Influenza Antiviral Treatment and Length of Stay

Point of Care Nucleic Acid Testing for Influenza-Like Illness: A Cost-Consequence Analysis for High-Risk Patients in Primary Care in Germany

INTRODUCTION

Influenza A/B virus, severe acute respiratory coronavirus 2 (SARS-CoV-2), and respiratory syncytial virus (RSV) cause similar symptoms, often referred to as influenza-like illness, but require different treatments which must be administered within a short timeframe after symptom onset. This necessitates rapid detection and accurate differentiation by primary care providers, ideally at point of care (POC). POC nucleic acid tests such as the multiplex, real-time polymerase chain reaction (PCR) Xpert® Xpress CoV-2/Flu/RSV plus (Xpert Xpress) offer a faster, more accurate alternative compared to antigen testing, clinical judgement alone, or send-out PCR. This cost-consequence analysis evaluated Xpert Xpress versus conventional testing methods, from a German statutory health insurance (SHI) perspective.

METHODS

A 1-year decision tree was developed to compare Xpert Xpress with antigen testing, send-out PCR, and empiric diagnosis, for influenza A/B virus, SARS-CoV-2, and RSV. The model accounted for diagnostic accuracy and projected the share of patients receiving results within guideline-recommended treatment windows. Data on test accuracy, treatment effects, and costs were sourced from literature and German databases. The main outcome was total cost to the SHI for the 2023/24 respiratory illness season.

RESULTS

Xpert Xpress was associated with the highest number of net correct treatment courses (n = 443,600) versus empiric diagnosis (n = 239,250), antigen testing (n = 347,218), and send-out PCR (n = 280,527). Acquisition costs were highest for Xpert Xpress (EUR 38.4 million versus EUR 27.4 million for antigen testing and EUR 33.5 million for send-out PCR) but were offset by reduced hospitalization and intensive care costs. Overall, Xpert Xpress was associated with cost savings of EUR 1.97 million versus empiric diagnosis, EUR 10.1 million versus antigen testing, and EUR 20.8 million versus send-out PCR.

CONCLUSIONS

Using Xpert Xpress at POC combined fast turnaround with high diagnostic accuracy, thereby increasing correct treatment courses while reducing total costs for influenza, COVID-19, and RSV, offering substantial savings to the German SHI.

Variability of Clinician Recommendations for Oseltamivir in Children Hospitalized With Influenza

BACKGROUND AND OBJECTIVES

Although national recommendations advise antivirals for all hospitalized children with influenza, this recommendation is not supported by high-quality evidence like a randomized clinical trial, and recent data suggest nonadherence to guidelines. Our objective was to describe clinician treatment preferences for oseltamivir in hospitalized children.

METHODS

This cross-sectional survey of pediatricians from 5 specialties was conducted at 7 US children's hospitals from March to June 2024. Four clinical vignettes meeting 2023 American Academy of Pediatrics (AAP) criteria for antiviral treatment were included. Our primary outcome was the average proportion of vignettes for which respondents recommended oseltamivir.

RESULTS

Of 1841 invited participants, 787 (42.7%) completed surveys. Participants were likely to recommend oseltamivir for 49.5% (95% CI, 47.0%-51.9%) of cases; this varied by site from 43.5% to 64.2% and by specialty from 41.6% (hospital medicine) to 70.9% (infectious disease). Longer duration of symptoms and less oxygen support significantly decreased the likelihood of recommending oseltamivir. Awareness of AAP recommendations increased the likelihood of recommending treatment, although aware respondents did not recommend treatment in 38% of cases. Most respondents (87.4%) believed a randomized trial of oseltamivir in hospitalized children was moderately to extremely important.

CONCLUSIONS

Our results demonstrate nonadherence to national recommendations and variability in oseltamivir treatment for children hospitalized with influenza, indicating uncertainty and disagreement regarding which patients benefit from antivirals. A randomized controlled trial of oseltamivir in hospitalized children is needed to help strengthen current influenza treatment recommendations and inform clinicians of treatment benefit in specific pediatric populations.

Influenza and Aging: Clinical Manifestations, Complications, and Treatment Approaches in Older Adults

Influenza, a highly contagious respiratory viral illness, poses significant global health risks, particularly affecting older and those with chronic health conditions. Influenza viruses, primarily types A and B, are responsible for seasonal human infections and exhibit a propensity for antigenic drift and shift, contributing to seasonal epidemics and pandemics. The severity of influenza varies, but severe cases often lead to pneumonia, acute respiratory distress syndrome, and multiorgan failure. Older adults, especially those over 65 years of age, face increased risks of immune senescence, chronic comorbidities, and decreased vaccine efficacy. Globally, influenza affects millions of people annually, with significant morbidity and mortality among older. Epidemiological patterns vary with climate, and risk factors include age, immunocompromised status, and preexisting chronic conditions. In older adults, influenza frequently results in hospitalization and death, which is exacerbated by immunosenescence and biological organ changes associated with aging. Clinical manifestations range from mild symptoms to severe complications such as viral pneumonia and multiorgan failure. Diagnosis often relies on antigen or molecular tests, with radiological examination aiding in severe cases. Treatment primarily involves antiviral agents, such as oseltamivir and peramivir, with the greatest benefit observed when initiated early. Management of severe cases may require hospitalization and supportive care, including addressing complications, such as secondary bacterial infections and cardiovascular events. This article highlights the need for improved vaccination strategies and novel treatments, including monoclonal antibodies and adoptive T cell therapies, to better manage severe influenza infections in vulnerable populations such as older.

Antiviral Use Among Children Hospitalized With Laboratory-Confirmed Influenza Illness: A Prospective, Multicenter Surveillance Study

BACKGROUND

Guidelines state that all hospitalized children with suspected or confirmed influenza receive prompt treatment with influenza-specific antivirals. We sought to determine the frequency of, and factors associated with, antiviral receipt among hospitalized children.

METHODS

We conducted active surveillance of children presenting with fever or respiratory symptoms from 1 December 2016 to 31 March 2020 at 7 pediatric medical centers in the New Vaccine Surveillance Network. The cohort consisted of children hospitalized with influenza A or B confirmed by clinical or research testing. The primary outcome was frequency of antiviral receipt during hospitalization. We used logistic regression to obtain adjusted odds ratios (aORs) and 95% confidence intervals (CIs) for factors associated with antiviral receipt.

RESULTS

A total of 1213 children with laboratory-confirmed influenza were included. Overall, 652 children (53.8%) received an antiviral. Roughly 63.0% of children received clinical influenza testing. Among those with clinical testing, 67.4% received an antiviral. Factors associated with higher odds of antiviral receipt included hematologic (aOR = 1.76; 95% CI = 1.03-3.02) or oncologic/immunocompromising (aOR = 2.41; 95% CI = 1.13-5.11) disorders, prehospitalization antiviral receipt (aOR = 2.34; 95% CI = 1.49-3.67), clinical influenza testing (aOR = 3.07; 95% CI = 2.28-4.14), and intensive care unit admission (aOR = 1.53; 95% CI = 1.02-2.29). Symptom duration >2 days was associated with lower odds of antiviral treatment (aOR = 0.40; 95% CI = .30-.52). Antiviral receipt varied by site with a 5-fold difference across sites.

CONCLUSIONS

Almost half of children hospitalized with influenza did not receive antivirals. Additional efforts to understand barriers to guideline adherence are crucial for optimizing care in children hospitalized with influenza.

Underutilization of Influenza Antiviral Treatment Among Children and Adolescents at Higher Risk for Influenza-Associated Complications - United States, 2023-2024

Annually, tens of thousands of U.S. children and adolescents are hospitalized with seasonal influenza virus infection. Both influenza vaccination and early initiation of antiviral treatment can reduce complications of influenza. Using data from two U.S. influenza surveillance networks for children and adolescents aged <18 years with medically attended, laboratory-confirmed influenza for whom antiviral treatment is recommended, the percentage who received treatment was calculated. Trends in antiviral treatment of children and adolescents hospitalized with influenza from the 2017-18 to the 2023-2024 influenza seasons were also examined. Since 2017-18, when 70%-86% of hospitalized children and adolescents with influenza received antiviral treatment, the proportion receiving treatment notably declined. Among children and adolescents with influenza during the 2023-24 season, 52%-59% of those hospitalized received antiviral treatment. During the 2023-24 season, 31% of those at higher risk for influenza complications seen in the outpatient setting in one network were prescribed antiviral treatment. These findings demonstrate that influenza antiviral treatment is underutilized among children and adolescents who could benefit from treatment. All hospitalized children and adolescents, and those at higher risk for influenza complications in the outpatient setting, should receive antiviral treatment as soon as possible for suspected or confirmed influenza.

Recommendations for Prevention and Control of Influenza in Children, 2024-2025: Technical Report

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 2024 to 2025 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 (nonlive) and live attenuated influenza vaccines, available vaccines for the 2024-2025 influenza season, vaccination during pregnancy and breastfeeding, diagnostic testing for influenza, and antiviral medications for treatment and chemoprophylaxis. Strategies to promote vaccine uptake are emphasized.

Epidemiology of influenza over a ten-year period in Belgium: overview of the historical and current evidence

BACKGROUND

Generally influenza, a contagious respiratory disease, leads to mild illness, but can present as a severe illness with significant complications for some. It entails significant health challenges and an economic burden. Annual vaccination is considered the most effective preventive measure against influenza, especially in high-risk groups.

METHOD

Epidemiological, demographic and vaccination data of influenza from 2009-to-2019 is collected from Sciensano, the Belgian Institute for Health. Sciensano monitors influenza virus through two surveillances: the Influenza-Like Illness (ILI) surveillance in primary care and the Severe Acute Respiratory Infections (SARI) surveillance in hospital settings.

RESULTS

49.6% [± 8.5] of all ILI-samples tested positive in this period. Influenza A was the dominant circulating type, accounting for 73.7% [± 27.5] of positive samples, while influenza B accounted for 24.3% [± 26.7]. For SARI-surveillance, the average rate of samples tested positive was 36.3% [± 9.3]. Influenza A was responsible for respectively 77.7% [± 23.8] of positive samples and influenza B for 22.2% [± 23.7]. Since 2010, epidemics typically lasted about 9.3 weeks [± 2.7]. From 2012 to 2019 the average vaccine effectiveness was 34.9% [± 15.3].

CONCLUSION

Influenza is quickly considered a trivial disease, but can have substantial repercussions. It remains difficult to identify the level of treat of influenza due to antigenic evolution. Measures to prevent, control and treat are needed. Vaccines that provide broader and more durable protection that can be produced more rapidly could be a potential solution.

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.

Management of influenza - updated Swedish guidelines for antiviral treatment

Influenza causes seasonal epidemics of respiratory infection in all parts of the world. Manifestations of influenza range from mild upper to severe lower respiratory tract infection. Medical risk groups are defined by factors predisposing for development of severe disease and are recommended annual vaccination as a protective measure. The previous Swedish treatment guidelines for influenza were issued in 2011, and a review of current evidence was deemed relevant. An important reason to revisit the guidelines is the recent approval of a novel drug for influenza treatment, baloxavir. Updated Swedish evidence-based guidelines created by a group of experts from various research areas, for the management of influenza are presented here. The work has been made in collaboration with the Public Health Agency of Sweden and the Swedish Reference Group for AntiViral therapy (RAV). The updated guidelines include guidelines for diagnostics, treatment and prophylaxis in special groups, including management of pregnant women and children with influenza. A new section about infection control has been added. Pharmacological treatment is covered in detail with regards to indication and dosage. Additionally, drug resistance and environmental aspects are discussed.

Association of Early Oseltamivir With Improved Outcomes in Hospitalized Children With Influenza, 2007-2020

Importance

Oseltamivir is recommended for all children hospitalized with influenza, despite limited evidence supporting its use in the inpatient setting.

Objective

To determine whether early oseltamivir use is associated with improved outcomes in children hospitalized with influenza.

Design, Setting, and Participants

This multicenter retrospective study included 55 799 children younger than 18 years who were hospitalized with influenza from October 1, 2007, to March 31, 2020, in 36 tertiary care pediatric hospitals who participate in the Pediatric Health Information System database. Data were analyzed from January 2021 to March 2022.

Exposures

Early oseltamivir treatment, defined as use of oseltamivir on hospital day 0 or 1.

Main Outcomes and Measures

The primary outcome was hospital length of stay (LOS) in calendar days. Secondary outcomes included 7-day hospital readmission, late (hospital day 2 or later) intensive care unit (ICU) transfer, and a composite outcome of in-hospital death or use of extracorporeal membrane oxygenation (ECMO). Inverse probability treatment weighting (IPTW) based on propensity scoring was used to address confounding by indication. Mixed-effects models were used to compare outcomes between children who did and did not receive early oseltamivir treatment. Outcomes were also compared within high-risk subgroups based on age, presence of a complex chronic condition, early critical illness, and history of asthma.

Results

The analysis included 55 799 encounters from 36 hospitals. The median (IQR) age of the cohort was 3.61 years (1.03-8.27); 56% were male, and 44% were female. A total of 33 207 patients (59.5%) received early oseltamivir. In propensity score-weighted models, we found that children treated with early oseltamivir had shorter LOS (median 3 vs 4 days; IPTW model ratio, 0.52; 95% CI, 0.52-0.53) and lower odds of all-cause 7-day hospital readmission (3.5% vs 4.8%; adjusted odds ratio [aOR], 0.72; 95% CI, 0.66-0.77), late ICU transfer (2.4% vs 5.5%; aOR, 0.41; 95% CI, 0.37-0.46), and the composite outcome of death or ECMO use (0.9% vs 1.4%; aOR, 0.63; 95% CI, 0.54-0.73).

Conclusions and Relevance

Early use of oseltamivir in hospitalized children was associated with shorter hospital stay and lower odds of 7-day readmission, ICU transfer, ECMO use, and death. These findings support the current recommendations for oseltamivir use in children hospitalized with influenza.

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.

Assessment of Temporal Patterns and Patient Factors Associated With Oseltamivir Administration in Children Hospitalized With Influenza, 2007-2020

IMPORTANCE

Oseltamivir therapy is recommended for all pediatric inpatients with influenza, particularly those with high-risk conditions, although data regarding its uptake and benefits are limited.

OBJECTIVE

To describe temporal patterns and independent patient factors associated with the use of oseltamivir and explore patterns in resource use and patient outcomes among children hospitalized with influenza.

DESIGN, SETTING, AND PARTICIPANTS

This multicenter retrospective cross-sectional study was conducted at 36 tertiary pediatric hospitals participating in the Pediatric Health Information System in the US. A total of 70 473 children younger than 18 years who were hospitalized with influenza between October 1, 2007, and March 31, 2020, were included.

EXPOSURES

Hospitalization with a diagnosis of influenza.

MAIN OUTCOMES AND MEASURES

The primary outcome was the use of oseltamivir, which was described by influenza season and by hospital. Patient factors associated with oseltamivir use were assessed using multivariable mixed-effects logistic regression models. Secondary outcomes were resource use (including antibiotic medications, chest radiography, supplemental oxygen, positive pressure ventilation, central venous catheter, and intensive care unit [ICU]) and patient outcomes (length of stay, late ICU transfer, 7-day hospital readmission, use of extracorporeal membrane oxygenation, and in-hospital mortality), which were described as percentages per influenza season.

RESULTS

Among 70 473 children hospitalized with influenza, the median (IQR) age was 3.65 (1.05-8.26) years; 30 750 patients (43.6%) were female, and 39 715 (56.4%) were male. Overall, 16 559 patients (23.5%) were Black, 36 184 (51.3%) were White, 14 133 (20.1%) were of other races (including 694 American Indian or Alaska Native [1.0%], 2216 Asian [3.0%], 372 Native Hawaiian or Pacific Islander [0.5%], and 10 850 other races [15.4%]), and 3597 (5.1%) were of unknown race. A total of 47 071 patients (66.8%) received oseltamivir, increasing from a low of 20.2% in the 2007-2008 influenza season to a high of 77.9% in the 2017-2018 season. Use by hospital ranged from 43.2% to 79.7% over the entire study period and from 56.5% to 90.1% in final influenza season studied (2019-2020). Factors associated with increased oseltamivir use included the presence of a complex chronic condition (odds ratio [OR], 1.42; 95% CI, 1.36-1.47), a history of asthma (OR, 1.31; 95% CI, 1.23-1.38), and early severe illness (OR, 1.19; 95% CI, 1.13-1.25). Children younger than 2 years (OR, 0.81; 95% CI, 0.77-0.85) and children aged 2 to 5 years (OR, 0.83; 95% CI, 0.79-0.88) had lower odds of receiving oseltamivir. From the beginning (2007-2008) to the end (2019-2020) of the study period, the use of antibiotic medications (from 74.4% to 60.1%) and chest radiography (from 59.2% to 51.7%) decreased, whereas the use of oxygen (from 33.6% to 29.3%), positive pressure ventilation (from 10.8% to 7.9%), and central venous catheters (from 2.5% to 1.0%) did not meaningfully change. Patient outcomes, including length of stay (median [IQR], 3 [2-5] days for all seasons), readmissions within 7 days (from 4.0% to 3.4%), use of extracorporeal membrane oxygenation (from 0.5% to 0.5%), and in-hospital mortality (from 1.1% to 0.8%), were stable from the beginning to the end of the study period.

CONCLUSIONS AND RELEVANCE

In this cross-sectional study of children hospitalized with influenza, the use of oseltamivir increased over time, particularly among patients with high-risk conditions, but with wide institutional variation. Patient outcomes remained largely unchanged. Further work is needed to evaluate the impact of oseltamivir therapy in this population.

Influenza

Annual seasonal influenza epidemics of variable severity caused by influenza A and B virus infections result in substantial disease burden worldwide. Seasonal influenza virus circulation declined markedly in 2020-21 after SARS-CoV-2 emerged but increased in 2021-22. Most people with influenza have abrupt onset of respiratory symptoms and myalgia with or without fever and recover within 1 week, but some can experience severe or fatal complications. Prevention is primarily by annual influenza vaccination, with efforts underway to develop new vaccines with improved effectiveness. Sporadic zoonotic infections with novel influenza A viruses of avian or swine origin continue to pose pandemic threats. In this Seminar, we discuss updates of key influenza issues for clinicians, in particular epidemiology, virology, and pathogenesis, diagnostic testing including multiplex assays that detect influenza viruses and SARS-CoV-2, complications, antiviral treatment, influenza vaccines, infection prevention, and non-pharmaceutical interventions, and highlight gaps in clinical management and priorities for clinical research.

Model-based cost-effectiveness analysis of oral antivirals against SARS-CoV-2 in Korea

OBJECTIVES

Many countries have authorized the emergency use of oral antiviral agents for patients with mild-to-moderate cases of coronavirus disease 2019 (COVID-19). We assessed the cost-effectiveness of these agents for reducing the number of severe COVID-19 cases and the burden on Korea’s medical system.

METHODS

Using an existing model, we estimated the number of people who would require hospital/intensive care unit (ICU) admission in Korea in 2022. The treatment scenarios included (1) all adult patients, (2) elderly patients only, and (3) adult patients with underlying diseases only, compared to standard care. Based on the current health system capacity, we calculated the incremental costs per severe case averted and hospital admission for each scenario.

RESULTS

We estimated that 236,510 COVID-19 patients would require hospital/ICU admission in 2022 with standard care only. Nirmatrelvir/ritonavir (87% efficacy) was predicted to reduce this number by 80%, 24%, and 17% when targeting all adults, adults with underlying diseases, and elderly patients (25, 8, and 4%, respectively, for molnupiravir, with 30% efficacy). Nirmatrelvir/ritonavir use is likely to be cost-effective, with predicted costs of US$8,878, US$8,964, and US$1,454, per severe patient averted for the target groups listed above, respectively, while molnupiravir is likely to be less cost-effective, with costs of US$28,492, US$29,575, and US$7,915, respectively.

CONCLUSIONS

In Korea, oral treatment using nirmatrelvir/ritonavir for symptomatic COVID-19 patients targeting elderly patients would be highly cost-effective and would substantially reduce the demand for hospital admission to below the capacity of the health system if targeted to all adult patients instead of standard care.