Influenza immunization practices among pediatric oncologists

Influenza activity and regional mortality for non-small cell lung cancer

Lung cancer is the leading cause of cancer deaths in the United States and worldwide. While influenza illness is known to be particularly dangerous for frail and elderly patients, the relationship between influenza illness and outcomes in patients with cancer remains largely unknown. The Surveillance, Epidemiology, and End Results (SEER) database was queried to identify patients with non-small cell lung cancer (NSCLC) diagnosed between 2009 and 2015. Influenza-like illness (ILI) activity, provided by the Outpatient Influenza-like Illness Surveillance Network of the Center of Disease for Control and Prevention, was merged with the SEER dataset on the state-month level. Regional monthly mortality rates were compared during low versus high flu months in this ecological cohort study. 202,485 patients with NSCLC from 13 SEER-reporting states were included in the analysis. 53 of 1049 state-months (5.1%) had high flu activity. Monthly mortality rates during low and high flu months were 0.041 (95% CI 0.041-0.042) and 0.051 (95% CI 0.050-0.053), respectively (RR 1.24 [95% CI 1.21-1.27]). The association between ILI activity and mortality was observed at the individual state level and in all clinical and regional subgroups. Increased regional influenza activity is associated with higher mortality rates for patients with NSCLC. Vaccine-directed initiatives and increased awareness amongst providers will be necessary to address the growing but potentially preventable burden of influenza-related lung cancer deaths in the U.S.

Lessons learnt from influenza vaccination in immunocompromised children undergoing treatment for cancer

Influenza infection contributes substantially to global morbidity and mortality, with children undergoing treatment for cancer among the most vulnerable due to immunosuppression associated with disease and treatment. However, influenza remains one of the most common vaccine-preventable diseases. Despite international guidelines recommending inactivated influenza vaccination on the basis of data supporting efficacy and an excellent safety profile in this population, uptake has often been suboptimal due to persisting hesitancy among both patients and oncologists regarding the ability of the vaccine to mount a sufficient immune response, the optimal vaccine schedule and timing, and the best method to assess response in immunocompromised populations. In this Review, we discuss the evidence regarding influenza vaccination in children with cancer, factors that influence response, and highlight strategies to optimise vaccination. Host immune factors play a substantial role, thus principles learnt from influenza vaccination can be broadly applied for the use of inactivated vaccines in children with cancer.

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.

A Quality Improvement Initiative to Increase and Sustain Influenza Vaccination Rates in Pediatric Oncology and Stem Cell Transplant Patients

Introduction:

Influenza vaccination of pediatric oncology and stem cell transplant (SCT) patients is crucial due to high risk of complications. Achieving high vaccination rates to prevent illness is often limited by competing demands and intensive treatment. A quality improvement (QI) initiative beginning influenza season 2012–2013 aimed to achieve and sustain high vaccination rates in active patients > 6 months of age, receiving cancer therapy or SCT within 6 months before or at any time during the season, and > 100 days after allogeneic SCT.

Methods:

We identified key drivers and barriers to success from an initially developed vaccination process that proved to be burdensome. Change ideas were implemented through multiple tests of change during the QI initiative. Iterations within and across 4 subsequent seasons included patient identification through chemotherapy orders, provider education, incorporating vaccination into routine work-flow, continuous data analysis and feedback, and use of new reporting technology.

Results:

Initial vaccination rates were < 70%, increasing to 89% after the QI initiative began and subsequently sustained between 85% and 90%. Active patients were significantly more likely to be vaccinated during the initiative (odds ratio, 3.7; 95% CI, 2.9–4.6) as compared with the first 2 seasons.

Conclusions:

High influenza vaccination rates can be achieved and maintained in a pediatric oncology/SCT population using strategies that correctly identify patients at highest risk and minimize process burden.

Paediatrician beliefs and practices around influenza vaccination

AIM

The uptake of influenza vaccination in children with high-risk medical conditions continues to be low in Australia and internationally. We aimed to determine Australian paediatricians' beliefs and practices around the influenza vaccination of children.

METHODS

This was conducted as a cross sectional survey of paediatricians from two tertiary paediatric hospitals in Sydney.

RESULTS

There were 101 participants. Influenza vaccination was not prioritised compared with other vaccines and clinical issues, with fewer than half of respondents strongly agreeing that influenza vaccination was useful. Paediatricians' knowledge of guidelines and recommendations in this area was suboptimal. Interventions thought most likely to improve vaccine coverage included better education of doctors, greater vaccine availability in outpatient clinics and automated reminder systems.

CONCLUSION

The inclusion of influenza vaccine on the standard Australian immunisation schedule may be required to improve vaccine coverage in high-risk children.

Immunization practices in acute lymphocytic leukemia and post-hematopoietic stem cell transplant in Canadian Pediatric Hematology/Oncology centers

There are no Canadian immunization guidelines for children treated for malignancy. Guidelines do exist for patients who underwent hematopoietic stem cell transplant (HSCT), but they provide broad timeframes for initiating vaccination; there is no standard schedule. The optimal approach to immunization in these populations is unclear. We sought to describe immunization practices at Canadian Pediatric Hematology/Oncology centers. A 43-item online questionnaire was distributed to the 16 programs in the C(17) research network of pediatric hematology/oncology centers to capture information on timing and criteria for immunization of patients with acute lymphocytic leukemia (ALL) and those who have undergone HSCT. At each center, 1-2 physicians or pharmacists completed the survey to reflect center-wide immunization practices. Responses were received from 11/16 (69%) programs; 11 respondents reported on practices for patients with ALL and 9 reported on practices for patients who are post-HSCT. In 5/11 ALL programs (45%) re-immunization is recommended routinely after chemotherapy, starting 3-6 months post-chemotherapy. In HSCT programs, timing of pneumococcal conjugate vaccination (PCV) varied from 3 months post-HSCT (4 programs) to 12 months post-HSCT (4 programs). Live vaccines were administered 24 months post-HSCT in 8/9 programs. All HSCT programs considered graft-versus-host-disease and 7 considered discontinuation of immunosuppression in immunization decisions. Pediatric hematology/oncology programs were divided in regards to re-immunization of patients with ALL post-chemotherapy. After HSCT, timing of PCV administration varied, with 4 programs initiating immunization later than Canadian guidelines recommend (3-9 months post-HSCT). These findings suggest a need to standardize immunization practices in these populations.

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.

Attitudes and Practices Regarding Influenza Vaccination Among Healthcare Workers Providing Services to Individuals With Spinal Cord Injuries and Disorders

Objective:

To examine influenza vaccination status and predictors for vaccine receipt among healthcare workers (HCWs) caring for patients with spinal cord injuries and disorders.

Design:

Cross-sectional, nationwide anonymous survey.

Setting:

Twenty-three Veterans Affairs spinal cord injury centers.

Participants:

One thousand five hundred fifty-six HCWs.

Methods:

The primary outcome was staff vaccination status. Independent variables included staff demographic and employment characteristics, health status, attitudes and beliefs about the vaccine, and implications for its use.

Results:

The staff vaccination rate was 51%. Leading motivators of vaccine receipt were self-protection (77%) and patient protection (49%). The most common reasons for nonreceipt were concerns about side effects (49%), preventive quality (20%), and inconvenience (14%). Logistic regression results suggested that age of 50 years or older (OR, 1.47; P = .021), male gender (OR, 2.50; P < .001), strong belief in vaccine effectiveness (OR, 19.03; P = .008), and importance of HCW vaccination (OR, 20.50; P = .005) significantly increased the probability of vaccination. Recommending the vaccine to coworkers, patients, or patients' families was also associated with HCW vaccination (OR, 3.20; P < .001). Providers who did not believe the vaccine was protective (P < .001) or effective P < .001) were less likely to recommend it to patients.

Conclusions:

Strategies to increase vaccination rates among HCWs should address concerns about side effects, effectiveness, and protective value of the vaccine and access to it. The impact of provider recommendations should be stressed. Vaccination and subsequent prevention of illness may limit morbidity and mortality, thus benefiting HCWs, healthcare facilities, and patients.

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.

Compliance with immunization against H1N1 influenza virus among children with cancer

In this report, we describe the experience with immunization against pandemic influenza A H1N1 in children with cancer treated at a pediatric oncology department during the pandemic season (2009). According to the guidelines, vaccination of all children with cancer receiving chemotherapy as well as those who had completed treatment was scheduled. Among the 140 children who were eligible for immunization, 122 were immunized, achieving a compliance rate of 87% despite negative publicity and low vaccine uptake in the general population. The vaccine was tolerated and none of the vaccinated children developed influenza. It is concluded that high immunization rates can be achieved among pediatric oncology patients.

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.

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.

Epidemiology and potential preventative measures for viral infections in children with malignancy and those undergoing hematopoietic cell transplantation

In pediatric patients with malignancy and those receiving hematopoietic stem cell transplants, bacterial and fungal infections have been the focus of fever and neutropenia episodes for decades. However, improved diagnostic capabilities have revealed viral pathogens as a significant cause of morbidity and mortality. Because of limited effective antiviral therapies, prevention of viral infections is paramount. Pre-exposure and post-exposure prophylaxis and antiviral suppressive therapeutic approaches are reviewed. Additionally, infection control practices specific to this patient population are discussed. A comprehensive approach utilizing each of these can be effective at reducing the negative impact of viral infections.

Economic value of influenza vaccination

Influenza epidemics are responsible for high mortality and morbidity rates in particular among elderly and high risk groups. This review is aimed at assessing the economic value of vaccination in these groups. A search of full economic evaluations of influenza vaccination in comparison with no interventions was performed on PubMed from January 1990 to May 2011. Only economic evaluations dealing with elderly and high risk groups were considered. The quality of selected articles was assessed through Drummond's checklist. Sixteen cost-effectiveness analyses and four cost-benefit analyses were included: overall, the quality of studies was fairly good. The vaccination was demonstrated to be cost-effective or cost-saving in almost all studies, independently by the perspective and the type of analysis. Influenza vaccination is a worthwhile intervention from the pharmacoeconomic view-point, anyway a standardization of methods should be desirable in order to guarantee the comparability and transferability of results.

Immune response to 2009 pandemic H1N1 influenza virus A monovalent vaccine in children with cancer

PURPOSE

This study investigated the immune response to 2009 pandemic H1N1 influenza monovalent vaccine in children with cancer receiving chemotherapy.

METHODS

We enrolled 25 pediatric patients. Ten patients younger than 10 years old received two vaccinations and the remaining 15 patients older than 10 years old received one. We checked hemagglutination-inhibition (HAI) antibody titers in sera of patients before and 3-4 weeks after vaccination. Seroprotective titer was defined as HAI antibody titer ≥ 40 and seroresponse as ≥ 4-fold increase in HAI antibody titers after vaccination.

RESULTS

The pre- and post-vaccination seroprotective rates were 52% and 72% (P = 0.24). Sixteen (64%) patients were possibly exposed to 2009 pandemic H1N1 influenza previously, and there was significant association between possible exposure and pre-vaccination seroprotective rate (P = 0.03). Post-vaccination seroresponse rate was 32%, and seroresponse was greater in patients without pre-vaccination seroprotective titer than those with pre-vaccination seroprotective titer (50% vs. 15%, P = 0.07). Children with lymphocyte counts above 1,500/µl during vaccination period had better seroresponse than those with lymphocyte counts below 1,500/µl (P = 0.008). Post-vaccination geometric mean titer (GMT) significantly increased in patients younger than 10 years receiving two vaccinations (pre- and post-vaccination GMT were 21.4 and 60.6, respectively; P = 0.025).

CONCLUSIONS

Monovalent vaccine for the 2009 pandemic H1N1 influenza A was found to be partially immunogenic in children with cancer, as evidenced by 32% of seroresponse rate. Immune response can be improved with vaccinations administered to patients whose absolute lymphocyte counts returned to a level of 1,500/µl or higher.

Vaccines for prophylaxis of viral infections in patients with hematological malignancies

BACKGROUND

Viral infections cause significant morbidity and mortality in patients with hematological malignancies. It remains uncertain whether viral vaccinations in these patients are supported by good evidence.

OBJECTIVES

We aimed to determine the effectiveness and safety of viral vaccines in patients with hematological malignancies.

SEARCH STRATEGY

We searched Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, CINAHL (June 2010), reference lists of relevant papers, abstracts from scientific meetings and contacted vaccine manufacturers.

SELECTION CRITERIA

Randomized controlled trials (RCTs) evaluating viral vaccines in patients with hematological malignancies were included.

DATA COLLECTION AND ANALYSIS

Relative risk (RR) was used for binary data and mean difference (MD) for continuous data. Primary outcome was incidence of infection. Secondary outcomes were mortality, incidence of complications and severe viral infection, hospitalization, immune response and adverse effects. Fixed-effect model was used in meta-analyses.

MAIN RESULTS

Eight RCTs were included, with 305 patients in the intervention groups and 288 in the control groups. They evaluated heat-inactivated varicella zoster virus (VZV) vaccine (two trials), influenza vaccines (five trials) and inactivated poliovirus vaccine (IPV) (one trial). Seven trials had high and one trial had moderate risk of bias.VZV vaccine might reduce herpes zoster compared to no vaccine (RR 0.54, 95% CI 0.3 to 1.0, P=0.05), but not statistically significant. Vaccination also demonstrated efficacy in immune response but frequently caused local adverse effects. One trial reported severity score of zoster, which favored vaccination (MD 2.6, 95% CI 0.94 to 4.26, P=0.002).Two RCTs compared inactivated influenza vaccine with no vaccine and reported lower risk of lower respiratory infections (RR 0.39, 95% CI 0.19 to 0.78, P=0.008) and hospitalization (RR 0.17, 95% CI 0.09 to 0.31, P<0.00001) in vaccine recipients. However, vaccine recipients more frequently experienced irritability and local adverse effects. There was no significant difference in seroconversion between one and two doses of influenza vaccine (one trial), or between recombinant and standard influenza vaccine (one trial), or influenza vaccine given with or without re-induction chemotherapy (one trial).The IPV trial comparing vaccination starting at 6 versus 18 months after stem cell transplant (SCT) found no significant difference in seroconversion.

AUTHORS' CONCLUSIONS

Inactivated VZV vaccine might reduce zoster severity in adult SCT recipients. Inactivated influenza vaccine might reduce respiratory infections and hospitalization in adults with multiple myeloma or children with leukemia or lymphoma. However, the quality of evidence is low. Local adverse effects occur frequently. Further high-quality RCTs are needed.

Utility of Influenza Vaccination for Oncology Patients

Every fall and winter, patients with cancer and their families ask oncologists whether they should be vaccinated for influenza. This season, with escalating concerns regarding the novel H1N1 influenza virus and its recently approved vaccine, this question has become more frequent and increasingly urgent. The purpose of this article is to review evidence related to the ability of patients with cancer to mount protective immunological responses to influenza vaccination. The literature on immunogenicity in pediatric and adult patients, those with solid tumors and hematologic malignancies, untreated and actively treated patients, and patients receiving biologic agents is summarized and reviewed. In addition, we report on potential strategies to improve the efficacy of influenza vaccination in patients with cancer, such as the timing of vaccination, use of more than a one-shot series, increasing the antigen dose, and the use of adjuvant therapies. We conclude that there is evidence that patients with cancer receiving chemotherapy are able to respond to influenza vaccination, and because this intervention is safe, inexpensive, and widely available, vaccination for seasonal influenza and the novel H1N1 strain is indicated.

Immunogenicity of trivalent influenza vaccine in children with acute lymphoblastic leukemia during maintenance therapy

PURPOSE

The aim of this study was to assess the immune response of children with acute lymphoblastic leukemia (ALL) to influenza vaccine and to compare it with healthy controls.

PROCEDURE

Thirty-two children aged 1-18 years with ALL on maintenance therapy and 30 healthy sibling controls were enrolled in the study. All children were vaccinated with trivalent inactivated influenza vaccine. Hemagglutinin-inhibition (HI) antibody titers were determined in sera of both patient and control groups just before and 4 weeks after vaccination. The ability of each group to mount a protective (> or =40) and/or fourfold titer was measured.

RESULTS

The protective response for virus subunits among patients and healthy controls were 43.4% versus 88% for H1N1 (P = 0.04), 63.3% versus 80% for H3N2 antigens (P = 0.06), and 26% versus 73% for B antigen (P = 0.001). Responses for H1N1 and B subunits were significantly lower in patients than controls. In the patient group, the significant response to each virus was demonstrated in the analysis of pre- and post-vaccination geometric mean titer (GMT) (P = 0.001). The percentage of patients and controls with fourfold increase in HI titers were 56.2% versus 80% for H1N1 (P = 0.04), 40.6% versus 53.3% for H3N2 (P = 0.31), and 59.4% versus 83.3% for B (P = 0.038). Immune responses for H1N1 and B subunits were significantly lower in patients than controls.

CONCLUSIONS

Influenza vaccine is tolerated well in ALL patients with acceptable but limited immune response compared to healthy controls. These findings support the recommendation for annual influenza vaccination in children with ALL.

Infections in pediatric patients with hematologic malignancies

Despite significant advances in supportive care, infection remains second only to malignancy as a cause of death in pediatric oncology patients, and infection accounts for a large fraction of treatment-related costs. Multiple risk factors contribute to infection-related morbidity, chief among them the immunosuppressive effects of leukemia itself and of cytotoxic chemotherapy, prolonged hospitalization and antibiotic use, and loss of barrier integrity associated with mucositis and the need for indwelling central access. While viruses are the most common causes of infection, bacteria are responsible for most life-threatening complications. Gram-negative bacilli are a concern for all patients undergoing treatment, while a subset of gram-positive organisms, particularly viridans streptococci, become significant pathogens in children receiving profoundly immunosuppressive therapy. Invasive fungal infections are also a serious risk for morbidity and mortality in this population. Availability of new antimicrobial agents has made it possible to treat infectious complications more effectively, but their availability is also leading to an increased prevalence of highly resistant pathogens. Future work in pediatric oncology will need to include measures to reduce the immunosuppressive effects of anti-cancer therapy, provide targeted treatment for infections, and better identify groups of patients at high risk for infectious complications, who may benefit from antimicrobial prophylaxis or more aggressive empirical therapy.

Cost-effectiveness of influenza immunization in adult cancer patients in Taiwan

The aim of this study was to investigate the efficacy of the influenza vaccine among cancer patients in Taiwan. We determined the effect of immunization on the following outcomes of disease: hospitalizations, emergency department visits, hospital outpatient visits, physician office visits, and deaths. Cost-effectiveness was analysed from the perspectives of the healthcare system and society. A decision tree was used, with estimates of disease burden and costs based on data from published and unpublished sources. The model followed 34 112 cancer patients aged 20-64 years who were registered by the Taiwan National Cancer Registry in 2002. An influenza immunization programme for the cancer population would prevent 2555 cases of all types of influenza infection, 660 of which would be serious cases involving hospitalization, emergency department visits and death. From the perspective of the healthcare system, the programme would cost US$7.7 million, providing net savings of US$5.4 million. From a societal perspective, the programme would cost US$28.6 million, providing net savings of US$22.3 million. This corresponds to savings of US$2107 and US$6338 per case averted, from healthcare and societal perspectives, respectively, as well as 110 lives saved. Lesser disease burden, greater vaccine efficacy and lower cost of hospitalizations increased cost-effectiveness. Influenza immunization for cancer patients is cost-saving and cost-effective from a healthcare and societal perspective in Taiwan. We highly recommend annual influenza vaccinations for this patient group.

Influenza-associated morbidity in children with cancer

BACKGROUND

The clinical impact of influenza in children undergoing therapy for cancer is not well-described in the literature.

PROCEDURE

Laboratory-documented influenza infection in pediatric oncology patients cared for in a single regional pediatric medical center between July 2000 and June 2005 was identified by review of medical and laboratory records.

RESULTS

Twenty-seven clinical encounters were identified in 24 pediatric oncology patients with influenza infection. Eighty-three percent of patients were receiving chemotherapy for hematologic or solid malignancies. Two-thirds of patients were hospitalized for a median duration of 7.4 days; 40% of patients experienced a delay in scheduled chemotherapy as result of influenza infection. Most children (67%) were not neutropenic, although 63% were lymphopenic. Importantly, 15% of children with influenza had simultaneously diagnosed bacteremia. Concomitant pathogens included Pseudomonas aeruginosa, Enterobacter cloacae, Enterococcus faecalis, and coagulase-negative Staphylococcus. Primary influenza pneumonia and/or respiratory failure occurred in three children, and ventilatory support was required in four clinical encounters. Antiviral medications were administered to 63% of patients within 2 days of influenza diagnosis.

CONCLUSION

Pediatric oncology patients experienced significant influenza-associated morbidities. Influenza infection should be considered in febrile children with respiratory symptoms during the respiratory viral season, as well as concurrent bacterial or fungal infections.

Immunizations for children with cancer

Children with malignant diseases are at risk of severe outcomes from vaccine preventable infections. Vaccination of these children presents challenges due to efficacy and safety concerns. There is a paucity of data on several aspects of vaccination in this group of children. Consequently, for the most part, data are extrapolated from healthy populations and combined with experts' opinions. This article reviews the use of vaccines in infants and children with cancer. In this context, an all-encompassing review is not the goal. Key principles are reviewed to provide a framework to guide the use of vaccines in children with malignant diseases.

Assessment of the immune response to trivalent split influenza vaccine in children with solid tumors

PURPOSE

To assess the immune response to influenza vaccine in children with solid tumors receiving chemotherapy or under the influence of chemotherapy.

METHODS

Forty-five children (aged 1-18) with solid tumors on chemotherapy or within 6 months of completion of chemotherapy were included in the study. The children received two doses of intramuscular trivalent split influenza vaccine with 1 month apart in November-December 2003 (children <4 age 0.25 ml; >4 age 0.5 ml). Antibody titer was detected in the pre-vaccination and 4-week post-vaccination sera by hemagglutination inhibition (HI) method. Immune responses were measured as protective, geometric mean titers (GMT), and fourfold rises in HI titers.

RESULTS

We revealed that the post-vaccination GMT for each of the three antigens in patients with solid tumors has increased significantly (P < 0.05). A fourfold rise in the percentage of post-vaccination antibody titers has been detected as 84.4% for H(1)N(1), 77.8% for H(3)N(2), 60% for B. Stratification of patients as on active chemotherapy or being within 6 months of completion of chemotherapy in terms of fourfold rise in antibody titers exposed a statistically significant difference for only B (P = 0.34). Post-vaccination protective rates were between 86 and 97%.

CONCLUSIONS

Due to the interruptions in treatment caused by influenza infections, and economic benefits of the vaccine, we suggest that inactivated influenza vaccine should be applied as two doses annually in patients with solid tumor.

Immunisation practices of paediatric oncologists: an Australasian survey

AIM

The aim of this survey was to identify the current practices of paediatric oncologists in Australia and New Zealand regarding the immunisation of children treated for cancer.

METHODS

The survey was a nine-part questionnaire of current immunisation practices emailed to all paediatric oncologists practising in Australia (nine centres) and New Zealand (three centres) in June 2006.

RESULTS

Overall response rate was 82% (37 of 45 oncologists). Ninety-four per cent of respondents would recommend commencing 'booster' vaccinations at 6 months post completion of chemotherapy, in keeping with the current guidelines. Seventy-four per cent would recommend varicella vaccination. Intensity of the chemotherapy treatment was felt to be important, with 97% recommending re-immunising after a high-intensity regimen and only 48% after a lower-intensity regimen. Sixty-nine per cent stated they would recommend yearly influenza vaccinations for their patients.

CONCLUSION

This survey highlights the variability of practice in Australasia; for example, nearly one-third do not recommend yearly influenza vaccination for their patients. The level of chemotherapy intensity was an important factor for paediatric oncologists in determining whether 'booster' vaccinations were recommended. This is an important cancer survivorship issue and review of the evidence-base and implementation of these guidelines is required.

Cost-effectiveness of influenza vaccination in working-age cancer patients

BACKGROUND

Despite recommendations to immunize all patients at an increased risk of influenza complications, the vaccine utilization among high-risk nonelderly adults remains low and its cost-effectiveness is unclear. In the current study, the authors analyzed the cost-effectiveness of influenza vaccination in working-age (ages 20-64 years) cancer patients.

METHODS

The authors developed a decision-analytic model, from the societal perspective, using epidemiologic, vaccine effectiveness, resource utilization, cost, survival, and utility data from published sources, supplemented with data collected from the authors' own institutional accounting system. Two strategies were compared: influenza vaccination of working-age cancer patients and no vaccination. The base-case patient was assumed to be a 51-year-old cancer patient (the mean age for the National Cancer Institute's Surveillance, Epidemiology, and End Results [SEER] population of working-age patients within 5 years of cancer diagnosis).

RESULTS

The effectiveness of the influenza vaccine was 6.02 quality-adjusted life-years (QALYs) at a cost of $30.10. The effectiveness of the no vaccination strategy was 6.01 QALYs at a cost of $27.86. Compared with the no vaccination strategy, the incremental cost-effectiveness ratio of vaccinating working-age cancer patients would be $224.00 per QALY gained. Using the benchmark of $50,000 per QALY, the model was only sensitive to changes in cancer survival (threshold of 2.8 months).

CONCLUSIONS

The influenza vaccine is cost-effective for working-age cancer patients with a life expectancy of >or=3 months. All working-age cancer patients who are within 5 years of cancer diagnosis and have a life expectancy of at least 3 months should be vaccinated against influenza.

Influenza vaccination coverage among children with high-risk medical conditions

We evaluated influenza vaccination coverage in children with chronic disease at high risk of influenza complications, and the need for methods to increase parents' and pediatricians' knowledge of influenza and its prevention. The 5286 children aged less than 14 years attending our Emergency Department on Wednesdays and Sundays between 1 January and 30 April 2003 included 274 (5.2%) high-risk patients. The use of influenza vaccine during the previous three seasons had been very low, but significantly increased in the last season (2000-2001, 5.1%; 2001-2002, 12.9%; 2002-2003, 26.3%; p<0.001). The children with asthma or cardiac disease showed the lowest vaccination rates; their parents and primary care pediatricians had only a marginal knowledge of influenza and the benefits of its prevention. In conclusion, the delivery of influenza vaccine to children with chronic disease at high risk of influenza complications is completely inadequate, and major efforts are urgently needed to increase parents' and pediatricians' knowledge of its importance.

Immune response after influenza vaccination in children with cancer

PURPOSE

To assess the immune response to inactivated trivalent split influenza vaccine in children with cancer.

PROCEDURES

Forty-four children with various types of malignancies received two doses of influenza vaccine 2-4 weeks apart. Hemagglutinin-inhibition (HI) antibody titers were determined in paired sera obtained just before the first vaccination and 4 weeks after the second vaccination.

RESULTS

Influenza vaccine was administered to all children without any serious adverse effects. Protective titer rates (proportion of patients achieving antibody titers > or =40 among those with pre-vaccination titers <40) and response rates (proportion of patients with fourfold or more antibody rise) were 72% and 65% for H1N1, 60% and 40% for H3N2, and 38% and 46% for influenza B, respectively. However, patients on chemotherapy showed a significantly lower immune response to influenza A than those having completed chemotherapy; protection titer rates were 42% versus 90% for H1N1 (P = 0.006) and 25% versus 83% for H3N2 (P = 0.019). For influenza B, patients with low IgG showed a lower response rate than those with high IgG (29% vs. 61%, P = 0.040). Multivariate analysis revealed that factors significantly associated with a lower immune response were low IgG (P < 0.001) and administration of chemotherapy (P = 0.003) for H1N1, administration of chemotherapy (P = 0.008) for H3N2, and low white blood cell (WBC) count (P = 0.030) and low IgG (P = 0.030) for influenza B.

CONCLUSIONS

Influenza vaccination given to children with cancer was safe and induced immune reaction comparable to healthy children, although patients on chemotherapy and/or with chemotherapy-related conditions had a limited ability to produce a sufficient immune response.

Influenza immunisation in children with solid tumours

We assessed response to immunisation with trivalent split virus influenza vaccine in children with non-leukaemic malignant disease. Children with solid tumours and lymphoma received one or two doses of influenza vaccine, according to current UK guidelines, in autumn 2001 and/or 2002. Children were currently receiving chemotherapy or were within 6 months of completing chemotherapy. Pre and post vaccination sera were assessed for antibodies to the prevalent influenza strains by haemagglutination inhibition (HI). Sixty six children were assessed prior to 69 episodes of vaccination. In 30% episodes, children were susceptible to all three circulating influenza viruses (65% to H1N1, 42% to H3N2 and 90% to B) and only one patient showed protective titres (HI32) against all three strains. Seroresponse rates (4-fold rise in HI) for H1N1, H3N2 and B were 52%, 33% and 51% in 65 episodes. Following immunisation protective titres to all three viruses were seen in 25 episodes (38%) and protective responses to one or two viruses were seen in a further 12 (19%) episodes. There was no significant difference in response rates among children on treatment and off treatment and by intensity of chemotherapy. Children with solid tumours and lymphoma are highly susceptible to influenza infection. Influenza vaccine was well tolerated in this patient group and children showed a significant response to immunisation. These findings support the recommendation for annual influenza vaccination in these children.

Clinical and economic impact of influenza vaccination on healthy children aged 2-5 years

This paper reports the data concerning the net economic cost savings attributable to influenza vaccination in healthy children aged 2-5 years, and may be useful when deciding the best recommendations for the use of influenza vaccine in pediatrics. A total of 303 previously unprimed healthy children aged 2-5 years (163 males; mean age+/-S.D.: 3.22+/-2.43 years) were prospectively, blindly randomised in a 2:1 ratio to receive two doses of an inactivated, trivalent, virosome-formulated subunit influenza vaccine (Inflexal V, Berna Biotech, Berne, Switzerland) or no vaccination. The results show that influenza vaccination of healthy children aged 2-5 years substantially reduces influenza-like illnesses and related costs in the children themselves and their families. However, larger and longer running study spanning multiple seasons may be warranted before suggesting the universal vaccination of this group of subjects.

Pediatric influenza prevention and control

Global evaluation of influenza vaccination in children indicates that current recommendations are not followed. Most children at high risk for influenza-related complications do not receive the vaccine, and increased efforts are needed to protect them. Furthermore, immunizing healthy infants 6–23 months of age and their close contacts should be strongly encouraged. Vaccinations are recommended for children with recurrent acute otitis media or recurrent respiratory tract infections and possibly for healthy daycare and school-age children because of the potential socioeconomic implications of influenza. Issues that need to be addressed include educating physicians and parents concerning influenza-related illness and complications, cost-effectiveness and safety of licensed vaccines, adequate vaccine supply, and availability of intranasal products.

Are we ready for universal influenza vaccination in paediatrics?

Recent studies have suggested that paediatric influenza is a greater medical problem than usually thought because it can cause excess hospitalisations, medical visits, and antibiotic prescriptions even in healthy children, especially those under 2 years. Furthermore, influenza in otherwise healthy children may have substantial socioeconomic consequences for the children and their household contacts. These findings have led many experts to encourage the more widespread use of influenza vaccine in childhood. Although the immunogenicity of the available vaccines is good and they are safe, well-tolerated, and highly effective in preventing influenza and its complications, economic data support universal vaccination only when indirect effectiveness is considered. However, infants aged 6-23 months, children with recurrent acute otitis media or respiratory-tract infections, and healthy children attending day-care centres or elementary schools should be included among the paediatric groups requiring vaccination.

Immune responses to influenza immunization in children receiving maintenance chemotherapy for acute lymphoblastic leukemia

PURPOSE

To compare the immune responses to influenza vaccine in children with acute lymphoblastic leukemia (ALL) receiving maintenance chemotherapy with those in healthy children.

METHODS

Hemagglutinin-inhibition (HAI) antibody titers were determined before and after influenza vaccination in children with ALL and healthy controls. Immune responses were measured as geometric mean titers (GMT) and 4-fold rises in HAI titers.

RESULTS

Although post-immunization GMT were lower in children with ALL compared to healthy children for the H1N1 antigen (P<0.001), the H3N2 antigen (P=0.03), and for the influenza B antigen (P=0.003), at least 60% of children with ALL had at least a 4-fold rise in HAI titers to each of the influenza antigens.

CONCLUSIONS

While the GMT after trivalent influenza immunization in children with ALL were significantly lower than those seen in healthy children, the majority of children with ALL had 4-fold rises in HAI titers. Children receiving maintenance chemotherapy for ALL should receive yearly influenza vaccine.