Community acquired influenza requiring hospitalization: vaccine status is unrelated to morbidity in children with cancer

Diagnostic difficulties of AH1N1 influenza infection in children with acute lymphoblastic leukemia: Two case reports

INTRODUCTION

Children with acute lymphoblastic leukemia (ALL) are at a risk of developing influenza-related complications. Approximately 10% of influenza-infected children with ALL or other types of cancer need intensive care, and 5% of them eventually die.

PATIENTS' CONCERNS

We report 2 children with ALL and the swine-origin influenza A virus infection. Diagnosing influenza in them was a challenge. Medical records of these children were reviewed for demographic, clinical, and laboratory data. Patients were hospitalized in the Department of Pediatric Hematology, Oncology, and Transplantology of the Medical University of Lublin, Poland. Case 1 involved a 2-year-old girl who, according to acute lymphoblastic leukemia intercontinental Berlin-Frankfürt-Münster protocol 2009, started chemotherapy in July 2015. She was categorized in the intermediate risk group and received the induction and consolidation phase of the therapy without severe complications. The reinduction therapy was administered in the outpatient department till the 15 day. On the 20 day of this phase, she was admitted to our department with fever, mucositis, tachypnea, abdominal pain, and diarrhea. In September 2009, a 14-year-old boy (case 2) who, according to acute lymphoblastic leukemia intercontinental Berlin-Frankfürt-Münster protocol 2002, was categorized in the high-risk (HR) group, received the induction (Protocol I) phase of therapy without severe complications. On the 7 day of the HR-1 course, he manifested fever and strong, tiring cough, followed by strong mucositis. Chemotherapy had to be interrupted in both children.

DIAGNOSIS

Respiratory viral infections, causing pneumonia, occurred in both patients during anticancer treatment. Initially, the real-time polymerase chain reaction test for the swine-origin influenza A was negative in both patients, which delayed the diagnosis. Additionally, bacterial, and fungal complications were also observed.

INTERVENTIONS

Both patients received oseltamivir twice a day, a broad-spectrum antibiotic, antifungal drug, and granulocyte colony growth factor.

OUTCOMES

The disease progressed quickly, and our patients subsequently died.

CONCLUSION

We speculated that early antiviral treatment can help in the better management of patients in the HR group. It is also important to minimize influenza morbidity and mortality by vaccinating family members, using empiric therapy, providing immediate antiviral therapy, and educating parents about hygiene measures.

Epidemiology and clinical characteristics of viral infections in hospitalized children and adolescents with cancer in Lebanon

Background

Viral infections in children and adolescents with malignancy are commonly encountered and have a significant impact on morbidity and mortality. Studies and epidemiological data regarding viral infections in children with cancer in developing countries are lacking. This retrospective cohort study aims to assess the burden of viral infections in children and adolescents with cancer, by assessing prevalence, risk factors, as well as morbidity and mortality of common viruses over a period of 8 years.

Methods and findings

Medical records of cancer patients treated at the Children Cancer Center of Lebanon were reviewed and 155 participants under the age of 21 were identified with at least one documented viral infection during the period from July 2009 to November 2017. This subset included 136 participants with active malignancy and 19 participants with a history of cancer who underwent hematopoietic stem cell transplantation [HSCT] and were in remission; the latter group was analyzed separately. Information regarding participant characteristics, hospital course, and complications were obtained. Associations between viral infections and certain factors were assessed. In the cohort, 64% were male, 81% were Lebanese. In participants with active malignancy, 90% received chemotherapy in the 6 months preceding the viral infection episode, 11% received radiotherapy. 51% of participants were neutropenic at the time of viral detection, and 77% were lymphopenic. 17% experienced a bacterial co-infection, and 3 experienced a viral co-infection. Among 162 viral infection episodes, clinically diagnosed skin infections, mainly herpes simplex virus type 1 and varicella-zoster virus, were the most common [44% of cases]. These were followed by laboratory-proven systemic herpes infections: cytomegalovirus [14%] and Epstein-Barr virus [6%]. Respiratory viruses: influenza and respiratory syncytial virus, accounted for 9% and 4%, respectively, whereas rotavirus represented 11% and BK virus represented 3% of cases. Acute lymphocytic leukemia was the most prevalent neoplasia [57%]. Fever was the most common presenting symptom [55%] and febrile neutropenia was the reason for admission in 24% of cases. The mean length of stay was significantly longer in participants with cytomegalovirus infections and significantly lower in rotavirus infection. Admission to the ICU occurred in 9%, complications in 8%, and mortality in 5%. Participants with viral infections post-HSCT were noted to have a significantly longer length of hospital stay compared to non-HSCT participants, with no other significant differences in clinical course and outcome. The study was limited by its retrospective nature and by the late introduction and underuse of multiplex PCR panels, which may have led to underdiagnosis of viral infections.

Conclusions

Viral infections were prevalent in our sample of cancer patients and may have contributed to morbidity and mortality. Newly available viral diagnostics are likely to vastly increase the number and scope of detectable viral infections in this population. Prospective studies using multiplex PCR technology with systematic testing of patients will be more helpful in defining the burden of viral infections. Furthermore, efforts at antimicrobial stewardship would benefit from the identification of viral causes of infection and limit the unnecessary use of antibiotics in the pediatric cancer population.

Influenza in Children With Special Risk Medical Conditions: A Systematic Review and Meta-analysis

BACKGROUND

Children with special risk medical conditions (SRMC) are over-represented in influenza hospitalizations. A systematic review was undertaken to determine whether children with SRMCs experience greater complications or severity following influenza infection.

METHODS

Bibliographies of pertinent articles were searched in MEDLINE and EMBASE (1990 to March 2018) and contact made with the investigators of unpublished studies containing relevant data. Studies of children (aged ≤18 years) with a SRMC hospitalized with influenza were included. Outcomes were pneumonia, intensive care unit (ICU) admission, mechanical ventilation, neurologic outcomes (seizures, encephalopathy), death and length of stay in hospital or ICU.

RESULTS

Twenty-two studies met inclusion criteria. Compared with healthy peers, children with SRMC had higher odds of ICU admission [pooled odds ratio (OR) 1.66 (95% confidence interval (CI): 1.25-2.21)], for mechanical ventilation [pooled OR 1.53 (95% CI: 0.93-2.52)] and death [pooled OR 1.34 (95% CI: 0.74-2.41)]. Additionally, children with SRMC were more likely to develop bacterial pneumonia (crude OR 1.7; 95% CI: 1.1-2.6) or experience prolonged hospital length of stay [adjusted rate ratio 1.75 (95% CI: 1.44-2.11)]. The level of GRADE evidence was low for all outcomes considered in this review.

CONCLUSIONS

While there was evidence that ICU management and bacterial pneumonia increases in children with SRMC, evidence showing an increase in the probability of death or need for mechanical ventilation was inconsistent. Further research using large datasets should evaluate the impact of complications and associated morbidity from influenza in SRMC children.

Immune response to influenza vaccination in children with cancer

The aim of this study was to evaluate the ability of influenza immunization to evoke a protective immune response among children with cancer. We evaluated 75 children with cancer who received influenza vaccination. Hemagglutination Inhibition Antibody titers were determined before and after vaccination. The protective rates after vaccination were 79% for H1N1, 75% for H3N2 and 59% for influenza B virus whereas the seroconversion rates were 54%, 44% and 43% respectively. The differences pre- and post-vaccination were significant regardless the method which was used: seroprotection changes, seroconversion and geometric mean titers analyses. Variables such as the pre-vaccination antibody titers, the time when the responses were measured after the vaccination, the age and the type of malignancy as well as the absolute lymphocyte count were found to be correlated with the immune response but the findings were different for each vaccine subunit. In conclusion, influenza vaccination provides protection in a remarkable proportion of pediatric cancer patients whereas this protection is more obvious against H1N1 and H3N2 compared to influenza B. The immune response after vaccination is significant and seems to be influenced by a variety of factors.

Serologic response and clinical efficacy of influenza vaccination in children and young adults on chemotherapy for cancer

BACKGROUND

Influenza is a health risk to children receiving chemotherapy for cancer. An absolute lymphocyte count (ALC) >1,000 cells/mm(3) has been associated with the ability to produce an immune response to influenza vaccine during chemotherapy. However, clinical efficacy of influenza vaccination during chemotherapy remains unclear.

PROCEDURE

We conducted a prospective cohort study in children receiving chemotherapy for cancer during two consecutive influenza seasons. Assessments of immune cells and serologic response were measured immediately before and after receiving influenza vaccine. Patients were monitored for influenza or influenza-like illness (ILI).

RESULTS

Two hundred fifty-nine patients were studied over 2 years. The seroresponse rate was 62% (98/157). The median ALC at vaccination was higher in seroresponders than nonresponders, 854 cells/mm(3) versus 602 cells/mm(3) , respectively (P < 0.036). Univariate analysis showed that patients with an ALC <1,000 cells/mm(3) at the time of vaccination were twice as likely to be sero-nonresponders (P < 0.02, OR = 2.4, 95% CI: 1.1-5.0). Twelve percent (31/259) of patients developed influenza, of whom all had fever at presentation, 26% (8/31) required hospitalization, and 81% (25/31) had chemotherapy delays. No deaths were associated with influenza infection. The proportion of patients with influenza was not different between seroresponders and nonresponders.

CONCLUSIONS

Influenza infection following immunization remains a source of morbidity in children undergoing chemotherapy. Lymphopenia at vaccination predicted sero-nonresponse. Seroresponse was not associated with a decreased frequency of influenza infection or ILI when compared to sero-nonresponders, suggesting clinical effectiveness of vaccination is likely multifactorial. Further investigation into the efficacy of the influenza vaccine is needed to refine immunization recommendations.

Immunogenicity and clinical effectiveness of the trivalent inactivated influenza vaccine in immunocompromised children undergoing treatment for cancer

Influenza is associated with significant morbidity and mortality in children receiving therapy for cancer, yet recommendation for, and uptake of the seasonal vaccine remains poor. One hundred children undergoing treatment for cancer were vaccinated with the trivalent inactivated influenza vaccine according to national guidelines in 2010 and 2011. Influenza‐specific hemagglutinin inhibition antibody titers were performed on blood samples taken prior to each vaccination and 4 weeks following the final vaccination. A nasopharyngeal aspirate for influenza was performed on all children who developed an influenza‐like illness. Following vaccination, seroprotection and seroconversion rates were 55 and 43% for H3N2, 61 and 43% for H1N1, and 41 and 33% for B strain, respectively. Overall, there was a significant geometric mean fold increase to H3N2 (GMFI 4.56, 95% CI 3.19–6.52, P < 0.01) and H1N1 (GMFI 4.44, 95% CI 3.19–6.19, P < 0.01) strains. Seroconversion was significantly more likely in children with solid compared with hematological malignancies and in children <10 years of age who received a two‐dose schedule compared to one. Influenza infection occurred in 2% of the vaccinated study population, compared with 6.8% in unvaccinated controls, providing an adjusted estimated vaccine effectiveness of 72% (95% CI −26–94%). There were no serious adverse events and a low reactogenicity rate of 3%. The trivalent inactivated influenza vaccine is safe, immunogenic, provides clinical protection and should be administered annually to immunosuppressed children receiving treatment for cancer. All children <10 years of age should receive a two‐dose schedule.

Burden of Influenza-Related Hospitalizations and Attributable Mortality in Pediatric Acute Lymphoblastic Leukemia

BACKGROUND

Influenza can be severe in patients with underlying malignancy; however, the rate of influenza hospitalizations and attributable mortality in children with cancer is unknown.

METHODS

We performed a retrospective cohort study among 10 698 children with new-onset acute lymphoblastic leukemia (ALL) from 41 US children's hospitals between January 1999 and September 2011. Influenza-related hospitalizations were identified using ICD-9 discharge diagnosis codes, excluding hospitalizations during low-prevalence influenza periods. Follow-up was censored at the earliest of 5 events: end of study period, expected end of chemotherapy, last known hospitalization, hematopoietic stem cell transplant, or death. Data were collected on hospitalization characteristics and resource utilization. Hospitalization rates were calculated using season-adjusted person-time. Crude attributable in-hospital mortality was calculated using baseline mortality for noninfluenza hospitalizations during the same period. Subgroup analysis was performed by time from ALL diagnosis and by age category.

RESULTS

The rate of influenza-related hospitalizations was 618.3 per 100 000 person-months. Rates were similar by time from ALL diagnosis and across age categories. Overall attributable in-hospital mortality was 1.0% (95% confidence interval [CI], 0.3%-2.3%) and was highest for children <6 months from diagnosis (1.6%; 95% CI, 0.4%-4.5%) and children <2 years of age (6.7%; 95% CI, 1.3%-22.7%). Total length of stay, days of broad-spectrum antibiotic exposure, and duration of intensive care were significantly greater for influenza-related hospitalizations compared with noninfluenza hospitalizations.

CONCLUSIONS

The burden of influenza-related hospitalizations in children with ALL is high and associated with significantly increased resource utilization and attributable mortality.

A prospective study of chemotherapy immunologic effects and predictors of humoral influenza vaccine responses in a pediatric oncology cohort

BACKGROUND

Pediatric oncology patients represent a cohort of individuals uniquely at risk of complications from influenza, yet less likely to respond to the vaccine. It is not yet clear how to best protect this vulnerable population.

METHODS

We performed a prospective analysis of 177 pediatric oncology patients to define the predictors of influenza vaccine responses. Each variable was examined over three time points and a repeated measure analysis was performed.

RESULTS

Patients with ALL vaccinated during induction phase had superior influenza vaccine responses than those subjects vaccinated during post-induction or maintenance phases (P=0·0237). Higher aggregate HAI titer responses were associated with a higher baseline B-cell count (P=0·0240), and higher CD4 and CD8 influenza-specific T-cell responses, suggesting prior antigen exposure is a significant contributor. The solid tumor cohort had equivalent responses during all time frames of chemotherapy.

DISCUSSION

The optimal protection from influenza of pediatric patients on chemotherapy should include vaccination, but it is clear that not all patients produce high titers of antibodies after vaccination. This study identified biomarkers that could be used to individualize vaccine approaches. Immunologic predictors might have a role in targeting resources, as B-cell counts predicted of vaccine responses among the patients with ALL.

Protecting pediatric oncology patients from influenza

Influenza is a common respiratory pathogen. Its severity can be unpredictable, but people with chronic illness are at increased risk of severe infection, complications, and death from influenza. This review examines evidence to support various strategies to protect pediatric oncology patients from influenza-related morbidity. Influenza vaccination should be considered standard. Additional evidence-supported measures include antiviral treatment, antiviral prophylaxis, cohorting of patients, and hospital infection control measures. Data from other high-risk populations support the vaccination of family members, double-dose or high-dose vaccination, and the use of barrier methods. These measures have the potential to optimize patient outcomes because there will be fewer treatment interruptions for acute illness. These strategies can also protect patients from prolonged hospitalizations and morbidity related to influenza.

The effect of physician's recommendation on seasonal influenza immunization in children with chronic diseases

BACKGROUND

Despite recommendations by Health Authorities, influenza immunization coverage remains low in children with chronic diseases. Different medical providers involved in the management of children with chronic conditions may affect the pattern of influenza vaccine recommendations and coverage. The likelihood of vaccination by type of provider in children with chronic conditions is poorly understood. Therefore, the objectives of this study were to analyze the pattern and the effect of recommendations for seasonal influenza immunization provided by different physician profiles to families of children with chronic diseases and to measure the frequency of immunization in the study population.

METHODS

We recruited children with chronic diseases aged 6 months-18 years who subsequently presented to specialty clinics for routine follow-up visits, during spring 2009, in three Italian Regions Families of children with chronic diseases were interviewed during routine visits at reference centers through a face-to-face interview. We analyzed the following immunization predictors: having received a recommendation toward influenza immunization by a health provider; child's sex and age; mothers and fathers' age; parental education and employment; underlying child's disease; number of contacts with health providers in the previous year. Influenza immunization coverage was calculated as the proportion of children who received at least one dose of seasonal influenza vaccine in the previous season. We calculated prevalence ratios and we used a generalized linear model with Poisson family, log link and robust error variance to assess the effect of socio-demographic variables, underlying diseases, and recommendations provided by physicians on influenza immunization.

RESULTS

We enrolled 275 families of children with chronic diseases. Overall influenza coverage was 57.5%, with a low of 25% in children with neurological diseases and a high of 91.2% in those with cystic fibrosis. While 10.6% of children who did not receive any recommendation toward influenza immunization were immunized, among those who received a recommendation 87.5-94.7% did, depending on the health professional providing the recommendation. Receiving a recommendation by any provider is a strong predictor of immunization (PR = 8.5 95% CI 4.6;15.6) Most children received an immunization recommendation by a specialty (25.8%) or a family pediatrician (23.3%) and were immunized by a family pediatrician (58.7%) or a community vaccinator (55.2%).

CONCLUSIONS

Receiving a specific recommendation by a physician is a strong determinant of being immunized against seasonal influenza in children with chronic diseases independently of other factors. Heterogeneity exists among children with different chronic diseases regarding influenza recommendation despite international guidelines. Increasing the frequency of appropriate recommendations toward influenza immunization by physicians is a single powerful intervention that may increase coverage in children with chronic conditions.

Clinical and demographic characteristics of seasonal influenza in pediatric patients with cancer

BACKGROUND

Changes in oncology care and the diagnosis and management of influenza over the past several decades may have altered the epidemiology and outcomes of influenza in pediatric oncology patients.

METHODS

The clinical features and outcomes of 102 pediatric patients undergoing cancer therapy during 107 episodes of influenza between January 2002 and April 2009 were retrospectively ascertained.

RESULTS

Median age at the time of influenza was 7.2 years (interquartile range: 3.8-11.2 years); 46% of patients were male. Nineteen patients (18%) were recipients of hematopoietic stem cell transplants. Patients' median absolute neutrophil and lymphocyte counts were 1300/μL (interquartile range: 500-2967/μL) and 360/μL (interquartile range: 180-836/μL), respectively. Twelve patients (11%) had coinfections with influenza and one or more other respiratory pathogens. Influenza prompted patients' hospitalization during 64% of episodes, and 75% received antiviral therapy. Complications occurred in 30% of infections and serious complications occurred in 7%. Three patients died, but no deaths were directly attributable to influenza. Most patients had delays in cancer therapy; the median delay was 5 days. Neutropenia, concurrent infection, increasing age and having received hematopoietic stem cell transplant increased the risk of serious complications.

CONCLUSIONS

Advances in the management of pediatric cancer and influenza have not altered the epidemiology and outcome of influenza in oncology patients. Clinical features identify subgroups of patients with influenza who are at risk of poor outcomes and those with a good prognosis.

H1N1 infection in children with haematological and oncological diseases in Norway

AIM

  To describe the impact of H1N1 infections in children with haematological and oncological diseases during the 2009 H1N1 pandemics.

METHODS

  A short questionnaire was e-mailed to all paediatric departments taking care of patients with oncological and chronic haematological diseases, asking for known cases of H1N1 infections in this patient group.

RESULTS

  Nine children treated for cancer and seven children with haematological diseases were registered. No death occurred, but two patients treated for cancer (acute lymphoblastic leukaemia at diagnosis, acute myeloid leukaemia in chemotherapy-induced bone marrow aplasia) experienced life-threatening respiratory complications.

CONCLUSION

  In all patients with haematological disease and most cases of oncological diseases, the infections ran a mild course. However, life-threatening complications occurred in severely immunosuppressed and neutropenic patients. Delay of anticancer treatment is a concern even in mild cases.