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

Pediatric Clinical Influenza Disease by Type and Subtype 2015-2020: A Multicenter, Prospective Study

BACKGROUND

Previous investigations into clinical signs and symptoms associated with influenza types and subtypes have not definitively established differences in the clinical presentation or severity of influenza disease.

METHODS

The study population included children 0-17 years old enrolled at 8 New Vaccine Surveillance Network sites between 2015 and 2020 who tested positive for influenza virus by molecular testing. Demographic and clinical data were collected for study participants via parent/guardian interviews and medical chart reviews. Descriptive statistics were used to summarize demographic and clinical characteristics by influenza subtype. Multivariable logistic regression and Cox proportional hazard models were used to assess the effects of age, sex, influenza subtype, and history of asthma on severity, including hospital admission, need for supplemental oxygen, and length of stay.

RESULTS

Retractions, cyanosis, and the need for supplemental oxygen were more frequently observed among patients with influenza A(H1N1)pdm09. Headaches and sore throat were more commonly reported among patients with influenza B. Children with influenza A(H1N1)pdm09 and children with asthma had significantly increased odds of hospital admission (adjusted odds ratio [AOR]: 1.39, 95% confidence interval [CI]: 1.14-1.69; AOR: 2.14, 95% CI: 1.72-2.67, respectively). During admission, children with influenza A(H1N1)pdm09 had significantly increased use of supplemental oxygen compared to children with A(H3N2) (AOR: 0.60, 95% CI: 0.44-0.82) or B (AOR: 0.56, 95% CI: 0.41-0.76).

CONCLUSIONS

Among children presenting to the emergency department and admitted to the hospital, influenza A(H1N1)pdm09 caused more severe disease compared to influenza A(H3N2) and influenza B. Asthma also contributed to severe influenza disease regardless of subtype.

Congenital Heart Defects and Concurrent Diagnoses in Influenza Hospitalization in the Pediatric Health Information System Study, 2004-2019

Influenza is associated with adverse outcomes in children, although modification by additional medical conditions is not well-documented. We aimed to compare outcomes in children with versus without congenital heart defects (CHDs) who were hospitalized for influenza. We retrospectively evaluated patients 1-18y hospitalized for influenza in the Pediatric Health Information (PHIS) database from 2004 to 2019. Outcomes were compared by CHD presence and then by CHD severity (minor biventricular, major biventricular, and single ventricle disease) using log-binomial regression adjusted for propensity scores accounting for age at admission, sex, and history of asthma. Outcomes included inpatient mortality, intensive care unit (ICU) admission, mechanical ventilation, and length of stay (LOS) > 12 days. To evaluate for effect modification by genetic diagnoses, analyses were repeated stratified by CHD and genetic diagnosis. Among 55,161 children hospitalized for influenza, 2369 (4.3%) had CHDs, including 963 with minor biventricular, 938 with major biventricular, and 468 with single ventricle CHDs. Adjusting for propensity scores, children with CHDs had higher mortality (4.1% versus 0.9%) compared to those without CHDs (risk ratio [RR] 2.5, 95% confidence interval [CI] 1.9-3.4). Children with CHDs were at higher risk of mechanical ventilation (RR 1.6, 95% CI 1.6-1.7), ICU admission (RR 1.9, 95% CI 1.8-2.1), and LOS > 12 days (RR 2.2, 95% CI 2.0-2.3). Compared to those with neither CHD nor genetic condition, children with both had significantly higher risk of all outcomes, with the largest difference for LOS > 12 days (RR 2.3, 95% CI 2.0-2.7). Children with CHDs hospitalized for influenza are particularly susceptible to adverse outcomes compared to those without CHDs. Future studies are needed to corroborate findings in light of influenza vaccination.

Nudging towards COVID-19 and influenza vaccination uptake in medically at-risk children: EPIC study protocol of randomised controlled trials in Australian paediatric outpatient clinics

INTRODUCTION

Children with chronic medical diseases are at an unacceptable risk of hospitalisation and death from influenza and SARS-CoV-2 infections. Over the past two decades, behavioural scientists have learnt how to design non-coercive 'nudge' interventions to encourage positive health behaviours. Our study aims to evaluate the impact of multicomponent nudge interventions on the uptake of COVID-19 and influenza vaccines in medically at-risk children.

METHODS AND ANALYSES

Two separate randomised controlled trials (RCTs), each with 1038 children, will enrol a total of approximately 2076 children with chronic medical conditions who are attending tertiary hospitals in South Australia, Western Australia and Victoria. Participants will be randomly assigned (1:1) to the standard care or intervention group. The nudge intervention in each RCT will consist of three text message reminders with four behavioural nudges including (1) social norm messages, (2) different messengers through links to short educational videos from a paediatrician, medically at-risk child and parent and nurse, (3) a pledge to have their child or themselves vaccinated and (4) information salience through links to the current guidelines and vaccine safety information. The primary outcome is the proportion of medically at-risk children who receive at least one dose of vaccine within 3 months of randomisation. Logistic regression analysis will be performed to determine the effect of the intervention on the probability of vaccination uptake.

ETHICS AND DISSEMINATION

The protocol and study documents have been reviewed and approved by the Women's and Children's Health Network Human Research Ethics Committee (HREC/22/WCHN/2022/00082). The results will be published via peer-reviewed journals and presented at scientific meetings and public forums.

TRIAL REGISTRATION NUMBER

NCT05613751.

Trends in Outpatient Influenza Antiviral Use Among Children and Adolescents in the United States

BACKGROUND

Influenza antivirals improve outcomes in children with duration of symptoms <2 days and those at high risk for influenza complications. Real-world prescribing of influenza antivirals in the pediatric population is unknown.

METHODS

We performed a cross-sectional study of outpatient and emergency department prescription claims in individuals <18 years of age included in the IBM Marketscan Commercial Claims and Encounters Database between July 1, 2010 and June 30, 2019. Influenza antiviral use was defined as any dispensing of oseltamivir, baloxavir, or zanamivir. The primary outcome was the rate of antiviral dispensing per 1000 enrolled children. Secondary outcomes included antiviral dispensing per 1000 influenza diagnoses and inflation-adjusted costs of antiviral agents. Outcomes were calculated and stratified by age, acute versus prophylactic treatment, influenza season, and geographic region.

RESULTS

The analysis included 1 416 764 unique antiviral dispensings between 2010 and 2019. Oseltamivir was the most frequently prescribed antiviral (99.8%). Dispensing rates ranged from 4.4 to 48.6 per 1000 enrolled children. Treatment rates were highest among older children (12-17 years of age), during the 2017 to 2018 influenza season, and in the East South Central region. Guideline-concordant antiviral use among young children (<2 years of age) at a high risk of influenza complications was low (<40%). The inflation-adjusted cost for prescriptions was $208 458 979, and the median cost ranged from $111 to $151.

CONCLUSIONS

There is wide variability and underuse associated with influenza antiviral use in children. These findings reveal opportunities for improvement in the prevention and treatment of influenza in children.

Short Message Service Reminder Nudge for Parents and Influenza Vaccination Uptake in Children and Adolescents With Special Risk Medical Conditions: The Flutext-4U Randomized Clinical Trial

Importance

Children with chronic medical conditions are at increased risk of severe influenza. Uptake of influenza vaccination in children and adolescents with these identified special risk medical conditions (SRMCs) is suboptimal.

Objective

To assess the effectiveness of Flutext-4U, a parent short message service (SMS) reminder nudge intervention, in increasing influenza immunization in children and adolescents with SRMCs.

Design, Setting, and Participants

This randomized clinical trial was conducted at a tertiary pediatric hospital in Adelaide, South Australia, from April 15 to September 30, 2021. Children and adolescents aged 6 months to younger than 18 years with SRMCs and a subspecialist outpatient appointment over a 5-month period during the Australian seasonal influenza vaccination season (April-August 2021) were eligible to participate. Follow-up was until September 30, 2021.

Interventions

Participants were randomly assigned (1:1 ratio) to control: clinician nudges (hospital vaccine availability, ease of access, and recommendation from hospital subspecialists) or SMS intervention (control conditions plus an additional SMS reminder nudge to parents), with randomization stratified by age group (<5 years, 5-14 years, or >14 to <18 years).

Main Outcomes and Measures

The primary outcome was influenza vaccination, as confirmed by the Australian Immunisation Register.

Results

A total of 600 participants (intervention group: 298 [49.7%]; mean [SD] age, 11.5 [4.6] years; 162 female participants [54.4%]; control group: 302 [50.3%]; mean [SD] age, 11.4 [4.7] years; 155 female participants [51.3%]) were included. Influenza vaccination was 38.6% (113 of 293) in the SMS intervention group compared with 26.2% (79 of 302) in the control group (adjusted odds ratio [aOR], 1.79; 95% CI, 1.27-2.55; P = .001). Time to vaccine receipt was significantly lower among SMS participants (adjusted hazard ratio, 1.67; 95% CI, 1.25-2.22; P < .001). For participants randomly assigned by June 15, a significantly greater proportion receiving the SMS intervention were vaccinated during the optimal delivery period April to June 30 (SMS group: 40.0% [76 of 190] vs 25.4% [50 of 197]; aOR, 1.97; 95% CI, 1.28-3.06; P = .002).

Conclusions and Relevance

Results of this randomized clinical trial suggest that an additional SMS reminder nudge for parents delivered in the tertiary care hospital setting to children and adolescents with SMRCs resulted in higher influenza vaccine uptake compared with clinician nudges alone.

Trial Registration

ANZCTR Identifier: ACTRN12621000463875.

Guideline-Concordant Antiviral Treatment in Children at High Risk for Influenza Complications

BACKGROUND

National guidelines recommend antiviral treatment for children with influenza at high risk for complications regardless of symptom duration. Little is known about concordance of clinical practice with this recommendation.

METHODS

We performed a cross-sectional study of outpatient children (aged 1-18 years) at high risk for complications who were diagnosed with influenza during the 2016-2019 influenza seasons. High-risk status was determined using an existing definition that includes age, comorbidities, and residence in a long-term care facility. The primary outcome was influenza antiviral dispensing within 2 days of influenza diagnosis. We determined patient- and provider-level factors associated with guideline-concordant treatment using multivariable logistic regression.

RESULTS

Of the 274 213 children with influenza at high risk for influenza complications, 159 350 (58.1%) received antiviral treatment. Antiviral treatment was associated with the presence of asthma (aOR, 1.13; 95% confidence interval [CI], 1.11-1.16), immunosuppression (aOR, 1.10; 95% CI, 1.05-1.16), complex chronic conditions (aOR, 1.04; 95% CI, 1.01-1.07), and index encounter in the urgent care setting (aOR, 1.3; 95% CI, 1.26-1.34). Factors associated with decreased odds of antiviral treatment include age 2-5 years compared with 6-17 years (aOR, 0.95; 95% CI, .93-.97), residing in a chronic care facility (aOR, .61; 95% CI, .46-.81), and index encounter in an emergency department (aOR, 0.66; 95% CI, .63-.71).

CONCLUSIONS

Among children with influenza at high risk for complications, 42% did not receive guideline-concordant antiviral treatment. Further study is needed to elucidate barriers to appropriate use of antivirals in this vulnerable population.

Vaccine Preventable Diseases in Pediatric Palliative Care - A Multicenter Cross-Sectional Study

CONTEXT

Vaccine preventable diseases lead to distressful symptoms and complications among pediatric patients receiving specialized home palliative care. There was no data on the vaccination compliance.

OBJECTIVES

The objective was to determine the vaccination coverage, discuss the relevance of vaccinations and provide vaccination recommendations in pediatric palliative care.

METHODS

Vaccination data were compared in a multicenter cross-sectional study. Expert interviews were conducted to evaluate symptom burden. The vaccination status of patients treated by six German pediatric specialized home palliative care teams was recorded from January 2019 to December 2019. The data were compared to the national immunization schedule and the vaccination rate of a representative German pediatric cohort. Onset of missed vaccination was compared to the date of diagnosis of the life-limiting condition. A risk score was calculated to evaluate the relevance of each individual vaccinations.

RESULTS

Vaccination rates of Tdpa, haemophilus influenzae type B, poliomyelitis, hepatitis B, pneumococcal disease, meningococcal diseases type C, and MMR were lower compared to healthy controls. There were no significant differences in varicella. In most cases the discontinuation of recommended immunizations occurred after diagnosis of the palliative condition. Influenza had the highest risk score and was the most frequent vaccine preventable disease in retrospective data. This paper includes a pragmatic proposal for the management of vaccination in this vulnerable population.

CONCLUSION

Children and adolescents with life-limiting conditions are at increased risk of vaccine preventable diseases. Individual vaccination counselling is recommended.

Using provider-parent strategies to improve influenza vaccination in children and adolescents with special risk medical conditions: a randomised controlled trial protocol

INTRODUCTION

Influenza immunisation is a highly cost-effective public health intervention. Despite a comprehensive National Immunisation Program, influenza vaccination in children and adolescents with special risk medical conditions (SRMCs) is suboptimal. Flutext-4U is an innovative, multi-component strategy targeting paediatric hospitals, general practice and parents of children and adolescents with SRMC. The Flutext-4U study aims to assess the impact of Flutext-4U to increase influenza immunisation in children and adolescents with SRMC.

METHODS AND ANALYSIS

This is a randomised controlled trial involving parents of children and adolescents (aged >6 months to <18 years) with SRMC receiving tertiary care at the Women's and Children's Hospital (WCH), Adelaide, South Australia, who are eligible for funded influenza immunisation with a hospital appointment between the start of the seasonal influenza vaccination season and 31 July 2021, their treating general practitioners (GPs), and WCH paediatric specialists.Parents (of children/adolescents with SRMC) are randomised (1:1 ratio) to standard care plus intervention (SMS reminder messages to parents; reminders (written correspondence) for their child's GP from the hospital's Paediatric Outpatients Department) or standard care (hospital vaccine availability, ease of access and reminders for WCH subspecialists) with randomisation stratified by age-group (<5, 5-14, >14 to <18 years).The primary outcome is influenza vaccination, as confirmed by the Australian Immunisation Register.The proportion vaccinated (primary outcome) will be compared between randomised groups using logistic regression, with adjustment made for age group at randomisation. The effect of treatment will be described using an OR with a 95% CI.

ETHICS AND DISSEMINATION

The protocol and all study materials have been reviewed and approved by the Women's and Children's Health Network Human Research Ethics Committee (HREC/20/WCHN/5). Results will be disseminated via peer-reviewed publication and at scientific meetings, professional and public forums.

TRIAL REGISTRATION NUMBER

Australian New Zealand Clinical Trials Registry (ACTRN12621000463875).

The burden of hospital-attended influenza in Norwegian children

BACKGROUND

Norwegian health authorities do not recommend universal pediatric vaccination against seasonal influenza. We aimed to estimate the incidence of influenza by age and underlying medical conditions in hospitalized Norwegian children aged <18 years.

METHODS

Active surveillance for influenza in children <18 years was implemented in five hospitals during 2015-18. Children with respiratory symptoms and/or fever were prospectively enrolled and tested for influenza. Surveillance data were linked to health registry data to estimate the national burden of influenza in hospitals.

RESULTS

In 309 (10%) out of 3,010 hospital contacts, the child tested positive for influenza, corresponding to an average incidence of 0.96 hospital-attended influenza cases per 1,000 children <18 years of age. Children <1 year of age (3.8 per 1,000 children) and children with underlying medical conditions (17 per 1,000 children with bronchopulmonary dysplasia) had the highest average incidence. Among <1 year old children, 3% tested positive for influenza, compared to 25% for children aged 6-17. Few children were vaccinated against influenza.

CONCLUSIONS

Children <1 year of age and children with underlying medical conditions had a higher incidence of influenza requiring hospital treatment compared to the general population. Effective interventions against seasonal influenza for children in Norway should be considered.

Characteristics of children admitted to hospital with acute SARS-CoV-2 infection in Canada in 2020

Background:

Risk factors for severe outcomes of SARS-CoV-2 infection are not well established in children. We sought to describe pediatric hospital admissions associated with SARS-CoV-2 infection in Canada and identify risk factors for more severe disease.

Methods:

We conducted a national prospective study using the infrastructure of the Canadian Paediatric Surveillance Program (CPSP). Cases involving children who were admitted to hospital with microbiologically confirmed SARS-CoV-2 infection were reported from Apr. 8 to Dec. 31 2020, through weekly online questionnaires distributed to the CPSP network of more than 2800 pediatricians. We categorized hospital admissions as related to COVID-19, incidental, or for social or infection control reasons and determined risk factors for disease severity in hospital.

Results:

Among 264 hospital admissions involving children with SARS-CoV-2 infection during the 9-month study period, 150 (56.8%) admissions were related to COVID-19 and 100 (37.9%) were incidental infections (admissions for other reasons and found to be positive for SARS-CoV-2 on screening). Infants (37.3%) and adolescents (29.6%) represented most cases. Among hospital admissions related to COVID-19, 52 (34.7%) had critical disease, 42 (28.0%) of whom required any form of respiratory or hemodynamic support, and 59 (39.3%) had at least 1 underlying comorbidity. Children with obesity, chronic neurologic conditions or chronic lung disease other than asthma were more likely to have severe or critical COVID-19.

Interpretation:

Among children who were admitted to hospital with SARS-CoV-2 infection in Canada during the early COVID-19 pandemic period, incidental SARS-CoV-2 infection was common. In children admitted with acute COVID-19, obesity and neurologic and respiratory comorbidities were associated with more severe disease.

Risk factors in pediatric hospitalization for influenza A and B during the seven seasons immediately before the COVID-19 era in Japan

INTRODUCTION

The risk factors in pediatric influenza immediately before the COVID-19 era are not well understood. This study aims to evaluate the risk factors for hospitalization in pediatric influenza A and B for the recent seasons.

METHODS

Children with a fever of ≥38 °C and laboratory-confirmed influenza at 20 hospitals in outpatient settings in Japan in the 2013/14 to 2019/20 seasons were retrospectively reviewed. Possible risk factors, including gender, age, comorbidities, nursery school or kindergarten attendance, earlier diagnosis, no immunization, lower regional temperature, earlier season, and period of onset, were evaluated using binary logistic regression methods.

RESULTS

A total of 13,040 (type A, 8861; B, 4179) children were evaluated. Significant risk factors (p < 0.05) in multivariate analyses were young age, lower regional temperature, earlier season, respiratory illness (adjusted odds ratio [aOR]:2.76, 95% confidence interval [CI]:1.84-4.13), abnormal behavior and/or unusual speech (aOR:2.78, 95% CI:1.61-4.80), and seizures at onset (aOR:16.8, 95% CI:12.1-23.3) for influenza A; and young age, lower regional temperature, respiratory illness (aOR:1.99, 95% CI:1.00-3.95), history of febrile seizures (aOR:1.73, 95% CI:1.01-2.99), and seizures at onset (aOR:9.74, 95% CI:5.44-17.4) for influenza B.

CONCLUSIONS

In addition to previously known factors, including young age, seizures, and respiratory illness, abnormal behavior and/or unusual speech and lower regional temperature are new factors. Negative immunization status was not a risk factor for hospitalization. A better understanding of risk factors may help improve the determination of indications for hospitalization during the future co-circulation of influenza and COVID-19.

Behavior of hospitalized severe influenza cases according to the outcome variable in Catalonia, Spain, during the 2017-2018 season

Influenza is an important cause of severe illness and death among patients with underlying medical conditions and in the elderly. The aim of this study was to investigate factors associated with ICU admission and death in patients hospitalized with severe laboratory-confirmed influenza during the 2017–2018 season in Catalonia. An observational epidemiological case-to-case study was carried out. Reported cases of severe laboratory-confirmed influenza requiring hospitalization in 2017–2018 influenza season were included. Mixed-effects regression analysis was used to estimate the factors associated with ICU admission and death. A total of 1306 cases of hospitalized severe influenza cases were included, of whom 175 (13.4%) died and 217 (16.6%) were ICU admitted. Age 65–74 years and ≥ 75 years and having ≥ 2 comorbidities were positively associated with death (aOR 3.19; 95%CI 1.19–8.50, aOR 6.95, 95%CI 2.76–1.80 and aOR 1.99; 95%CI 1.12–3.52, respectively). Neuraminidase inhibitor treatment and pneumonia were negatively associated with death. The 65–74 years and ≥ 75 years age groups were negatively associated with ICU admission (aOR 0.41; 95%CI 0.23–0.74 and aOR 0.30; 95%CI 0.17–0.53, respectively). A factor positively associated with ICU admission was neuraminidase inhibitor treatment. Our results support the need to investigate the worst outcomes of hospitalized severe cases, distinguishing between death and ICU admission.

Key role of pediatricians and disease for influenza vaccination in children with high-risk chronic diseases

Annual influenza vaccination is recommended for children with chronic diseases. Studies on influenza vaccines, following controversies related to the 2009 H1N1 influenza, are scarce in Europe. Our aim was to evaluate the influenza vaccination coverage in such children in a French tertiary hospital. Secondary objectives were the evaluation of the influenza vaccination coverage trend and the identification of factors influencing the vaccination status. A prospective and descriptive study by questionnaire was performed at the end of 2017 in 402 French hospital outpatients with various underlying chronic diseases eligible to the influenza vaccination. The 2016-2017 vaccination coverage was 46.5%. Figures of 75% or greater were only found in patients with cystic fibrosis and sickle cell disease. CART analysis identified vaccination in the previous year, medical recommendation for vaccination, and maternal influenza vaccination as a child's decisive factors for being vaccinated.Conclusion: Influenza vaccination coverage remains insufficient in children receiving hospital follow-up for chronic diseases. Its implementation clearly depends on pediatricians' recommendation to vaccinate and on the type of chronic disease. What is Known: • Despite health policy recommendations, the rate of annual influenza vaccination in children with chronic diseases is low What is New: • Influenza vaccination coverage depends on the type of chronic disease and on the pediatricians' counseling to vaccine.

Multicenter Initial Guidance on Use of Antivirals for Children With Coronavirus Disease 2019/Severe Acute Respiratory Syndrome Coronavirus 2

BACKGROUND

Although coronavirus disease 2019 (COVID-19) is mild in nearly all children, a small proportion of pediatric patients develop severe or critical illness. Guidance is therefore needed regarding use of agents with potential activity against severe acute respiratory syndrome coronavirus 2 in pediatrics.

METHODS

A panel of pediatric infectious diseases physicians and pharmacists from 18 geographically diverse North American institutions was convened. Through a series of teleconferences and web-based surveys, a set of guidance statements was developed and refined based on review of best available evidence and expert opinion.

RESULTS

Given the typically mild course of pediatric COVID-19, supportive care alone is suggested for the overwhelming majority of cases. The panel suggests a decision-making framework for antiviral therapy that weighs risks and benefits based on disease severity as indicated by respiratory support needs, with consideration on a case-by-case basis of potential pediatric risk factors for disease progression. If an antiviral is used, the panel suggests remdesivir as the preferred agent. Hydroxychloroquine could be considered for patients who are not candidates for remdesivir or when remdesivir is not available. Antivirals should preferably be used as part of a clinical trial if available.

CONCLUSIONS

Antiviral therapy for COVID-19 is not necessary for the great majority of pediatric patients. For those rare cases of severe or critical disease, this guidance offers an approach for decision-making regarding antivirals, informed by available data. As evidence continues to evolve rapidly, the need for updates to the guidance is anticipated.

Multicenter Interim Guidance on Use of Antivirals for Children With Coronavirus Disease 2019/Severe Acute Respiratory Syndrome Coronavirus 2

BACKGROUND

Although coronavirus disease 2019 (COVID-19) is a mild infection in most children, a small proportion develop severe or critical illness. Data describing agents with potential antiviral activity continue to expand such that updated guidance is needed regarding use of these agents in children.

METHODS

A panel of pediatric infectious diseases physicians and pharmacists from 20 geographically diverse North American institutions was convened. Through a series of teleconferences and web-based surveys, a set of guidance statements was developed and refined based on review of the best available evidence and expert opinion.

RESULTS

Given the typically mild course of COVID-19 in children, supportive care alone is suggested for most cases. For children with severe illness, defined as a supplemental oxygen requirement without need for noninvasive or invasive mechanical ventilation or extracorporeal membrane oxygenation (ECMO), remdesivir is suggested, preferably as part of a clinical trial if available. Remdesivir should also be considered for critically ill children requiring invasive or noninvasive mechanical ventilation or ECMO. A duration of 5 days is appropriate for most patients. The panel recommends against the use of hydroxychloroquine or lopinavir-ritonavir (or other protease inhibitors) for COVID-19 in children.

CONCLUSIONS

Antiviral therapy for COVID-19 is not necessary for the great majority of pediatric patients. For children with severe or critical disease, this guidance offers an approach for decision-making regarding use of remdesivir.