American Academy of Pediatrics Committee on Infectious Diseases. Prevention of influenza: recommendations for influenza immunization of children, 2007-2008

Factors Influencing Health Equity of Influenza Vaccination in Pediatric Patients

Social factors can be a determinate for multiple health outcomes. We evaluated the association of numerous social factors on rates of influenza nonvaccination in a large pediatric primary and subspecialty care system.

The unattainable criteria for new infant vaccines

BACKGROUND

In 2013, the US Advisory Committee on Immunization Practices (ACIP) opted against adding meningococcal vaccines to the infant schedule due to poor cost-effectiveness. This raises a policy question: if meningococcal disease is too rare to justify routine vaccination, are there other vaccine-preventable causes of US infant deaths that could be supported?

METHODS

We tabulated US infant deaths from 2009-2013 using the CDC WONDER database. These causes of death were then categorized into one of 3 categories: 1) vaccine-preventable using currently available interventions; 2) potentially vaccine-preventable within the next 10 years; and 3) not preventable.

RESULTS

From 19.8 million births (3.9 million/year), ∼122,000 infants died (0.62%). Of these, 181 (0.15% of all deaths) were preventable using currently available vaccines, while an additional 779 were categorized as potentially preventable in the next 10 y. By exclusion, 121,040 (99.2%) were judged 'not vaccine-preventable'. Meningococcal deaths contributed at most 0.03% of all infant deaths, but accounted for 17-34% of current vaccine-preventable deaths.

CONCLUSIONS

The low number of vaccine-preventable deaths in the US makes it increasingly difficult to justify the introduction of any new infant vaccines.

Racial disparities in vaccination for seasonal influenza in early childhood

OBJECTIVES

Influenza vaccination is the best protection against infection and severe complications of disease, such as hospitalization and death. Therefore, it is important to accurately estimate vaccination coverage and to evaluate the role of race/ethnicity. This study examines racial disparities in influenza vaccination among children using a nationally representative sample.

STUDY DESIGN

This study used cross-sectional data from the 2009-2014 National Immunization Survey for children aged 19-35 months (n = 98,186) in the United States.

METHODS

The outcome variable was receipt of influenza vaccination (yes/no) and exposure variable was race/ethnicity. Weighted multivariate logistic regression was used to estimate the odds ratio and 95% confidence intervals (CIs) for the effect of race/ethnicity on receipt of the influenza vaccine.

RESULTS

The overall vaccination rates were 81.6% for non-Hispanic whites, 79.2% for Hispanics, 80.5% for non-Hispanic blacks, and 80.7% for non-Hispanic mixed/other. In the adjusted model, compared with non-Hispanic white children, Hispanic children were 13% less likely to receive influenza vaccination within the last 12 months (adjusted odds ratio [aOR] = 0.87; 95% CI: 0.80-0.94). In addition, children aged 24-29 months (aOR = 0.48; 95% CI: 0.44-0.52) and 30-35 months (aOR = 0.33; 95% CI: 0.30-0.36) were significantly less likely to receive influenza vaccination within the last 12 months compared with those who were 19-23 months old.

CONCLUSIONS

There were differences in influenza vaccination rates among different racial groups. Hispanic children had the lowest vaccination rates. Findings from our study have significant implications for targeted interventions to increase the overall vaccination rate for children in the United States.

Sterilizing immunity to influenza virus infection requires local antigen-specific T cell response in the lungs

Sterilizing immunity is a unique immune status, which prevents effective virus infection into the host. It is different from the immunity that allows infection but with subsequent successful eradication of the virus. Pre-infection induces sterilizing immunity to homologous influenza virus challenge in ferret. In our antigen-specific experimental system, mice pre-infected with PR8 influenza virus through nasal route are likewise resistant to reinfection of the same strain of virus. The virus is cleared before establishment of effective infection. Intramuscular influenza virus injection confers protection against re-infection with facilitated virus clearance but not sterilizing immunity. Pre-infection and intramuscular injection generates comparable innate immunity and antibody response, but only pre-infection induces virus receptor reduction and efficient antigen-specific T cell response in the lungs. Pre-infection with nH1N1 influenza virus induces virus receptor reduction but not PR8-specific T cell immune response in the lungs and cannot prevent infection of PR8 influenza virus. Pre-infection with PR8 virus induced PR8-specific T cell response in the lungs but cannot prevent infection of nH1N1 virus either. These results reveal that antigen-specific T cell immunity is required for sterilizing immunity.

Mothers' Employment Attributes and Use of Preventive Child Health Services

This study examines whether paid sick leave and hours worked per week are associated with receipt of recommended well-child visits, preventive dental care, influenza vaccines, obesity screening, and vision screening among U.S. children aged 0 to 17 years whose mothers were employed using data from the Medical Expenditure Panel Survey. Residual inclusion instrumental variables methods were used to address unobserved confounding related to maternal employment and child health care use. Instruments were the industry-specific mean of paid leave and hours worked. Fewer than half of children received the recommended number of well-child visits and dental care; only 14% of children received an influenza vaccine in the past year. Paid sick leave was associated with increased adherence to recommended well-child visits (marginal probability, 0.12; 95% confidence interval [CI] = 0.23, 0.01), preventive dental care (marginal probability, 0.28; 95% CI = 0.34, 0.33), and receipt of the influenza vaccine (marginal probability, 0.09; 95% CI = 0.13, 0.05 ).

Safety and Immunogenicity of Full-Dose Trivalent Inactivated Influenza Vaccine (TIV) Compared With Half-Dose TIV Administered to Children 6 Through 35 Months of Age

BACKGROUND

Children 6 through 35 months of age are recommended to receive half the dose of influenza vaccine compared with older children and adults.

METHODS

This was a 6-site, randomized 2:1, double-blind study comparing full-dose (0.5 mL) trivalent inactivated influenza vaccine (TIV) with half-dose (0.25 mL) TIV in children 6 through 35 months of age. Children previously immunized with influenza vaccine (primed cohort) received 1 dose, and those with no previous influenza immunizations (naive cohort) received 2 doses of TIV. Local and systemic adverse events were recorded. Sera were collected before immunization and 1 month after last dose of TIV. Hemagglutination inhibition antibody testing was performed.

RESULTS

Of the 243 subjects enrolled (32 primed, 211 naive), data for 232 were available for complete analysis. No significant differences in local or systemic reactions were observed. Few significant differences in immunogenicity to the 3 vaccine antigens were noted. The immune response to H1N1 was significantly higher in the full-dose group among primed subjects. In the naive cohort, the geometric mean titer for all 3 antigens after 2 doses of TIV were significantly higher in the 12 through 35 months compared with the 6 through 11 months age group.

CONCLUSIONS

Our study confirms the safety of full-dose TIV given to children 6 through 35 months of age. An increase in antibody responses after full- versus half-dose TIV was not observed, except for H1N1 in the primed group. Larger studies are needed to clarify the potential for improved immunogenicity with higher vaccine doses. Recommending the same dose could simplify the production, storage, and administration of influenza vaccines.

How we prevent and manage infection in sickle cell disease

Sickle cell disease (SCD) affects approximately 100,000 people in the US, 12,500 in the UK, and millions worldwide. SCD is typified by painful vaso-occlusive episodes, haemolytic anaemia and organ damage. A secondary complication is infection, which can be bacterial, fungal or viral. Universal newborn screening, routine use of penicillin prophylaxis, availability of conjugated vaccines against S. pneumoniae and comprehensive care programmes instituted during the past few decades in industrialized countries have dramatically reduced childhood mortality and improved life expectancy. Yet patients with SCD remain at increased risk of infection. Unfortunately, the treatment of most bacterial infections that are common in SCD is not based on the results of randomized controlled clinical trials. In their absence, treatment decisions are based on consensus guidelines, clinical experience or adapting treatment applied in other diseases. This leads to wide variation in treatment among institutions and even between treating physicians in a single institution. Prevention of infection, when possible, is most important and we focus on prevention through targeted prophylaxis and vaccination. We will share our management strategies for managing the more common infections in SCD and provide the rationale for our recommendations.

Surveillance for Healthcare-Acquired Febrile Respiratory Infection in Pediatric Hospitals Participating in the Canadian Nosocomial Infection Surveillance Program

Objective.

To determine the rates of healthcare-acquired febrile respiratory infection (HA-FRI) in Canadian pediatric hospitals and to determine the vaccination status of patients with healthcare-acquired respiratory syncytial virus (RSV) infection, influenza, or pneumococcal infection who were also eligible for immunoprophylaxis.

Methods.

Prospective surveillance was conducted in 8 hospitals from January 1 to April 30, 2005. All hospitalized patients less than 18 years of age were eligible, except for patients housed in standard newborn nurseries or psychiatric units. Infection control professionals reviewed laboratory reports, conducted ward rounds, and reviewed medical records to identify case patients. Descriptive analyses were completed, as well.

Results.

A total of 96 case patients were identified; 52 (54%) were male, and 48 (50%) were aged 1 year or less. Seventy-two patients (75%) had chronic medical conditions. Respiratory viruses accounted for 72 (71%) of 101 pathogens identified, and RSV was the virus most frequently identified. Of these 96 patients, 9 (9%) died, and 3 (3%) of the deaths were related to the patient's HA-FRI. The mean incidence rate was 0.97 infections/1,000 patient-days (range, 0.29–1.50 infections/1,000 patient-days). Only 2 (15%) of 13 influenza vaccine-eligible children who acquired influenza while hospitalized were reported to have been vaccinated, but influenza vaccination status was unknown for most children. However, 4 (80%) of 5 RSV prophylaxis-eligible children who had healthcare-acquired RSV infection had received immunoprophylaxis with anti-RSV monoclonal antibody.

Conclusions.

HA-FRI is mainly caused by viruses such as RSV, and it primarily affects children under 1 year of age and those with chronic medical conditions.

Administration time between seasonal live-attenuated influenza vaccine and trivalent influenza vaccine during the "Stop Flu at School" Campaign--Hawaii, 2009

OBJECTIVES

We determined whether the administration time differed between seasonal intranasal live-attenuated influenza vaccine (LAIV) and seasonal injectable trivalent inactivated influenza vaccine (TIV) during Hawaii's 2009 school-located influenza vaccination clinics. This information is useful for public health response and allows further investigation into possible differences between the two vaccines.

METHODS

We conducted a prospective cohort study in 15 public schools to determine mean times to administer LAIV and TIV to students. We performed group analyses to control for various clinic characteristics and conducted a stratified, weighted analysis.

RESULTS

A total of 4,701 students were enrolled in the study, and administration time was obtained for 3,869 (82%) students (1,492 [39%] LAIV and 2,377 [61%] TIV). The mean administration time for LAIV was 62 seconds and for TIV was 90 seconds, a difference of 28 seconds (p<0.01). This finding remained significant in the stratified analysis.

CONCLUSIONS

Although results indicated that both LAIV and TIV can be administered rapidly among school-aged populations, LAIV was faster to administer. This finding, in addition to the greater immunogenicity of LAIV compared with TIV among children, may be an important consideration for public health administrators in planning school-located mass vaccination clinics and encouraging patient acceptance of this vaccine.

Use of palivizumab in infants and young children with severe respiratory disease: a Delphi study

OBJECTIVE

To achieve a consensus of opinion among an expert group of pediatric pulmonologists regarding the appropriateness of the off-label use of palivizumab for some pediatric patients with severe respiratory diseases.

METHODS

A two-round modified Delphi technique was used. A 43-item self-administered questionnaire grouped into seven clinical scenarios was developed. Level of agreement for each statement was ranked on a 0-9 scale with 0 being total disagreement and 9 total agreement. Consensus was sought through the feedback of information and iteration. The final responses were evaluated for median and interquartile range to determine which questions the group had reached consensus about, either affirmatively or negatively.

RESULTS

Consensus was obtained for 24/43 statements (55.81%), including use of palivizumab for prevention of respiratory syncytial virus (RSV) infection in children with severe respiratory involvement due to neuromuscular disease, congenital or acquired immunodeficiency, storage disease, cystic fibrosis, diseases involving impaired ciliary clearance, patients operated on esophageal atresia and/or tracheoesophageal fistula, diaphragmatic hernia, bronchopulmonary malformations, severe tracheomalacia, lung transplant recipients and patients in the waiting list for lung transplant, patients oxygen-dependent for severe interstitial pulmonary disease and patients with severe pulmonary hypertension. Consensus against the use of palivizumab as prevention of RSV infection was also achieved in almost all the recurrent wheezing/asthma attacks situations.

CONCLUSION

A set of indication for off-label uses of palivizumab in pediatric pulmonology was developed in accordance with the degree of professional consensus on which they were based. The applicability of the present results to clinical practice should be evaluated individually and reviewed periodically in the light of new emerging evidence. Further studies are needed to add evidence to the most frequent and clinically oriented scenarios that have shown higher levels of uncertainty.

Myositis in a child with murine typhus

A 12-year-old boy presented with fever, lower extremity pain and weakness. Examination revealed paraparesis, thigh and calf tenderness. Labs showed high creatinine phosphokinase and Rickettsia typhi titers. This case illustrates endemic typhus should be considered in the differential diagnosis of myositis especially in areas with high prevalence of the disease. To our knowledge, this is the first reported case of myositis and paraparesis associated with a case of murine typhus.

Implementing and sustaining school-located influenza vaccination programs: perspectives from five diverse school districts

Local health departments have typically led school-located influenza vaccination (SLIV) programs, assuming resource-intensive roles in design, coordination, and vaccination. This level of involvement is often not financially sustainable over time. Five diverse school districts in Los Angeles County designed, implemented, refined, and institutionalized their own SLIV programs over 3 years by identifying and maximizing their existing resources. School district nurses and other staff served as project leaders, designing their own vaccination administration process, parental consent, and clinic promotional models. Two districts expanded their existing school immunization clinics and three developed their vaccination capacity with community partnerships. Each district tailored its program in creative resource-minimum ways, sometimes abandoning or adopting new methods/technologies based on the effectiveness in previous seasons. The shared experiences and strategies between district nurses and the local health department described in this article illustrate a district's ability to develop a tailor-made SLIV program, often in less than ideal conditions.

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.

Healthcare workers and H1N1 vaccination: does having a chronic disease make a difference?

Introduction

A novel H1N1 vaccine was manufactured in response to the pandemic in 2009. This study describes the willingness to be vaccinated for H1N1 among healthcare workers (HCWs) in primary healthcare clinics with and without chronic medical conditions, their reasons for refusing vaccination and whether they sought additional information to make an informed decision for the vaccination.

Materials and methods

An anonymous survey was conducted in November 2009 among all medical, nursing, allied health and operations HCWs in nine primary care clinics in Singapore. Participants were asked if they had any chronic medical conditions associated with influenza-related complications (example: asthma, stroke, heart disease, cancer, diabetes mellitus, renal disease), their perception towards vaccination for H1N1 and against seasonal influenza within the preceding 2 years.

Results

The initial response rate was 80%, of which 711 (54.7%) of the completed surveys were analysed. Among the 711 respondents, 16.6% reported having at least 1 chronic disease. Asthma (10.8%), hypertension (10.4%) and dyslipidaemia (9.8%) were the main chronic conditions. Only 39.4% of respondents were willing to be vaccinated against H1N1. Males were 2.07 (95% CI 1.19–3.62) times more likely than females to receive the H1N1 vaccination; the 45–54 and 55+ years old were 2.12 (95% CI 1.06–4.24) and 2.44 (95% CI 1.13–5.27) times more willing than those below 25 years old; and those who considered accepting the seasonal influenza vaccine were 7.0 times more likely than those who did not (95%CI 4.48–10.92). The 2 principal barriers were “fear of side effects” and “unsure of vaccine's effectiveness”. Although 78% attended some H1N1-related talks, only 7% of all HCWs felt that they had sufficient information. Most wanted more information about the vaccine's safety profile and contraindications.

Conclusion

Fewer than 40% of HCWs expressed willingness to receive the H1N1 vaccination, lower than past rates of influenza vaccine. HCWs in primary care clinics who had a chronic condition did not perceive themselves to be at higher risk of developing H1N1-related complications and were not more willing than the rest of the HCWs to accept H1N1 vaccination. Vaccine's side effects and effectiveness were the main concerns. Uptake of H1N1 vaccine may improve with targeted health information covering the vaccine's safety profile.

Severe influenza cases in paediatric intensive care units in Germany during the pre-pandemic seasons 2005 to 2008

BACKGROUND

Data on complications in children with seasonal influenza virus infection are limited. We initiated a nation-wide three-year surveillance of children who were admitted to a paediatric intensive care unit (PICU) with severe seasonal influenza.

METHODS

From October 2005 to July 2008, active surveillance was performed using an established reporting system for rare diseases (ESPED) including all paediatric hospitals in Germany. Cases to be reported were hospitalized children < 17 years of age with laboratory-confirmed influenza treated in a PICU or dying in hospital.

RESULTS

Twenty severe influenza-associated cases were reported from 14 PICUs during three pre-pandemic influenza seasons (2005-2008). The median age of the patients (12 males/8 females) was 7.5 years (range 0.1-15 years). None had received vaccination against influenza. In 14 (70%) patients, the infection had been caused by influenza A and in five (25%) by influenza B; in one child (5%) the influenza type was not reported. Patients spent a median of 19 (IQR 12-38) days in the hospital and a median of 11 days (IQR 6-18 days) in the PICU; 10 (50%) needed mechanical ventilation. Most frequent diagnoses were influenza-associated pneumonia (60%), bronchitis/bronchiolitis (30%), encephalitis/encephalopathy (25%), secondary bacterial pneumonia (25%), and ARDS (25%). Eleven (55%) children had chronic underlying medical conditions, including 8 (40%) with chronic pulmonary diseases. Two influenza A- associated deaths were reported: i) an 8-year old boy with pneumococcal encephalopathy following influenza infection died from cerebral edema, ii) a 14-year-old boy with asthma bronchiale, cardiac malformation and Addison's disease died from cardiac and respiratory failure. For nine (45%) patients, possibly permanent sequelae were reported (3 neurological, 3 pulmonary, 3 other sequelae).

CONCLUSIONS

Influenza-associated pneumonia and secondary bacterial infections are relevant complications of seasonal influenza in Germany. The incidence of severe influenza cases in PICUs was relatively low. This may be either due to the weak to moderate seasonal influenza activity during the years 2005 to 2008 or due to under-diagnosis of influenza by physicians. Fifty% of the observed severe cases might have been prevented by following the recommendations for vaccination of risk groups in Germany.

Intramuscular immunization of mice with live influenza virus is more immunogenic and offers greater protection than immunization with inactivated virus

BACKGROUND

Influenza virus continues to cause significant hospitalization rates in infants and young children. A 2-dose regime of trivalent inactivated vaccine is required to generate protective levels of hemagglutination inhibiting (HAI) antibodies. A vaccine preparation with enhanced immunogenicity is therefore desirable.

METHODS

Mice were inoculated intramuscularly (IM) with live and inactivated preparations of A/Wisconsin/67/2005 (H3N2). Serum cytokine levels, hemagglutinin (HA)-specific antibody responses and nucleoprotein (NP)-specific CD8+ T cell responses were compared between vaccinated groups, as well as to responses measured after intranasal infection. The protective efficacy of each vaccine type was compared by measuring virus titers in the lungs and weight loss of mice challenged intranasally with a heterosubtypic virus, A/PR/8/34 (H1N1).

RESULTS

Intramuscular administration of live virus resulted in greater amounts of IFN-α, IL-12 and IFN-γ, HA-specific antibodies, and virus-specific CD8+ T cells, than IM immunization with inactivated virus. These increases corresponded with the live virus vaccinated group having significantly less weight loss and less virus in the lungs on day 7 following challenge with a sublethal dose of a heterosubtypic virus.

CONCLUSIONS

Inflammatory cytokines, antibody titers to HA and CD8+ T cell responses were greater to live than inactivated virus delivered IM. These increased responses correlated with greater protection against heterosubtypic virus challenge, suggesting that intramuscular immunization with live influenza virus may be a practical means to increase vaccine immunogenicity and to broaden protection in pediatric populations.

Influenza vaccine coverage among children under the age of 5 years in Poland during 2004-2008

Introduction

Influenza is a considerable health problem all over the world. The most important group for influenza vaccination are children: the highest attack rate during community out-breaks of influenza can be found among school-aged children or their family members; children bear a considerable risk for complications due to influenza, leading to an increased need for healthcare resources (including hospitalization). The high level of vaccine coverage among school children could provide protection against influenza among households and could reduce mortality rates among older individuals.

Objective

The aim of this study was to estimate the influenza vaccine coverage among children younger than 5 years and to find any trends in influenza vaccine coverage in 2004-2008 in Poland.

Material and methods

Official data (number of administrated vaccines and the age of vaccinated individuals) collected by the National Institute of Hygiene, the National Institute of Public Health, and the Central Statistical Office in Poland were analyzed. This data are reported by physicians and collected from reports prepared annually by the Sanitary-Epidemiological Stations at a local level. The vaccine coverage rate was calculated as a percentage of vaccinated individuals among all children under the age of 5 years.

Results

The influenza vaccine coverage among children younger than 5 years varied from 1% (2007 and 2008) to 1.9% (2005). The proportion of vaccinated children aged less than 5 compared with the total number of flu shots administrated irrespective of age also varied from 1.4% (2007) to 2% (2005).

Conclusions

The influenza vaccination coverage among Polish children aged less than 5 years is low and has persisted at the same level. More educational activities directed both to patients (parents) and healthcare workers would be needed to improve a general knowledge about influenza vaccination benefits among young children.

We should not be complacent about our population-based public health response to the first influenza pandemic of the 21st century

Background

More than a year after an influenza pandemic was declared in June 2009, the World Health Organization declared the pandemic to be over. Evaluations of the pandemic response are beginning to appear in the public domain.

Discussion

We argue that, despite the enormous effort made to control the pandemic, it is now time to acknowledge that many of the population-based public health interventions may not have been well considered. Prior to the pandemic, there was limited scientific evidence to support border control measures. In particular no border screening measures would have detected prodromal or asymptomatic infections, and asymptomatic infections with pandemic influenza were common. School closures, when they were partial or of short duration, would not have interrupted spread of the virus in school-aged children, the group with the highest rate of infection worldwide. In most countries where they were available, neuraminidase inhibitors were not distributed quickly enough to have had an effect at the population level, although they will have benefited individuals, and prophylaxis within closed communities will have been effective. A pandemic specific vaccine will have protected the people who received it, although in most countries only a small minority was vaccinated, and often a small minority of those most at risk. The pandemic vaccine was generally not available early enough to have influenced the shape of the first pandemic wave and it is likely that any future pandemic vaccine manufactured using current technology will also be available too late, at least in one hemisphere.

Summary

Border screening, school closure, widespread anti-viral prophylaxis and a pandemic-specific vaccine were unlikely to have been effective during a pandemic which was less severe than anticipated in the pandemic plans of many countries. These were cornerstones of the population-based public health response. Similar responses would be even less likely to be effective in a more severe pandemic. We agree with the recommendation from the World Health Organisation that pandemic preparedness plans need review.

Antivirals for influenza: strategies for use in pediatrics

Influenza infection is annually responsible for significant morbidity and mortality, particularly among the very young and old. Recently updated guidelines recommend influenza vaccination of all children aged 6 months to 18 years; however, childhood vaccination remains underutilized. Furthermore, concerns over the reduced efficacy of vaccination in children have further heightened the need for effective treatment schemes. Antiviral therapies have emerged as attractive options in the battle against influenza infection. These agents include the adamantanes (amantadine and rimantadine) and neuraminidase inhibitors (zanamivir, oseltamivir, and peramivir). Broad-scale use of adamantane antivirals has been severely limited in recent years because of high resistance rates and their inability to cover influenza type B. Neuraminidase inhibitors cover influenza types A and B, and have been promulgated to first-line therapy because of historically low resistance rates and relatively infrequent side effects. Moreover, these agents are effective options in combating non-seasonal influenza strains, including H5N1 and pandemic 2009 H1N1. Oseltamivir may be particularly appealing for treating children since it is available in multiple oral dosage formulations, whereas commercially available zanamivir use is limited in young children because it requires inhalation. However, the emergence of resistance to oseltamivir among influenza A strains may limit its usefulness. Additional concerns with neuraminidase inhibitor use in pediatrics center around emerging reports, primarily from Japan, that have temporally linked oseltamivir to significant neuropsychiatric events in children of varying ages. Numerous novel antiviral agents are under development, but most are far from market approval. In addition to treating and preventing the initial burden of pediatric influenza infection, antiviral therapies may significantly reduce secondary bacterial infections (including pneumonia and otitis media), unnecessary antibiotic prescribing, and healthcare-associated costs.

Analyses of the specificity of CD4 T cells during the primary immune response to influenza virus reveals dramatic MHC-linked asymmetries in reactivity to individual viral proteins

Influenza is a contagious, acute respiratory disease that is a major cause of morbidity and mortality throughout the world. CD4 T cells play an important role in the immune response to this pathogen through the secretion of antiviral cytokines, and by providing help to CD8 T cells and B cells to promote the development of immunological memory and neutralizing antibody responses. Despite these well-defined roles in the anti-influenza response, our understanding of CD4 T-cell diversity and specificity remains limited. In the study reported here, overlapping peptides representing 5 different influenza viral proteins were used in EliSpot assays to enumerate and identify the specificity of anti-influenza CD4 T cells directly ex vivo following infection of mice with influenza virus, using two strains that express unrelated MHC class II molecules. These experiments evaluated whether the reactivity of CD4 T cells generally tracked with particular influenza proteins, or whether MHC preferences were the predominant factor dictating anti-CD4 T-cell specificity in the primary immune response. We made the unexpected discovery that the distribution of CD4 T-cell specificities for different influenza proteins varied significantly depending on the single class II molecule expressed in vivo. In SJL mice, the majority of epitopes were specific for the HA protein, while the NP protein dominated the response in C57BL/10 mice. Given the diversity of human MHC class II molecules, these findings have important implications for the ability to rationally design a vaccine that will generate a specific CD4 T-cell immune response that is effective across diverse human populations.

Statewide school-located influenza vaccination program for children 5-13 years of age, Hawaii, USA

Nearly half of students in participating elementary and middle schools were vaccinated during 2007–2008.

New guidance recommends annual influenza vaccination for all children 5–18 years of age in the United States. During 2007–2008, Hawaii offered inactivated and live attenuated influenza vaccine at school-located clinics for grades kindergarten through 8. Most (90%) public and private schools participated, and 622 clinics were conducted at 340 schools. Of 132,775 children 5–13 years of age, 60,760 (46%) were vaccinated. The proportion vaccinated peaked at 54% for those 6 years of age and declined for older cohorts. More than 90% of schoolchildren transited the clinic in <10 minutes. A total of 16,920 staff-hours were expended; estimated cost per dose administered was $27 and included vaccine purchase and administration, health staffing resources, printing costs, data management, and promotion. This program demonstrates the feasibility of conducting mass school-located influenza vaccination programs in public and private schools statewide, as might be indicated to respond to pandemic influenza.

Asthma prevalence and exacerbations in children: is there an association with childhood vaccination?

Infections and vaccinations may have a potential role in the normal maturation of the immune system, in the development and balance of regulatory pathways, and in the development and exacerbations of asthma. Asthma exacerbations often result from respiratory viral infections, and, while vaccination towards common viral infections may reduce the occurrence of such exacerbations, there has been concern that vaccinations can increase the risk of asthma. Current studies show that childhood vaccines, including inactivated influenza vaccine, are generally safe. However, there is some concern regarding possible exacerbations in infants or children with frequent wheezing or persistent asthma who are given live-attenuated influenza vaccination. Although severe allergic adverse events attributable to vaccination are extremely rare, all serious allergic reactions should be further assessed to detect the likely causative vaccine component, such as egg protein or gelatin. The risks of not vaccinating children far outweigh the risks of allergy and asthma exacerbations. Therefore, childhood vaccination should remain an essential part of child health programs and should not be withheld, even from children with asthma or those predisposed to allergy.

Influenza virus infection in infants less than three months of age

OBJECTIVE

We evaluated the presentation, outcomes, and the risk of serious bacterial infection (SBI) in infants <3 months old with influenza virus infection.

PATIENTS AND METHODS

We identified demographic, hospitalization, and microbiologic data from computerized medical records for all infants and children <24 months of age, with laboratory confirmed influenza infection cared for at a tertiary care children's hospital during 4 winter seasons (2004-2008). We compared those <3 months of age with older groups.

RESULTS

We identified 833 children <24 months of age with laboratory-confirmed influenza. Of those, 218 were <3 months old. Influenza accounted for 3.6% of all evaluations of febrile infants and 12% of febrile infant encounters during winter. Infants <3 months of age were less likely to have a high risk chronic medical condition, but were more likely to be hospitalized than children 3 to <24 months old (P < 0.005). Infants <3 months with influenza had fewer prolonged hospital stays than those 3 to <6 months old [P = 0.056; OR: 0.5 (0.24-1.0)] and 6 to <12 months old [P = 0.011; OR: 0.43 (0.24-0.83)]. Five (2.3%) infants <3 months old had SBI.

CONCLUSIONS

Infants <3 months of age with influenza virus infection often present with fever alone. Although they are more likely to be hospitalized than those 3 to <24 months old, hospital stays are short and outcomes generally good. Infants with influenza virus infection have a low risk of concomitant SBI.

A novel influenza A (H1N1) vaccine in various age groups

BACKGROUND

There is an urgent need for a vaccine that is effective against the 2009 pandemic influenza A (H1N1) virus.

METHODS

A split-virus, inactivated candidate vaccine against the 2009 H1N1 virus was manufactured, and we evaluated its safety and immunogenicity in a randomized clinical trial. Subjects were between 3 and 77 years of age, stratified into four age groups. The immunization schedule consisted of two vaccinations, 21 days apart. Subjects were injected with placebo or with vaccine, with or without alum adjuvant, at doses of 7.5 microg, 15 microg, or 30 microg. Serologic analysis was performed at baseline and on days 21 and 35.

RESULTS

A total of 2200 subjects received one dose, and 2103 (95.6%) received the second dose, of vaccine or placebo. No severe adverse side effects associated with the vaccine were noted. In the nonadjuvanted-vaccine groups, injection-site or systemic reactions, most mild in nature, were noted in 5.5 to 15.9% of subjects. Among the subjects receiving 15 microg of nonadjuvanted vaccine, a hemagglutination-inhibition titer of 1:40 or more was achieved by day 21 in 74.5% of subjects between 3 and 11 years of age, 97.1% of subjects between 12 and 17 years, 97.1% of subjects between 18 and 60 years, and 79.1% of subjects 61 years of age or older; by day 35, the titer had been achieved in 98.1%, 100%, 97.1%, and 93.3% of subjects, respectively. The proportion with a titer of 1:40 or more was generally highest among the subjects receiving 30 microg of vaccine, with or without adjuvant. Vaccine without adjuvant was associated with fewer local reactions and greater immune responses than was vaccine with adjuvant.

CONCLUSIONS

These data suggest that a single dose of 15 microg of hemagglutinin antigen without alum adjuvant induces a typically protective immune response in the majority of subjects between 12 and 60 years of age. Lesser immune responses were seen after a single dose of vaccine in younger and older subjects. (ClinicalTrials.gov number, NCT00975572).

Impact of influenza-like illness and effectiveness of influenza vaccination in oncohematological children who have completed cancer therapy

In order to evaluate the impact of influenza-like illness and the effectiveness of influenza vaccination in children with oncohematological disease who have completed cancer therapy, 182 children with a diagnosis of oncohematological disease were divided into two subgroups on the basis of the length of time off therapy (<6 months or 6-24 months) and randomised 1:1 to receive influenza vaccination or not. The controls were 91 otherwise healthy children unvaccinated against influenza. The results show that the clinical and socioeconomic impact of influenza-like illnesses and the effectiveness of influenza vaccination in oncohematological children who have completed cancer therapy are related to the length of the off therapy period, and seem to be significantly greater in those who have been off therapy for less than 6 months in comparison with healthy controls. This suggests that the administration of influenza vaccination should be strongly recommended only among oncohematological children who have been off therapy for less than 6 months.

Egg allergy in childhood: an update

PURPOSE OF REVIEW

Allergy to hen's egg is common in infancy and childhood. The management of egg allergy involves dietary avoidance of egg-containing foods, implementation of anaphylaxis precautions and ongoing monitoring for tolerance development. In this article, we review the recent literature regarding the immunology, clinical presentation, diagnosis, management and natural history of egg allergy.

RECENT FINDINGS

Retrospective studies suggest that most egg-allergic children will become tolerant over time. Regular ingestion of small quantities of cooked egg in baked products is often well tolerated and may hasten tolerance development. Influenza vaccination of egg-allergic patients remains controversial, and immunization of patients with previous significant reactions or anaphylaxis to egg is currently not recommended. In recent years, there has been increasing success in clinical trials of specific oral tolerance induction to egg, but concerns regarding the safety and long-term efficacy still preclude the use of oral immunotherapy in clinical practice.

SUMMARY

Egg allergy generally has a good prognosis. Despite recent advances in oral immunotherapy trials, the treatment of egg allergy currently relies on avoidance of egg-containing foods until tolerance has developed. It remains unclear whether the ongoing low-dose exposure to egg proteins in cooked foods improves the natural history of egg allergy.

Influenza vaccination coverage among Spanish children, 2006

OBJECTIVES

Traditionally, influenza is not considered to be a serious disease in healthy children. However, for vulnerable populations, such as young children and those with chronic medical conditions, influenza can lead to serious complications and even death. This study aimed to assess vaccination coverage among Spanish children under 16 years of age in 2006, and to describe the factors associated with vaccination.

STUDY DESIGN

Cross-sectional survey.

METHODS

In total, 8851 records of children included in the Spanish National Health Survey for 2006 were analysed. The reply ('yes' or 'no') to the question: 'Did you have a flu shot in the latest campaign?' was used as a dependent variable. Influenza vaccine coverage was calculated as the percentage of individuals aged 6 months to 16 years whose parents reported that they had been vaccinated against influenza in the most recent campaign. The influence of sociodemographic variables on vaccination and the presence of associated chronic diseases (asthma and/or diabetes) were also analysed.

RESULTS

Vaccination coverage among Spanish children in 2006 was 6.82%: 19.43% in children with associated conditions (asthma and/or diabetes), and 5.81% in healthy children. The only factor significantly associated with influenza vaccination in children with associated conditions was household income; children with a lower household monthly income were more likely to have been vaccinated against influenza than children with a higher household monthly income (odds ratio 1.96). In children for whom vaccination is not indicated, the probability of being vaccinated against influenza was greater in those whose parents were not university graduates.

CONCLUSION

Influenza vaccination coverage in Spanish children is low. Socio-economic inequalities continue to be a factor at the time of vaccination.

Sepsis in the neonate

In the neonatal intensive care unit, critical care nurses who are not advanced practice nurses cannot make the medical diagnosis of infection/sepsis in the neonate. Even so, the critical care nurse has a critical role in dealing with sepsis infection. The nurse must (1) have a high index of suspicion about the risk of infection, (2) be able to recognize septic/infected newborns, (3) report related concerns to the physician or advanced practice nurse, and (4) advocate on behalf of the infant to ensure a timely diagnostic workup and empiric antibiotics. This article is a guide for understanding issues related to sepsis in the neonatal intensive care unit.

Increasing influenza vaccination coverage in recommended population groups in Europe

The clinical and economic burden of seasonal influenza is frequently underestimated. The cornerstone of controlling and preventing influenza is vaccination. National and international guidelines aim to implement immunization programs and targeted vaccination-coverage rates, which should help to enhance the vaccine uptake, especially in the at-risk population. This review purposes to highlight the vaccination guidelines and the actual vaccination situation in four target groups (the elderly, people with underlying chronic conditions, healthcare workers and children) from a European point of view.

Update on universal childhood immunizations

PURPOSE OF REVIEW

To provide an update of research findings and recommendations regarding immunizations.

RECENT FINDINGS

New research has examined the efficacy of the 2007-2008 influenza vaccine, the transmission and incidence of human papillomavirus, the increased prevalence of pneumococcal serotypes not included in the 7-valent pneumococcal conjugate vaccine, the emergence of a drug-resistant strain of Streptococcus pneumoniae, febrile seizure rates following measles-mumps-rubella-varicella vaccination, and the 2006 mumps outbreak in the American Midwest. The Food and Drug Administration has approved the expansion of live attenuated influenza virus vaccine and quadrivalent meningococcal conjugate vaccine for use in children no younger than 2 years of age. The Advisory Committee on Immunization Practices now recommends immunization with quadrivalent meningococcal conjugate vaccine for all previously unvaccinated 11-18-year-old children and has revised its recommendations for Streptococcus pneumoniae catch-up vaccinations. The Advisory Committee on Immunization Practices no longer expresses a preference for the use of the combination measles-mumps-rubella-varicella vaccine over separate measles-mumps-rubella and varicella administration. Because of a notable recall of Haemophilus influenzae type B vaccines by Merck & Co Inc, Whitehouse Station, New Jersey, USA, the Advisory Committee on Immunization Practices recommends that pediatric providers conserve available Haemophilus influenzae type B vaccines by delaying the administration of the booster dose of the vaccine in healthy children.

SUMMARY

New vaccine recommendations continue to be made, and research continues on infectious diseases, vaccine safety, and vaccine efficacy.