding those with nosocomial A(H1N1)pdm09, 18/34 (52.9%) were hospitalized and 6 (33%) required admission to an intensive care unit. Mortality within 30 and 60 days of symptom onset was 7/37 (18.9%) and 11/37 (29.7%), respectively. Factors associated with mortality included nosocomial acquisition (P = 0.023), receipt of mycophenolate mofetil (P = 0.001), or antilymphocyte antibody (P = 0.005) within the past 6 months, reduced-intensity conditioning (P = 0.027), and bacteremia (P = 0.021).

CONCLUSIONS

A(H1N1)pdm09 infection was particularly severe in HSCT recipients, specifically among those receiving augmented immunosuppression for graft-versus-host disease. The high mortality of the nosocomial cases highlights the need for strict infection-control measures in hospitals during influenza outbreaks.

Differences in clinical outcomes after 2009 influenza A/H1N1 and seasonal influenza among hematopoietic cell transplant recipients

It is not known whether pandemic 2009 influenza A/H1N1 (2009 H1N1) leads to more serious disease than seasonal influenza in hematopoietic cell transplant (HCT) recipients. In a retrospective study in HCT recipients with virologically proven influenza virus infection, a total of 161 HCT recipients (18 2009 H1N1, 103 seasonal influenza A, and 40 seasonal influenza B) were analyzed. In multivariable analyses, more patients with 2009 H1N1 had lower respiratory tract disease (LRD), hypoxemia, and prolonged viral shedding compared with seasonal influenza A. Seasonal influenza A and B outcomes were similar. There was no difference in overall and influenza-associated mortality among influenza virus types. Both early and delayed administration of antiviral therapy was shown to be beneficial in terms of decreased rates of development of LRD, although earlier intervention appeared to be more effective. Profound lymphopenia and lack of early antiviral therapy were associated significantly with LRD, hypoxemia, and death. High-dose corticosteroid treatment (≥ 1 mg/kg) given at the time of influenza diagnosis was associated with a reduced risk for mechanical ventilation. Thus, our data suggest that infection with 2009 influenza A/H1N1 resulted in more severe respiratory disease in HCT recipients compared with seasonal influenza.