Severe complications in influenza-like illnesses

Effectiveness of cocoon strategy vaccination on prevention of influenza-like illness in young infants

During the initial half-year of their existence, infants cannot receive the influenza vaccine, yet they face the greatest susceptibility to severe influenza complications. In this study, we seek to determine whether influenza vaccination of maternal and household contacts is associated with a reduced risk of influenza-like illness (ILI) and severe acute respiratory infection (SARI) in infants. This work was prospectively conducted during the influenza season. A total of 206 infants were included in this study. The percentage of infants with only the mother vaccinated is 12.6% (n:26), and the percent of infants with all household contacts vaccinated is 16% (n:33). Among the infants with only the mother vaccinated, the effectiveness of influenza vaccine is estimated as 35.3% for ILI and 41.3% for SARI. Among infants with all household contacts vaccinated, the effectiveness is estimated as 48.9% for ILI and 76.9% for SARI. Based on the results of multivariate logistic regression analysis, all-household vaccination is a protective factor against SARI (OR: 0.07 95% CI [0.01-0.56]), household size (OR: 1.75, 95% CI [1.24-2.48]) and presence of secondhand smoke (OR: 2.2, 95% CI [1.12-4.45]) significant risk factors for SARI in infants. The mother alone being vaccinated is not a statistically significant protective factor against ILI (OR: 0.46, 95% CI [0.19-1.18]) or SARI (OR: 0.3, 95% CI [0.11-1.21]). Along with the obtained results and analysis, this study provides clear evidence that influenza vaccination of all household contacts of infants aged 0-6 months is significantly associated with protecting infants from both ILI and SARI.

ADLM Guidance Document on Laboratory Diagnosis of Respiratory Viruses

Respiratory viral infections are among the most frequent infections experienced worldwide. The COVID-19 pandemic has highlighted the need for testing and currently several tests are available for the detection of a wide range of viruses. These tests vary widely in terms of the number of viral pathogens included, viral markers targeted, regulatory status, and turnaround time to results, as well as their analytical and clinical performance. Given these many variables, selection and interpretation of testing requires thoughtful consideration. The current guidance document is the authors' expert opinion based on the preponderance of available evidence to address key questions related to best practices for laboratory diagnosis of respiratory viral infections including who to test, when to test, and what tests to use. An algorithm is proposed to help laboratories decide on the most appropriate tests to use for the diagnosis of respiratory viral infections.

Complications of Influenza A or B Virus Infection in Individuals With SCN1A-Positive Dravet Syndrome

BACKGROUND AND OBJECTIVES

To determine the frequency and spectrum of complications of influenza infection in individuals with SCN1A-positive Dravet syndrome (SCN1A-DS).

METHODS

Individuals with SCN1A-DS were identified in neurologists' care at 2 hospitals in Melbourne, Australia, with additional searches of EEG databases, the Victorian PAEDS FluCan influenza database, and the University of Melbourne Epilepsy Genetics Research Program database. Medical records were searched and families questioned to identify individuals who had an influenza infection; reported infections were confirmed by pathology report. For these individuals, we obtained baseline clinical characteristics and clinical details of the influenza infection.

RESULTS

Twenty-one of 82 individuals (26%) had 24 documented influenza infections (17 influenza A and 7 influenza B) at age 0.5-25 years (median 4 years). All presented to hospital, 18/24 (75%) for status epilepticus or seizure exacerbations. Recovery was prompt in 18/24 (75%) infections, delayed but complete in 1/24 (4%) and incomplete in 5/24 (21%). One child died from influenza pneumonia, and long-term neurologic sequelae were seen with 4 infections. These individuals were poorly responsive after termination of status epilepticus. Brain imaging in 2 showed cerebral edema and 1 also having imaging features of laminar necrosis. All have ongoing neurologic deficits compared with their baseline, 1 having profound global impairment.

DISCUSSION

Our data show that patients with SCN1A-DS are highly susceptible to neurologic complications during and severe sequelae after influenza infection, including moderate to severe persistent neurologic impairments and death. Safe administration of the seasonal influenza vaccine should be prioritized for this population.

An Eight-Year Profile of Children with Influenza A(H1N1) in a Large Hospital in India

As influenza virus A(H1N1) continues to circulate, reports from India have documented mainly respiratory involvement in children. This retrospective chart review of children at a medical college found that from August 2009 to July 2017, 855 children aged 3 months to 15 years had H1N1 influenza of whom 310 (36.3%) were admitted and 29 (9.4% admissions) died. In 2009-12, 76.5% patients presented in August-October but from 2015 to 2017, 89.3% came in January-March. The proportion of under-fives increased from 54.0% in 2009-10 to 77.7% in 2015-17. Among admitted children, 82.6% were under 5 years, 96.1% had respiratory symptoms and 11% had seizures. Six children had encephalopathy of whom four died; two survivors had severe neurological sequelae. Other features included gastroenteritis, otitis media, myositis and hepatitis. Complications included shock (10.7%) and acute respiratory distress syndrome (6.1%). Evidence of bacterial/fungal infection was present in 71 (22.9%). Oxygen was required by 123 children (39.7%), high-dependency/intensive care by 47 (15.2%), 17 (5.5%) received high-flow oxygen and 29 (9.4%) required mechanical ventilation. There were no significantly increased odds of needing intensive care or of dying in children with underlying diseases or among different age groups but those with underlying central nervous system (CNS) diseases had higher odds of needing high-dependency/intensive care [odds ratio (OR) 2.35, p = 0.046]. Significantly, children with CNS symptoms had nearly seven times higher odds of needing mechanical ventilation (OR 6.85, p < 0.001) and over three times higher odds of dying (OR 3.31, p = 0.009). Lay summaryH1N1 Influenza ("swine flu") emerged as a global pandemic in 2009 and continues to affect children all over the world. This review of records from a medical college hospital in southern India found that 855 children aged 3 months to 15 years came with H1N1 influenza over 8 years from August 2009 to July 2017. In 2009-12, over three-quarters of them presented in the rainy season but from 2015-17, almost 90% came in the winter and spring, suggesting a change in the seasonality of the outbreaks, which could impact the choice of dates for annual influenza vaccination. The proportion under 5 years of age increased from 54% in 2009-10 to 78% in 2015-17, suggesting possible immunity in children exposed to earlier outbreaks. Over a third of the children needed admission of whom almost 40% needed oxygen, one-sixth needed high-dependency/intensive care and 1 in 11 admitted children died, emphasizing the severity of this disease. While most children had respiratory symptoms, all organs of the body were affected; 11% of those admitted had seizures and 6 had encephalitis. Children admitted with central nervous system symptoms had an almost 7-fold higher risk of needing high-dependency/intensive care and an over 3-fold higher risk of dying.

Hospital utilization rates for influenza and RSV: a novel approach and critical assessment

BACKGROUND

Influenza and respiratory syncytial virus (RSV) contribute significantly to the burden of acute lower respiratory infection (ALRI) inpatient care, but heterogeneous coding practices and availability of inpatient data make it difficult to estimate global hospital utilization for either disease based on coded diagnoses alone.

METHODS

This study estimates rates of influenza and RSV hospitalization by calculating the proportion of ALRI due to influenza and RSV and applying this proportion to inpatient admissions with ALRI coded as primary diagnosis. Proportions of ALRI attributed to influenza and RSV were extracted from a meta-analysis of 360 total sources describing inpatient hospital admissions which were input to a Bayesian mixed effects model over age with random effects over location. Results of this model were applied to inpatient admission datasets for 44 countries to produce rates of hospital utilization for influenza and RSV respectively, and rates were compared to raw coded admissions for each disease.

RESULTS

For most age groups, these methods estimated a higher national admission rate than the rate of directly coded influenza or RSV admissions in the same inpatient sources. In many inpatient sources, International Classification of Disease (ICD) coding detail was insufficient to estimate RSV burden directly. The influenza inpatient burden estimates in older adults appear to be substantially underestimated using this method on primary diagnoses alone. Application of the mixed effects model reduced heterogeneity between countries in influenza and RSV which was biased by coding practices and between-country variation.

CONCLUSIONS

This new method presents the opportunity of estimating hospital utilization rates for influenza and RSV using a wide range of clinical databases. Estimates generally seem promising for influenza and RSV associated hospitalization, but influenza estimates from primary diagnosis seem highly underestimated among older adults. Considerable heterogeneity remains between countries in ALRI coding (i.e., primary vs non-primary cause), and in the age profile of proportion positive for influenza and RSV across studies. While this analysis is interesting because of its wide data utilization and applicability in locations without laboratory-confirmed admission data, understanding the sources of variability and data quality will be essential in future applications of these methods.

The burden of influenza and other respiratory viruses in hospitalized infants and children in a university hospital, Jordan

Background

Acute lower respiratory infection (ALRI) is a major cause of morbidity and mortality worldwide in young children and is predominately caused by viral respiratory pathogens. This study aims to identify the viral etiologies of ALRI in hospitalized children in Jordan University Hospital and compare the clinical characteristics of influenza virus infection with other respiratory viruses.

Methods

A retrospective viral surveillance study that included 152 children below 15 years of age admitted with ALRI from December 2018 through April 2019 was conducted. We recorded results of real-time reverse transcriptasepolymerase chain reaction (RT-PCR) for common respiratory viruses. Clinical and demographic information of the study population was collected from patients' electronic medical records.

Results

152 patients were identified with a median age of 1 year (mean was 2.1 years). Ninety-five patients (62.5%) were males. One or more viral respiratory pathogens were detected in 145 (95.3%) children. Respiratory syncytial virus was the most detected virus in 68 patients (44.8%). Influenza virus was detected in 25 patients (16.4%). Children with influenza infection had more fever and lower leukocyte count compared to children infected with other viruses. The severity of the ALRI correlated significantly with several factors, including age less than six months and the presence of neuromuscular disease (p<0.05).

Conclusion

Viral detection was common among children admitted with ALRI. Viruses, including influenza, are recognized as significant contributors to the morbidity associated with ALRI. More attention is needed on strategies for the prevention and detection of viral ALRI in developing countries.

The Effect of the COVID-19 Pandemic on Childhood Immunizations: Ways to Strengthen Routine Vaccination

Primary care providers play key roles in ensuring that children and the community receive vaccines on time. Sometimes, this role includes the task of reassuring parents who are vaccine hesitant that vaccines are safe and effective. Now, because of coronavirus disease 2019 (COVID-19), providers are presented with the additional challenge of maintaining and strengthening routine vaccination during a pandemic. As COVID-19 cases increased and states implemented stay-at-home orders, outpatient visits declined significantly. As a result, childhood immunization rates also declined. Increasing communication efforts regarding the importance of vaccination will be worthwhile, as the effect of the COVID-19 pandemic has highlighted the threat of an infectious disease and has increased awareness of the vaccine development process. Prior to 2020, many parents had not seen the devastating consequences of an infectious disease. The pandemic may change a parent's perspective, particularly as it relates to the influenza vaccine. Providers should continue to promote the importance of well-child and vaccination visits. [Pediatr Ann. 2020;49(12):e516-e522.].

Neurologic Complications in Children Hospitalized With Influenza Infections: Prevalence, Risk Factors and Impact on Disease Severity

BACKGROUND

Influenza infection is a common cause of respiratory disease and hospitalization in children. Neurologic manifestations of the infection have been increasingly reported and may have an impact on the severity of the disease. The aim of this study is to describe neurologic events in pediatric patients hospitalized with influenza and identify associated risk factors.

METHODS

Retrospective cohort study which included all hospitalized patients with microbiologic confirmation of influenza disease over 4 epidemic seasons, focusing on neurologic complications. Demographic, laboratory and clinical data, as well as past history, were recorded. Descriptive and analytic statistical study was performed using SPSS and R statistical software.

RESULTS

Two hundred forty-five patients were included. Median age was 21 months (interquartile range, 6-57) and 47.8% had a previous underlying condition. Oseltamivir was administered to 86% of patients, median hospitalization was 4 days (interquartile range, 3-6), and pediatric intensive care unit admission rate 8.9%. Twenty-nine patients (11.8%) developed neurologic events, febrile seizures being the most frequent, followed by nonfebrile seizures and encephalopathy. Status epilepticus occurred in 4 children, and 69.6% of seizures recurred. Patients with a previous underlying condition were at greater risk of developing a neurologic complication [odds ratio (OR), 4.55; confidence interval (CI), 95% 1.23-16.81). Male sex (OR, 3.21; CI 95%, 1.22-8.33), influenza B virus (OR, 2.82; CI 95%, 1.14-7.14) and neurologic events (OR, 3.34; CI 95%, 1.10-10.19) were found to be risk factors for pediatric intensive care unit admission.

CONCLUSIONS

A significant proportion of influenza-related hospitalized patients develop neurologic complications, especially seizures which may be prolonged or recurrent. Previous underlying conditions pose the greatest risk to neurologic events, which increase disease severity.

Vaccine hesitancy and influenza beliefs among parents of children requiring a second dose of influenza vaccine in a season: An American Academy of Pediatrics (AAP) Pediatric Research in Office Settings (PROS) study

To receive adequate protection against influenza, some children 6 months through 8 y old need two doses of influenza vaccine in a given season. Currently, only half of those receiving the first dose receive a second. Our objective was to assess vaccine hesitancy and influenza disease and vaccine knowledge, attitudes, and beliefs among caregivers of children who received the first of their two needed doses. As part of a national-randomized control trial of second dose text-message influenza vaccine reminders (2017-2018 season), a telephone survey collected caregiver and index child demographic information. Each child had received the first of two needed influenza vaccine doses. Caregivers completed a measure of general vaccine hesitancy - the five-question Parent Attitudes About Childhood Vaccines Survey Tool (PACV-5) - and questions about influenza infection and vaccine. We assessed associations between participant demographic characteristics, vaccine hesitancy, and influenza beliefs and calculated the standardized proportion of caregivers endorsing each outcome using logistic regression. Analyses included responses from 256 participants from 36 primary care practices in 24 states. Some caregivers (11.7%) reported moderate/high vaccine hesitancy and many had misperceptions about influenza disease and vaccine. In multivariable models, no single variable was consistently associated with inaccurate knowledge, attitudes, and beliefs. These results demonstrate that caregivers whose children received the first dose of influenza vaccine may still be vaccine hesitant and have inaccurate influenza beliefs. Pediatricians should consider broadly addressing inaccurate beliefs and promoting vaccination even after caregivers agree to the first dose.

Age-Stratified Risk of Critical Illness in Young Children Presenting to the Emergency Department with Suspected Influenza

OBJECTIVE

To investigate the risk of critical illness by age group among young children without a chronic condition presenting to the emergency department (ED) with suspected influenza.

STUDY DESIGN

Retrospective study of patients aged <2 years presenting to the ED with suspected influenza (defined by diagnostic codes for influenza or influenza-like illness) from 2009 to 2017 in 49 hospitals in the Pediatric Health Information System. Patients with chronic conditions were excluded. The main clinical outcomes were intensive care unit (ICU) admission, ventilatory support, vasopressor administration, and mortality, which were compared independently by age group (<3 months, 3 to <6 months, 6 to <12 months, and 12 to <24 months). To compare outcomes by age, we estimated the prevalence of each outcome by age group after fitting logistic regression models to control for demographic differences between groups.

RESULTS

A total of 55 986 children were studied. Overall admission and ICU admission rates were 20% and 2%, respectively. After adjustment for demographic variables, infants aged <3 months had higher rates of ICU admission (2.7%; 95% CI, 2.0%-3.3%; P < .001 compared with other age groups) and ventilatory support (2.5%; 95% CI, 1.9%-3.2%; P < .001 compared with other age groups); however, there were no differences in vasopressor administration. The overall case fatality rate was low (0.007%) and thus could not be compared across age groups.

CONCLUSIONS

Infants aged <3 months with suspected influenza are at greatest risk for critical illness. Although critical illness is uncommon, these findings should be incorporated into acute management decisions, including the need for specified outpatient follow-up or hospitalization, and public health efforts should focus on prevention and disease-modifying interventions in this high-risk population.

Vaccination against Paediatric Respiratory Pathogens

Acute respiratory infections (ARIs) are extremely common in children, especially those under 5 years old. They can lead to complications, super-infection, respiratory failure, and even compromised respiratory function in adulthood. For some of the responsible pathogens, vaccines are available. This review reports current issues about vaccines against the main respiratory pathogens to highlight the available strategies to reduce the burden of paediatric respiratory disease. The optimal use of influenza, pneumococcal, pertussis and measles vaccines is required in order to reduce ARI burden. Vaccination coverage rates must be improved to achieve the full benefits of these vaccines. Recently, advances in the knowledge of respiratory syncytial virus structural biology and immunology as well as the development of new techniques to generate vaccine candidates have increased the number of promising vaccines even against this harmful pathogen.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Pandemic 2009 influenza A (H1N1)-associated deaths among children in China: A retrospective analysis

Importance

A cluster of influenza-associated deaths occurred among children during pandemic 2009 influenza A (H1N1) in China, but the risk factors and causes for death have not been clarified.

Objective

We describe the clinical findings regarding 2009 influenza A (H1N1)-associated pediatric deaths in China, including the risk factors for death.

Methods

The definition of 2009 influenza A (H1N1)-associated pediatric death is death in a child who is younger than 14 years and has laboratory-confirmed influenza. We collected data of total 810 hospitalized patients with 2009 influenza A (H1N1) infection from September 2009 to February 2010 in 17 hospitals across China. The clinical characteristics, laboratory abnormalities, and treatment course were retrospectively studied.

Results

Of the 810 patients hospitalized with 2009 influenza A (H1N1) infection, 19 (2.3%) died. Ten patients died from severe pneumonia and acute respiratory distress syndrome; eight died from encephalopathy/encephalitis; one died from secondary fungal meningitis. Patients who died were more likely than patients who survived to have neutrophilia, lymphopenia, elevated C-reactive protein, and elevations of lactate dehydrogenase, creatine kinase, creatine kinase-MB, aspartate aminotransferase and alanine aminotransferase. There were no significant differences in the median age, median time from onset of illness to admission, underlying chronic disease, and initiation of antiviral therapy within 48 hours of illness onset, between patients who died and those who survived.

Interpretation

The risk factors for pediatric death associated with 2009 influenza A (H1N1) infection are different from those of seasonal influenza. The most common causes of death are viral pneumonia, acute respiratory distress syndrome, and encephalopathy/encephalitis.

Influenza-Associated Pediatric Deaths in the United States, 2010-2016

BACKGROUND

Influenza-associated pediatric deaths became a notifiable condition in the United States in 2004.

METHODS

We analyzed deaths in children aged <18 years with laboratory-confirmed influenza virus infection reported to the Centers for Disease Control and Prevention during the 2010-2011 to 2015-2016 influenza seasons. Data were collected with a standard case report form that included demographics, medical conditions, and clinical diagnoses.

RESULTS

Overall, 675 deaths were reported. The median age was 6 years (interquartile range: 2-12). The average annual incidence was 0.15 per 100 000 children (95% confidence interval: 0.14-0.16) and was highest among children aged <6 months (incidence: 0.66; 95% confidence interval: 0.53-0.82), followed by children aged 6-23 months (incidence: 0.33; 95% confidence interval: 0.27-0.39). Only 31% (n = 149 of 477) of children aged ≥6 months had received any influenza vaccination. Overall, 65% (n = 410 of 628) of children died within 7 days after symptom onset. Half of the children (n = 327 of 654) had no preexisting medical conditions. Compared with children with preexisting medical conditions, children with none were younger (median: 5 vs 8 years old), less vaccinated (27% vs 36%), more likely to die before hospital admission (77% vs 48%), and had a shorter illness duration (4 vs 7 days; P < .05 for all).

CONCLUSIONS

Each year, influenza-associated pediatric deaths are reported. Young children have the highest death rates, especially infants aged <6 months. Increasing vaccination among children, pregnant women, and caregivers of infants may reduce influenza-associated pediatric deaths.

Influenza

Influenza is an acute respiratory illness, caused by influenza A, B, and C viruses, that occurs in local outbreaks or seasonal epidemics. Clinical illness follows a short incubation period and presentation ranges from asymptomatic to fulminant, depending on the characteristics of both the virus and the individual host. Influenza A viruses can also cause sporadic infections or spread worldwide in a pandemic when novel strains emerge in the human population from an animal host. New approaches to influenza prevention and treatment for management of both seasonal influenza epidemics and pandemics are desirable. In this Seminar, we discuss the clinical presentation, transmission, diagnosis, management, and prevention of seasonal influenza infection. We also review the animal-human interface of influenza, with a focus on current pandemic threats.

Influenza in children

PURPOSE OF REVIEW

We review the current information and evidence available on the global burden of disease in the pediatric population, clinical presentation and complications, testing, treatment, and immunization.

RECENT FINDINGS

In addition to multiple other risk factors for influenza complications, children with neurologic and neuromuscular disorders are significantly higher risk for serious complications. In practice, there is no lower age limit for children with influenza who can be treated with oseltamivir. The quadrivalent live attenuated influenza vaccine was not recommended for use during the 2016-2017 season due to poor effectiveness.

SUMMARY

Influenza infection causes a significant burden of disease each year in the pediatric population worldwide. Both healthy and chronically ill children can fall prey to complications either due to the virus itself or secondary bacterial infection. Children within high-risk groups should be tested and treated with neuraminidase inhibitors. Immunization against influenza is well tolerated and effective.

Detection of viral respiratory pathogens in mild and severe acute respiratory infections in Singapore

To investigate the performance of laboratory methods and clinical case definitions in detecting the viral pathogens for acute respiratory infections (ARIs) from a prospective community cohort and hospital inpatients, nasopharyngeal swabs from cohort members reporting ARIs (community-ARI) and inpatients admitted with ARIs (inpatient-ARI) were tested by Singleplex Real Time-Polymerase Chain Reaction (SRT-PCR), multiplex RT-PCR (MRT-PCR) and pathogen-chip system (PathChip) between April 2012 and December 2013. Community-ARI and inpatient-ARI was also combined with mild and severe cases of influenza from a historical prospective study as mild-ARI and severe-ARI respectively to evaluate the performance of clinical case definitions. We analysed 130 community-ARI and 140 inpatient-ARI episodes (5 inpatient-ARI excluded because multiple pathogens were detected), involving 138 and 207 samples respectively. Detection by PCR declined with days post-onset for influenza virus; decrease was faster for community-ARI than for inpatient-ARI. No such patterns were observed for non-influenza respiratory virus infections. PathChip added substantially to viruses detected for community-ARI only. Clinical case definitions discriminated influenza from other mild-ARI but performed poorly for severe-ARI and for older participants. Rational strategies for diagnosis and surveillance of influenza and other respiratory virus must acknowledge the differences between ARIs presenting in community and hospital settings.

Does the Influenza Vaccine Prevent Sequelae Such as Myocarditis from Developing?

Vaccination continues to be a valuable and simple procedure to guard patients from an illness that may prevent them from completing their normal everyday tasks, missing days of work, and even lead to unnecessary sequelae. The following case describes one of the many complications that are seen on a regular basis in any community hospital in different regions of the world. The objective of this publication is to remind the public and practitioner of the urgency to vaccinate each season; thereby, curbing the virus's ability to mutate and preventing unwanted consequences such as bacterial super infection or myocarditis.

Economic analysis of rapid and sensitive polymerase chain reaction testing in the emergency department for influenza infections in children

BACKGROUND

Rapid multiplex polymerase chain reaction (PCR) assays simultaneously detect several respiratory viral pathogens with high sensitivity. Maximizing detection of influenza at the point of care has the potential to reduce unnecessary antibiotic use, laboratory tests and hospitalizations. However, the cost-effectiveness of rapid multiplex PCR assays for influenza has not been compared with other diagnostic methods in children.

METHODS

For children presenting to the emergency department with influenza-like illness, we compared costs and outcomes using 4 different testing strategies for detection of influenza: (1) a rapid multiplex PCR platform (FilmArray); (2) traditional PCR; (3) direct-fluorescent antibody and (4) rapid antigen tests. Costs were assessed from the hospital perspective, and effectiveness was defined as quality-adjusted life years (QALYs). Input parameters were obtained from previous studies, and the model was run separately for children aged 3-36 months and 3-18 years.

RESULTS

Rapid multiplex PCR testing was the most effective testing strategy for children in both age groups. The incremental cost-effectiveness when compared with rapid antigen tests was $115,556 per QALY for children aged 3-36 months and from $228,000 per QALY for children aged 3-18 years. The cost-effectiveness of rapid multiplex PCR was sensitive to estimates for influenza prevalence, the proportion of patients treated with antivirals and the cost per test.

CONCLUSIONS

Our model identifies scenarios in which identification of influenza in the emergency department using rapid multiplex PCR testing is a cost-effective strategy for infants and children 3 months through 18 years. Including detection of other respiratory viruses in the analysis would further improve cost-effectiveness.

Influenza vaccination in pediatric age

To increase the protective efficacy against influenza in pediatric populations, several attempts to modify the composition or the route of administration of an inactivated influenza vaccine have been made. Adjuvants have been added, vaccines with higher antigen content have been developed and intradermal administration of inactivated influenza vaccine with a variety of devices has been considered. Such attempts to develop universal influenza vaccines will continue to be made. For some time, the knowledge that the licensed influenza vaccines induce strain-specific immunity and may have low efficacy in unexpected outbreaks of new epidemic strains has motivated the development of preparations with broader and longer-lasting protection. Ideally, children would be included early in the evaluation of the efficacy of new vaccines to avoid lengthy delays in making the protection available to this vulnerable population. Moreover, further studies to clarify definitively whether protection of infants <6 months of age can be obtained through vaccination of the pregnant woman have to be performed.