Economic burden of influenza illness among children under 5 years in Suzhou, China: Report from the cost surveys during 2011/12 to 2016/17 influenza seasons

Caregiver Burden among Patients with Influenza or Influenza-like Illness (ILI): A Systematic Literature Review

Influenza and influenza-like illness (ILI) pose significant clinical and economic burdens globally each year. This systematic literature review examined quantitative studies evaluating the impact of patients' influenza/ILI on their caregivers' well-being, focusing on health-related quality of life (HRQoL), work productivity, and activity impairment. A comprehensive search across six databases, including the Cochrane Database of Systematic Reviews, Embase, MEDLINE via PubMed, Ovid, PsycNet, and Web of Science, yielded 18,689 records, of which 13,156 abstracts were screened, and 662 full-text articles were reviewed from January 2007 to April 2024. Thirty-six studies [HRQoL: 2; productivity: 33; both: 1] covering 22 countries were included. Caregivers of 47,758 influenza or ILI patients across 123 study cohorts were assessed in the review. The mean workday loss among caregivers ranged from 0.5 to 10.7 days per episode, influenced by patients' influenza status (positive or negative), disease severity (mild or moderate-to-severe), age, viral type (influenza A or B), and vaccination/treatment usage. The HRQoL of caregivers, including their physical and emotional well-being, was affected by a patient's influenza or ILI, where the severity and duration of a patient's illness were associated with worse HRQoL. This review shows that the consequences of influenza or ILI significantly affect not only patients but also their caregivers.

Costs and cost-effectiveness of influenza illness and vaccination in low- and middle-income countries: A systematic review from 2012 to 2022

BACKGROUND

Historically, lack of data on cost-effectiveness of influenza vaccination has been identified as a barrier to vaccine use in low- and middle-income countries. We conducted a systematic review of economic evaluations describing (1) costs of influenza illness; (2) costs of influenza vaccination programs; and (3) vaccination cost-effectiveness from low- and middle-income countries to assess if gaps persist that could hinder global implementation of influenza vaccination programs.

METHODS AND FINDINGS

We performed a systematic search in Medline, Embase, Cochrane Library, CINAHL, and Scopus in January 2022 and October 2023 using a combination of the following key words: "influenza" AND "cost" OR "economic." The search included studies with publication years 2012 through 2022. Studies were eligible if they (1) presented original, peer-reviewed findings on cost of illness, cost of vaccination program, or cost-effectiveness of vaccination for seasonal influenza; and (2) included data for at least 1 low- or middle-income country. We abstracted general study characteristics and data specific to each of the 3 study types. Of 54 included studies, 26 presented data on cost-effectiveness, 24 on cost-of-illness, and 5 on program costs. Represented countries were classified as upper-middle income (UMIC; n = 12), lower-middle income (LMIC; n = 7), and low-income (LIC; n = 3). The most evaluated target groups were children (n = 26 studies), older adults (n = 17), and persons with chronic medical conditions (n = 12); fewer studies evaluated pregnant persons (n = 9), healthcare workers (n = 5), and persons in congregate living settings (n = 1). Costs-of-illness were generally higher in UMICs than in LMICs/LICs; however, the highest national economic burden, as a percent of gross domestic product and national health expenditure, was reported from an LIC. Among studies that evaluated the cost-effectiveness of influenza vaccine introduction, most (88%) interpreted at least 1 scenario per target group as either cost-effective or cost-saving, based on thresholds designated in the study. Key limitations of this work included (1) heterogeneity across included studies; (2) restrictiveness of the inclusion criteria used; and (3) potential for missed influenza burden from use of sentinel surveillance systems.

CONCLUSIONS

The 54 studies identified in this review suggest an increased momentum to generate economic evidence about influenza illness and vaccination from low- and middle-income countries during 2012 to 2022. However, given that we observed substantial heterogeneity, continued evaluation of the economic burden of influenza illness and costs/cost-effectiveness of influenza vaccination, particularly in LICs and among underrepresented target groups (e.g., healthcare workers and pregnant persons), is needed. Use of standardized methodology could facilitate pooling across settings and knowledge sharing to strengthen global influenza vaccination programs.

Cost-effectiveness of seasonal influenza vaccination of children in China: a modeling analysis

BACKGROUND

China has a high burden of influenza-associated illness among children. We aimed to evaluate the cost-effectiveness of introducing government-funded influenza vaccination to children in China (fully-funded policy) compared with the status quo (self-paid policy).

METHODS

A decision tree model was developed to calculate the economic and health outcomes, from a societal perspective, using national- and provincial-level data. The incremental cost-effectiveness ratio (ICER) [incremental costs per quality-adjusted life year (QALY) gained] was used to compare the fully-funded policy with the self-paid policy under the willingness-to-pay threshold equivalent to national and provincial GDP per capita. Sensitivity analyses were performed and various scenarios were explored based on real-world conditions, including incorporating indirect effect into the analysis.

RESULTS

Compared to the self-paid policy, implementation of a fully-funded policy could prevent 1,444,768 [95% uncertainty range (UR): 1,203,446-1,719,761] symptomatic cases, 92,110 (95% UR: 66,953-122,226) influenza-related hospitalizations, and 6494 (95% UR: 4590-8962) influenza-related death per season. The fully-funded policy was cost-effective nationally (7964 USD per QALY gained) and provincially for 13 of 31 provincial-level administrative divisions (PLADs). The probability of a funded vaccination policy being cost-effective was 56.5% nationally, and the probability in 9 of 31 PLADs was above 75%. The result was most sensitive to the symptomatic influenza rate among children under 5 years [ICER ranging from - 25,612 (cost-saving) to 14,532 USD per QALY gained]. The ICER of the fully-funded policy was substantially lower (becoming cost-saving) if the indirect effects of vaccination were considered.

CONCLUSIONS

Introducing a government-funded influenza policy for children is cost-effective in China nationally and in many PLADs. PLADs with high symptomatic influenza rate and influenza-associated mortality would benefit the most from a government-funded influenza vaccination program.

Platelet count and risk of severe illness in hospitalised children with Influenza-Like illness

AIM

To examine the clinical significance of thrombocytosis (platelets > 500 × 109 /L) in admitted children with an influenza-like illness.

METHODS

We performed a database analysis consisting of patients evaluated at our medical centers with an influenza-like illness between 2009 and 2013. We included paediatric patients and examined the association between platelet count, respiratory viral infections, and admission outcomes (hospital length of stay and admission to the paediatric intensive care unit) using regression models adjusting for multiple variables.

RESULTS

A total of 5171 children were included in the study cohort (median age 0.8 years; interquartile range, 0.2-1.8; 58% male). Younger age, and not the type of viral infection, was associated with a high platelet count (p < 0.001). Elevated platelet count independently predicted admission outcomes (p ≤ 0.05). The presence of thrombocytosis was associated with an increased risk for a prolonged length of stay (odds ratio = 1.2; 95% Confidence interval = 1.1 to 1.4; p = 0.003) and admission to the paediatric intensive care unit (odds ratio = 1.5; 95% Confidence interval = 1.1 to 2.0; p = 0.002).

CONCLUSION

In children admitted with an influenza-like illness, a high platelet count is an independent predictor of admission outcomes. Platelet count may be used to improve risk assessment and management decisions in these paediatric patients.

The CD19+ B cell as a marker for the febrile children infected with influenza A and Omicron variant

H3N2 and Omicron are common pathogens of respiratory infections in children. This study aimed to explore dynamic changes of lymphocyte subsets and the diagnostic value of CD19+ B cell in children infected with influenza A and Omicron. One hundred and sixty-five in-patients with H3N2, 175 in-patients with Omicron variant, and 50 age-matched healthy children from Children's Hospital of Soochow University were included in this study. The participants underwent 13 respiratory pathogens by DNA polymerase chain reaction (PCR), sputum culture, severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) DNA PCR, routine blood, and lymphocyte subset assays within 24 h of admission. The neutrophils, neutrophil-to-lymphocyte ratio, and monocyte-to-lymphocyte ratio in the H3N2 and Omicron groups were significantly higher than in the control groups (p < 0.05). However, the lymphocytes and eosinophils in the H3N2 and Omicron groups were lower than the control groups (p < 0.05). The CD3+ T cell, CD3+ CD4+ T cell, CD3+ CD8+ T cell, CD3- CD19+ B cell, and natural killer cell were lower in the H3N2 and Omicron groups than in the control group (p < 0.05). The CD3- CD19+ cell in the Omicron group was higher than that in the H3N2 group but lower than that in the control group (p < 0.05). In addition, CD3- CD19+ cell had good diagnostic value for H3N2 (area under the receiver operating characteristic curve = 0.902, p < 0.05). The children with H3N2 were more likely to have lower lymphocytes than children with Omicron. Additionally, B-cell count had good diagnostic value for H3N2.

Fu-Zheng-Xuan-Fei formula promotes macrophage polarization and Th17/Treg cell homeostasis against the influenza B virus (Victoria strain) infection

ETHNOPHARMACOLOGICAL RELEVANCE

Fu-Zheng-Xuan-Fei formula (FF) is a prescription that has been clinically used through the basic theory of traditional Chinese medicine (TCM) for treating viral pneumonia. Although FF possesses a prominent clinical therapeutic effect, seldom pharmacological studies have been reported on its anti-influenza B virus (IBV) activity.

AIM OF THE STUDY

Influenza is an acute infectious respiratory disease caused by the influenza virus, which has high annual morbidity and mortality worldwide. With a global decline in the COVID-19 control, the infection rate of influenza virus is gradually increasing. Therefore, it is of great importance to develop novel drugs for the effective treatment of influenza virus. Apart from conventional antiviral drugs, TCM has been widely used in the clinical treatment of influenza in China. Therefore, studying the antiviral mechanism of TCM can facilitate the scientific development of TCM.

MATERIALS AND METHODS

Madin-Darby canine kidney cells (MDCK) and BALB/c mice were infected with IBV, and FF was added to evaluate the anti-IBV effects of FF both in vitro and in vivo by Western blotting, immunofluorescence, flow cytometry, and pathological assessment.

RESULTS

It was found that FF exhibited anti-viral activity against IBV infection both in vivo and in vitro, while inducing macrophage activation and promoting M1 macrophage polarization. In addition, FF effectively regulated the signal transducer and activator of transcription (STAT) signaling pathway-mediated Th17/Treg balance to improve the lung tissue damage caused by IBV infection-induced inflammation. The findings provided the scientific basis for the antiviral mechanism of FF against IBV infection.

CONCLUSIONS

This study shows that FF is a potentially effective antiviral drug against IBV infection.

Impact of Influenza and Influenza-Like Illness on Work Productivity Outcomes: A Systematic Literature Review

BACKGROUND

Influenza is a persistent public health problem with a significant burden on patients, employers, and society. A systematic review by Keech and Beardsworth (2008) characterized the burden of influenza/influenza-like illness (ILI) on absenteeism. We conducted a systematic literature review evaluating the impact of influenza/ILI on work productivity among adults as an update to the work of Keech and Beardsworth.

METHODS

This systematic review identified studies evaluating the impact of influenza/ILI on absenteeism, presenteeism, or related work productivity measures for employees and employed caregivers based on laboratory confirmation, physician diagnosis, and/or self-reported illness. Eligible studies were in English, French, or German published from 7 March 2007 through 15 February 2022, in PubMed, Embase, or BIOSIS. Two reviewers completed screening and full-text review, with conflicts resolved by a third advisor. Summary data were extracted by two analysts; all records were quality checked by one analyst. Work productivity outcomes were summarized qualitatively, and risk of bias was not evaluated.

RESULTS

A total of 14,387 records were retrieved; 12,245 titles/abstracts were screened and 145 full-text publications were reviewed, of which 63 were included in the qualitative assessment. Studies of self-reported ILI were most frequent (49%), followed by laboratory-confirmed cases (37%) and physician diagnoses (11%). Overall, approximately 20-75% of employees missed work due to illness across study settings and populations. Mean time out of work among ill employees varied widely across study designs and populations, ranging from < 1 to > 10 days, and was often reported to be approximately 2-3 days. Considerable heterogeneity was observed across study designs, populations, and outcomes. Most employees (≈ 60-80%) reported working while experiencing influenza/ILI symptoms. Reporting of costs was sparse and heterogeneous; one study reported annual costs of influenza-related absences equating to $42,851 per 100,000 employee health plan members. Results were partitioned based on the following categories. Among otherwise healthy adults, 1-74% of workers missed ≥1 workday due to influenza/ILI, for a mean [standard deviation (SD)] of 0.5 (1.44) to 5.3 (4.50) days, and 42-89% reported working while ill, for a mean (SD) of 0.3 (0.63) to 4.4 (3.73) days. Among working caregivers, 50-75% missed work to care for children/household members with influenza/ILI, for 1-2 days on average. Similarly, the mean absenteeism among healthcare workers ranged from 0.5 to 3.2 days. Across studies evaluating vaccination status, generally smaller proportions of vaccinated employees missed time from work due to influenza/ILI.

CONCLUSIONS

This systematic review summarized the productivity burden of influenza/ILI on the worldwide working-age population. Despite notable heterogeneity in study designs, influenza/ILI case definitions, and productivity outcome measures, this review highlighted the substantial productivity burden that influenza/ILI may have on employees, employers, and society, consistent with the findings of Keech and Beardsworth (2008).

Impact of COVID-19 pandemic on influenza virus prevalence in children in Sichuan, China

We performed a retrospective analysis of influenza A and B virus antigen detection data in children in Sichuan Province from January 2019 to December 2021, with the goal of studying the impact of the COVID-19 pandemic on influenza circulation in children in Sichuan, China. During the pandemic, both the number of specimens and the positive rates of the influenza virus fell dramatically. The positivity for influenza A virus decreased from 22.5% in 2019 to 9.9% in 2020 to 0.2% in 2021 (p < 0.001). The lowest and highest positive rates for the influenza B virus occurred in 2020 and 2021, respectively, with a statistically significant 3-year comparison (p < 0.001). During the pandemic, the annual positivity remained higher in school-age than in preschoolers, while there was no difference in the annual positivity between the two gender groups, both consistent with the prepandemic results. During the pandemic, the seasonality of influenza A and B was different from that before the pandemic. In 2019, the epidemic season for influenza A was autumn and winter, while the epidemic season for influenza B was winter and spring. Seasonal changes in influenza A were insignificant after the pandemic, and influenza B became predominant in 2021, with a high prevalence in the autumn. Although influenza activity decreased during the COVID-19 pandemic, one should be on the lookout for a possible rebound in influenza circulation in the future.

Clinical efficacy and safety of baloxavir marboxil in the treatment of influenza: A systematic review and meta-analysis of randomized controlled trials

PURPOSE

The aim of this meta-analysis is to compare the clinical efficacy and safety of baloxavir with other anti-influenza agents or placebo in the treatment of influenza.

METHODS

PubMed, Embase, Web of Science, Google Scholar, Scopus, CINAHL, Cochrane databases and clinical registration were searched from inception until February 15 2021 for relevant randomized controlled trials (RCTs). Only phase 3 RCTs evaluating the usefulness of baloxavir in the treatment of influenza were included.

RESULTS

Three RCTs enrolling 3771 patients (baloxavir group, n = 1451; oseltamivir group, n = 1288; placebo group, n = 1032) were included. Compared with oseltamivir, baloxavir had an insignificantly shorter time to the alleviation of symptoms (mean difference [MD], -1.29 h; 95% CI, -6.80 to 4.21; I² = 0%). In contrast, baloxavir had a significantly shorter time to the alleviation of symptoms than placebo (MD, -26.32 h; 95% CI, -33.78 to -18.86; I² = 0%). Baloxavir was associated with a significant decline in influenza virus titers and viral RNA load compared to oseltamivir and placebo. Baloxavir was associated with a lower risk of any adverse events than oseltamivir (OR, 0.82; 95% CI, 0.69-0.98; I² = 0%) and placebo (OR, 0.79; 95% CI, 0.66-0.96; I² = 0%).

CONCLUSIONS

The findings of this meta-analysis suggested that baloxavir is superior to placebo in the treatment of influenza in both clinical outcome and virological response. Moreover, baloxavir was found to have a better virological response than oseltamivir and to be as effective as oseltamivir clinically. Compared with oseltamivir and placebo, baloxavir appears to be a relatively safe anti-influenza agent.