COMMITTEE ON INFECTIOUS DISEASES. Recommendations for Prevention and Control of Influenza in Children, 2021-2022

Impact of obstructive sleep apnea on clinical outcomes of hospitalization due to influenza in children: A propensity score-matched analysis of the US Nationwide Inpatient Sample 2005-2018

BACKGROUND

Previous studies have explored the association between obstructive sleep apnea (OSA) and clinical outcomes of influenza in adults, whereas limited research examined this relationship in pediatric populations. This study aimed to evaluate the clinical impact of OSA on the outcomes of pediatric influenza hospitalizations.

METHODS

This was a population-based, retrospective study. Data of children aged 1-19 years hospitalized for influenza infection were extracted from the United States (US) Nationwide Inpatient Sample Database 2005-2018. Univariable and multivariable regression analyses determined associations between OSA, length of stay (LOS), total hospital costs, pneumonia, and life-threatening events.

RESULTS

After propensity-score matching, a total of 2100 children were analyzed. The logistic analysis revealed that children with OSA had a significantly increased LOS (β = 2.29 days; 95% confidence interval, CI: 1.01-3.57, p < .001) and total hospital costs (β = 26.06 thousand dollars; 95% CI: 6.62-45.51, p = .009), and higher odds of pneumonia (aged 6-10 years: odds ratio [OR] = 1.52; 95% CI: 1.01-2.27, p = .043; aged ≥ 11 years: OR = 1.83; 95% CI: 1.33-2.53, p < .001).

CONCLUSIONS

During influenza admissions, children with OSA had longer LOS, higher hospital costs, and an increased risk of pneumonia compared to those without OSA. These findings underscore the importance of recognizing and managing OSA in influenza-related infections among children.

A Retrospective Report on Simple Febrile Seizure Management in a Pediatric Emergency Department

OBJECTIVE

To determine whether pediatric emergency medicine physicians are compliant with the 9-year-old simple febrile seizure guideline created by the American Academy of Pediatrics (AAP).

METHODS

A retrospective chart review of patients, ages 6 to 60 months, who presented to the emergency department between May 2011 and December 2019. Key variables abstracted were urine, blood, nasal viral swab, and radiographic results.

RESULTS

The retrospective cohort of 285 children met inclusion criteria. Among 285 children, 342 studies were performed with a median of 1.2 studies per patient. There were 77 urine cultures obtained with 6 bacterial pathogens. Nasal viral swabs were performed on 65 children with 9 positive results. Blood cultures were obtained for 28 children and none were positive. Chest radiographs were performed on 37 children with 4 showing pneumonia.

CONCLUSION

The study results reflect areas of opportunity to update guidelines with a focus to consider obtaining urine studies, viral sampling, and chest x-rays.

Clinical Outcomes of Children With COVID-19 by SARS-CoV-2 Strain: A Cohort Study

OBJECTIVE

We sought to investigate the disease outcomes and predictors of severe outcomes among children infected with the Delta variant of SARS-CoV-2 compared with pre-Delta strains.

METHODS

Single-center retrospective cohort study in an emergency department located within an urban academic children's hospital. Patients included children (0-18 years) who tested positive for SARS-CoV-2. Main outcomes measured include need for hospital admission or COVID-directed therapies.

RESULTS

There was a trend toward decreased hospital admission and no significant difference in the severity of outcomes in the Delta cohort relative to the pre-Delta cohort. The Delta cohort had lower odds of hospital admission (odds ratio [OR], 0.79; 95% confidence interval [CI], 0.51-1.23), but the result was not statistically significant. Logistic regression analyses showed that overall, age 1 to 4 years (OR, 2.35; 95% CI, 1.23-4.57) and public insurance (OR, 1.80, 95% CI, 1.08-3.01) were predictors of hospital admission. Within the Delta cohort, the presence of any comorbidity increased the odds of admission (OR, 2.52; 95% CI, 1.09-6.04). Black children had lower odds of admission than white children (overall OR, 0.53; 95% CI, 0.31-0.90; pre-Delta OR, 0.50; 95% CI, 0.26-0.95).

CONCLUSIONS

The severity of measured disease outcomes was similar in pediatric patients when comparing children infected with the pre-Delta and Delta variants of SARS-CoV-2, even among children with comorbidities once adjusting for acuity.Ongoing research is essential to determine disease severity and risk for children with comorbidities because SARS-CoV-2 continues to mutate, including with Omicron subvariants.

Optimal timing of influenza vaccination in young children: population based cohort study

OBJECTIVE

To assess optimal timing of influenza vaccination in young children.

DESIGN

Population based cohort study.

SETTING

United States.

PARTICIPANTS

Commercially insured children aged 2-5 years who were vaccinated against influenza during 2011-18.

MAIN OUTCOME MEASURE

Rates of diagnosis of influenza among children who were vaccinated against influenza, by birth month.

RESULTS

Overall, 819 223 children aged 2-5 received influenza vaccination. Children vaccinated in November and December were least likely to have a diagnosis of influenza, a finding that may be confounded by unmeasured factors that influence the timing of vaccination and risk of influenza. Vaccination commonly occurred on days of preventive care visits and during birth months. Children born in October were disproportionately vaccinated in October and were, on average, vaccinated later than children born in August and earlier than those born in December. Children born in October had the lowest rate of influenza diagnosis (for example, 2.7% (6016/224 540) versus 3.0% (6462/212 622) for those born in August; adjusted odds ratio 0.88, 95% confidence interval 0.85 to 0.92).

CONCLUSIONS

In a quasi-experimental analysis of young children vaccinated against influenza, birth month was associated with the timing of vaccination through its influence on the timing of preventive care visits. Children born in October were most likely to be vaccinated in October and least likely to have a diagnosis of influenza, consistent with recommendations promoting October vaccination.

Unlocking the Power of Influenza Vaccines for Pediatric Population: A Narrative Review

The flu, often known as influenza, is a dangerous public health hazard for the pediatric population. Immunization is essential for decreasing the burden of the disease and avoiding complications related to influenza. However, the immunogenicity, efficacy, and safety of different influenza vaccines in children warrant careful evaluation. The purpose of this narrative review is to give a summary of the existing literature on the immunogenicity, efficacy, and safety of several vaccinations against influenza viruses in children. The review incorporates evidence from a range of studies focusing on the outcomes of interest. Immunogenicity studies have shown that influenza vaccines induce a robust immune response in children, primarily through neutralizing antibodies' formation. However, variations in vaccine composition influence the duration and magnitude of immune responses. Safety is a crucial consideration in pediatric vaccination. In children, influenza vaccinations have generally shown a high safety profile, with mild and temporary side effects being the most common. Vaccinations against influenza have shown a modest level of efficacy in avoiding hospitalizations linked to influenza, laboratory-confirmed influenza infections, and serious consequences in children. Live attenuated vaccines have shown higher effectiveness against matched strains compared to inactivated vaccines. In conclusion, this narrative review highlights that receiving influenza vaccination in children aged six to 47 months is very important. While different vaccines exhibit varying immunogenicity, safety profiles, and effectiveness, they all contribute to reducing the burden of influenza among children. Future research should focus on optimizing vaccine strategies, improving vaccine coverage, and evaluating long-term protection.

Vaccine Mandates and Influenza Vaccination During the Pandemic

OBJECTIVES

To determine whether a state influenza vaccine mandate and elevated community coronavirus disease 2019 (COVID-19) severity affected a child's probability of receiving an influenza vaccine during the 2020-2021 influenza season, given the child's previous vaccination history.

METHODS

Longitudinal cohort study using enrollment and claims data of 71 333 children aged 6 months to 18 years living in Massachusetts, New Hampshire, and Maine, from a regional insurer. Schoolchildren in Massachusetts were exposed to a new influenza vaccine mandate in the 2020-2021 season. Community COVID-19 severity was measured using county-level total cumulative confirmed case counts between March 2020 and August 2020 and linked by zip codes. The primary outcome of interest was a claim for any influenza vaccine in the 2020-2021 season.

RESULTS

Children living in a state with a vaccine mandate during the 2020-2021 influenza season had a higher predicted probability of receiving an influenza vaccine than those living in states without a mandate (47.7%, confidence interval 46.4%-49.0%, vs 21.2%, confidence interval 18.8%-23.6%, respectively, for previous nonvaccinators, and 78.2%, confidence interval 77.4%-79.0%, vs 58.2%, confidence interval 54.7%-61.7%, for previous vaccinators); the difference was 6.5 percentage points greater among previous nonvaccinators (confidence interval 1.3%-11.7%). Previously vaccinated children had a lower predicted probability of receiving an influenza vaccine if they lived in a county with the highest COVID-19 severity compared with a county with low COVID-19 severity (72.1%, confidence interval 70.5%-73.7%, vs 77.3%, confidence interval 74.7%-79.9%).

CONCLUSIONS

Strategies to improve uptake of influenza vaccination may have differential impact based on previous vaccination status and should account for community factors.

Influenza in Children and Adolescents: Epidemiology, Management, and Prevention

EDUCATION GAP

Influenza is among the most common infectious causes of pediatric emergency department visits and hospitalizations. Clinicians should use evidence-based guidelines to learn how to identify, manage, prevent, and treat influenza cases. Disease caused by influenza virus can be mitigated with appropriate treatment and prevention efforts.

OBJECTIVES After completing this article, readers should be able to:

1. Describe the virology and epidemiology of influenza.

2. List the clinical features and complications of influenza infections.

3. List the benefits and limitations of testing modalities for the diagnosis of influenza.

4. Appropriately apply American Academy of Pediatrics, Infectious Diseases Society of America, and Centers for Disease Control and Prevention (CDC) treatment guidelines for influenza or suspected influenza.

5. Describe the importance of influenza vaccination.

Recommendations for Prevention and Control of Influenza in Children, 2023-2024

This technical report accompanies the recommendations of the American Academy of Pediatrics for the routine use of influenza vaccine and antiviral medications in the prevention and treatment of influenza in children during the 2023-2024 season. The rationale for the American Academy of Pediatrics recommendation for annual influenza vaccination of all children without medical contraindications starting at 6 months of age is provided. Influenza vaccination is an important strategy for protecting children and the broader community against influenza. This technical report summarizes recent influenza seasons, morbidity and mortality in children, vaccine effectiveness, and vaccination coverage, and provides detailed guidance on vaccine storage, administration, and implementation. The report also provides a brief background on inactivated and live-attenuated influenza vaccines, available vaccines this season, vaccination during pregnancy and breastfeeding, diagnostic testing for influenza, and antiviral medications for treatment and chemoprophylaxis. Strategies to promote vaccine uptake are emphasized.

Association of influenza vaccination or influenza virus infection history with subsequent infection risk among children: The Japan Environment and Children's Study (JECS)

We measured the association between history of influenza vaccination by age 2 years and influenza virus (IFV) infection at ages 3 and 4 years by relative risk reduction. We also examined the association between history of IFV infection by age 2 years and recurrent IFV infection at age 3 years. This study included 73,666 children from a large Japanese birth cohort. Among children vaccinated never, once or twice when aged under 2 years, 16.0%, 10.8% and 11.3%, respectively, had been infected with IFV by age 3 years, and 19.2%, 14.5% and 16.0%, respectively, by age 4 years. Compared with no history of influenza vaccination, vaccination at ages 1 and/or 2 years reduced the risk of IFV infection at age 3 by 30%-32% and at age 4 by 17%-24%. The relative risk of recurrent IFV infection at ages 3 and 4 years increased in proportion to the number of prior infections by age 2. One-season-prior influenza vaccination history reduced the IFV infection risk at age 3 years by 25%-42%. Influenza vaccination most effectively protected children at age 3 who lacked older sibling(s) and did not attend nursery school. One-season-prior IFV infection increased the relative risk of recurrent infection at age 3 years (1.72-3.33). In conclusion, influenza vaccination-induced protection may partly extend to the next season. Owing to the relative risk reduction by influenza vaccination and the increased relative risk of IFV infection from prior-season infection, annual influenza vaccination is recommended.

Estimating county-level flu vaccination in the United States

In the United States, influenza vaccines are an important part of public health efforts to blunt the effects of seasonal influenza epidemics. This in turn emphasizes the importance of understanding the spatial distribution of influenza vaccination coverage. Despite this, high quality data at a fine spatial scale and spanning a multitude of recent flu seasons are not readily available. To address this gap, we develop county-level counts of vaccination across five recent, consecutive flu seasons and fit a series of regression models to these data that account for bias. We find that the spatial distribution of our bias-corrected vaccination coverage estimates is generally consistent from season to season, with the highest coverage in the Northeast and Midwest but is spatially heterogeneous within states. We also observe a negative relationship between a county's vaccination coverage and social vulnerability. Our findings stress the importance of quantifying flu vaccination coverage at a fine spatial scale, as relying on state or region-level estimates misses key heterogeneities.

Development of a nomogram for severe influenza in previously healthy children: a retrospective cohort study

OBJECTIVE

We aimed to develop a nomogram to predict the risk of severe influenza in previously healthy children.

METHODS

In this retrospective cohort study, we reviewed the clinical data of 1135 previously healthy children infected with influenza who were hospitalized in the Children's Hospital of Soochow University between 1 January 2017 and 30 June 2021. Children were randomly assigned in a 7:3 ratio to a training or validation cohort. In the training cohort, univariate and multivariate logistic regression analyses were used to identify risk factors, and a nomogram was established. The validation cohort was used to evaluate the predictive ability of the model.

RESULT

Wheezing rales, neutrophils, procalcitonin > 0.25 ng/mL, Mycoplasma pneumoniae infection, fever, and albumin were selected as predictors. The areas under the curve were 0.725 (95% CI: 0.686-0.765) and 0.721 (95% CI: 0.659-0.784) for the training and validation cohorts, respectively. The calibration curve showed that the nomogram was well calibrated.

CONCLUSION

The nomogram may predict the risk of severe influenza in previously healthy children.

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.

Death in children with influenza A (H3N2) virus infection-associated encephalopathy: two case reports

We herein report two cases involving children who died of influenza A (H3N2) virus infection-associated encephalopathy/encephalitis (IAE). Both children developed convulsions and impaired consciousness within a relatively short period and eventually died of brainstem failure. Patient 1 presented with high fever, vomiting, and diarrhea. Laboratory tests indicated persistently high lactate, alanine aminotransferase, and urea nitrogen concentrations in the blood as well as a high protein concentration in the cerebrospinal fluid. Patient 2 presented with persistent hyperthermia and progressive disturbance of consciousness, but the cerebrospinal fluid remained normal during the disease course. Both patients were actively given oseltamivir antiviral treatment after diagnosis of influenza virus infection. However, the disease progressed and invasive mechanical ventilation was performed. Both children's condition quickly progressed to IAE, and they eventually died. IAE is a rare complication of influenza virus infection with high mortality, and its pathogenesis remains unclear. The purpose of this report is to draw attention to the serious central nervous system complications of influenza infection and raise awareness of the fatal consequences of this disease among pediatricians.

Capillary Blood Gas in Children Hospitalized Due to Influenza Predicts the Risk of Lower Respiratory Tract Infection

Background: Influenza may impair respiratory exchange in the case of lower respiratory tract infections (LRTIs). Capillary blood gas (CBG) reflects arterial blood values but is a less invasive method than arterial blood sampling. We aimed to retrospectively verify the usefulness of CBG in pediatric influenza. Material and methods: CBG parameters (pH, pCO2, pO2, SatO2) in laboratory confirmed influenza cases hospitalized in 2013−2020 were verified in terms of LRTI, chest X-ray (CXR) performance, radiologically confirmed pneumonia (CXR + Pneumonia), prolonged hospitalization, and intensive care transfer. A theoretical CBG-based model for CXR performance was created and the odds ratios were compared to the factual CXR performance. Results: Among 409 children (aged 13 days−17 years 3/12, median 31 months), the usefulness of CBG decreased with the age. The SatO2 predicted the LRTI with AUC = 0.74 (95%CI: 0.62−0.86), AUC = 0.71 (0.61−0.82), and AUC = 0.602 (0.502−0.702) in children aged <6 months old (mo), 6−23 mo, 24−59 mo, respectively, while pO2 revealed AUC = 0.73 (0.6−0.85), AUC = 0.67 (0.56−0.78), and AUC = 0.601 (0.501−0.702), respectively. The pCO2 predicted the LRTI most precisely in children <6 months with AUC = 0.75 (0.63−0.87), yet not in older children. A high negative predictive value for CXR + Pneumonia was seen for SatO2 < 6 mo (96.7%), SatO2 6−23 mo (89.6%), pO2 < 6 mo (94.3%), pO2 6−23 mo (88.9%). The use of a CBG-driven CXR protocol (based on SatO2 and pO2) would decrease the odds of an unnecessary CXR in children <2 years old (yo) by 84.15% (74.5−90.14%) and 86.15% (66.46−94.28%), respectively. SatO2 and pO2 also predicted a prolonged hospitalization <6 mo AUC = 0.71 (0.59−0.83) and AUC = 0.73 (0.61−0.84), respectively, and in 6−23 mo AUC = 0.66 (0.54−0.78) and AUC = 0.63 (0.52−0.75), respectively. Conclusions: The CBG is useful mainly in children under two years, predicts the risk of LRTI, and can help exclude the risk of CXR + pneumonia. Children under six months of age represent the group that would benefit the most from CBG. A CBG-based protocol for the performance of CXR could significantly decrease the number of unnecessary CXRs.

Recommendations for Prevention and Control of Influenza in Children, 2022-2023

This technical report accompanies the recommendations of the American Academy of Pediatrics for the routine use of influenza vaccine and antiviral medications in the prevention and treatment of influenza in children during the 2022 to 2023 season. The American Academy of Pediatrics recommends annual influenza vaccination of all children without medical contraindications starting at 6 months of age. Influenza vaccination is an important strategy for protecting children and the broader community as well as reducing the overall burden of respiratory illnesses when other viruses, including severe acute respiratory syndrome-coronavirus 2, are cocirculating. This technical report summarizes recent influenza seasons, morbidity and mortality in children, vaccine effectiveness, and vaccination coverage, and provides detailed guidance on storage, administration, and implementation. The report also provides a brief background on inactivated and live attenuated influenza vaccine recommendations, vaccination during pregnancy and breastfeeding, diagnostic testing, and antiviral medications for treatment and chemoprophylaxis. Updated information is provided about the 2021 to 2022 influenza season, influenza immunization rates, the effectiveness of influenza vaccination on hospitalization and mortality, available vaccines, guidance for patients with history of severe allergic reactions to prior influenza vaccinations, and strategies to promote vaccine uptake.

Influenza vaccines: where we are, where we are going

PURPOSE OF REVIEW

Influenza vaccines are the most useful strategy for preventing influenza illness, especially in the setting of the COVID-19 pandemic. For the coming year (2021/2022) all vaccines will be quadrivalent and contain two influenza A strains [(H1N1)pdm09-like and (H3N2)-like viruses] and two influenza B strains (Victoria lineage-like and Yamagata lineage-like viruses). However, the currently licensed have suboptimal efficacy due to the emergence of new strains and vaccine production limitations. In this review, we summarize the current recommendations as well as new advancements in influenza vaccinations.

RECENT FINDINGS

Recent advances have been aimed at moving away from egg-based vaccines and toward cell culture and recombinant vaccines. This removes egg adaptations that decrease vaccine efficacy, removes the reliance on egg availability and decreases the time necessary to manufacture vaccines. However, even more radical changes are needed if we are to reach the ultimate goal of a universal vaccine capable of providing long-lasting protection against all or at least most influenza strains. We discuss various strategies, including using more stable influenza antigens such as the hemagglutinin stalk and internal proteins as well as new adjuvants, new vaccine formulations, and DNA/RNA-based vaccines that are currently being developed.

SUMMARY

The currently available vaccines have suboptimal efficacy and do not provide adequate protection against drifted and shifted strains. Thus, the development of a universal influenza vaccine that induces long-lasing immunity and protects against a broad range of strains is crucial.

OUP accepted manuscript

Background

Methods

Results

Conclusions