Influenza in Children

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.

Cell-based influenza vaccines: An effective vaccine option for under 60-year-olds

Aim

Seasonal influenza poses a significant burden of disease, affecting not only older adults but also individuals under the age of 60. It carries a high economic burden, mainly driven by influenza-associated productivity losses in the working population. Conventional egg-based influenza vaccines may have reduced effectiveness due to antigen adaptation in eggs. In contrast, cell-based influenza vaccines are less likely to be affected by such antigen adaptation. This review aims to present real-world data (RWD) comparing the effectiveness of quadrivalent cell-based (QIVc) and egg-based (QIVe) influenza vaccines over three consecutive seasons.

Methods

A comprehensive review was conducted, analyzing RWD from retrospective cohort and case-control studies on the relative vaccine effectiveness (rVE) of QIVc versus QIVe during the 2017/18-2019/20 seasons.

Results

This study included six retrospective cohort studies and one case-control study, with a combined total of approximately 29 million participants. A cohort study involving people aged ≥4 years during the 2017/18 season showed a statistically significant rVE of QIVc compared to QIVe in preventing influenza-like illness, with a value of 36.2%. QIVc demonstrated statistically significant superiority over QIVe in preventing outpatient and inpatient medical encounters as observed in two cohort studies conducted during the 2018/19 and 2019/20 seasons. The rVE of QIVc compared to QIVe was found to be 7.6% in individuals aged ≥4 years and 9.5% in individuals aged ≥18 years. Three additional cohort studies conducted between 2017/18-2019/20 reported a statistically significant improvement in rVE (5.3-14.4%) of QIVc compared to QIVe in preventing influenza-related hospitalizations and emergency department visits due to influenza in individuals aged 4-64 years. In a case-control study across all three seasons, QIVc showed statistically significantly higher effectiveness compared to QIVe in preventing test-confirmed influenza, with rVEs of 10.0-14.8%.

Conclusions

RWD from the 2017/18-2019/20 seasons demonstrated that QIVc is more effective than QIVe in preventing influenza-related outcomes in individuals aged 4-64 years. Preferential use of cell-based influenza vaccines, as opposed to conventional egg-based vaccines, could reduce the burden of influenza-related symptoms on individuals and alleviate the economic impact on the German population under 60 years of age.

[Cell-based influenza vaccines: an effective vaccine option for under 60-year-olds]

The population < 60 years of age is also affected by a significant disease burden from seasonal influenza. It carries a high economic burden, mainly driven by influenza-associated productivity losses in the working population. Conventional egg-based influenza vaccines may experience reduced effectiveness due to antigen adaptation in eggs. In contrast, cell-based influenza vaccines are less likely to be affected by antigenic adaptations to the host system and showed better effectiveness in individuals 4-64 years old over several seasons compared to conventional egg-based influenza vaccines under real-world conditions. Preferential use of cell-based influenza vaccines, as opposed to conventional egg-based vaccines, could reduce the burden of influenza-related symptoms on individuals and alleviate the economic impact on the German population < 60 years of age.

Uncovering the burden of Influenza in children in Portugal, 2008-2018

BACKGROUND

Despite their higher risk of developing severe disease, little is known about the burden of influenza in Portugal in children aged < 5 years old. This study aims to cover this gap by estimating the clinical and economic burden of severe influenza in children, in Portugal, during ten consecutive influenza seasons (2008/09-2017/18).

METHODS

We reviewed hospitalizations in children aged < 5 years old using anonymized administrative data covering all public hospitals discharges in mainland Portugal. The burden of hospitalization and in-hospital mortality directly coded as due to influenza was supplemented by the indirect burden calculated from excess hospitalization and mortality (influenza-associated), estimated for four groups of diagnoses (pneumonia or influenza, respiratory, respiratory or cardiovascular, and all-cause), through cyclic regression models integrating the incidence of influenza. Means were reported excluding the H1N1pdm09 pandemic (2009/10).

RESULTS

The mean annual number of hospitalizations coded as due to influenza was 189 (41.3 cases per 100,000 children aged < 5 years old). Hospitalization rates decreased with increasing age. Nine-in-ten children were previously healthy, but the presence of comorbidities increased with age. Children stayed, on average, 6.1 days at the hospital. Invasive mechanical ventilation was used in 2.4% of hospitalizations and non-invasive in 3.1%. Influenza-associated excess hospitalizations between 2008 and 2018 were estimated at 1,850 in pneumonia or influenza, 1,760 in respiratory, 1,787 in respiratory or cardiovascular, and 1,879 in all-cause models. A total of 95 influenza-associated excess deaths were estimated in all-cause, 14 in respiratory or cardiovascular, and 9 in respiratory models. Over ten years, influenza hospitalizations were estimated to have cost the National Health Service at least €2.9 million, of which 66.5% from healthy children.

CONCLUSIONS

Influenza viruses led to a high number of hospitalizations in children. Most were previously healthy. Results should lead to a reflection on the adequate preventive measures to protect this age group.

The role of meteorological factors on influenza incidence among children in Guangzhou China, 2019-2022

Objective

Analyzing the epidemiological characteristics of influenza cases among children aged 0-17 years in Guangzhou from 2019 to 2022. Assessing the relationships between multiple meteorological factors and influenza, improving the early warning systems for influenza, and providing a scientific basis for influenza prevention and control measures.

Methods

The influenza data were obtained from the Chinese Center for Disease Control and Prevention. Meteorological data were provided by Guangdong Meteorological Service. Spearman correlation analysis was conducted to examine the relevance between meteorological factors and the number of influenza cases. Distributed lag non-linear models (DLNM) were used to explore the effects of meteorological factors on influenza incidence.

Results

The relationship between mean temperature, rainfall, sunshine hours, and influenza cases presented a wavy pattern. The correlation between relative humidity and influenza cases was illustrated by a U-shaped curve. When the temperature dropped below 13°C, Relative risk (RR) increased sharply with decreasing temperature, peaking at 5.7°C with an RR of 83.78 (95% CI: 25.52, 275.09). The RR was increased when the relative humidity was below 66% or above 79%, and the highest RR was 7.50 (95% CI: 22.92, 19.25) at 99%. The RR was increased exponentially when the rainfall exceeded 1,625 mm, reaching a maximum value of 2566.29 (95% CI: 21.85, 3558574.07) at the highest rainfall levels. Both low and high sunshine hours were associated with reduced incidence of influenza, and the lowest RR was 0.20 (95% CI: 20.08, 0.49) at 9.4 h. No significant difference of the meteorological factors on influenza was observed between males and females. The impacts of cumulative extreme low temperature and low relative humidity on influenza among children aged 0-3 presented protective effects and the 0-3 years group had the lowest RRs of cumulative extreme high relative humidity and rainfall. The highest RRs of cumulative extreme effect of all meteorological factors (expect sunshine hours) were observed in the 7-12 years group.

Conclusion

Temperature, relative humidity, rainfall, and sunshine hours can be used as important predictors of influenza in children to improve the early warning system of influenza. Extreme weather reduces the risk of influenza in the age group of 0-3 years, but significantly increases the risk for those aged 7-12 years.

The protective effect of 999 XiaoErGanMao granules on the lungs and intestines of influenza A virus-infected mice

CONTEXT

Gastrointestinal symptoms are a common complication of influenza virus infection in children, which the gut-lung axis become involved in its biological progress. The protective effect of 999 XiaoErGanMao granules (XEGMG) on multi-organ injury in viral pneumonia remains unclear.

OBJECTIVE

To investigate the therapeutic effect of XEGMG on lungs and intestines injury in A/FM/1/47 (H1N1) influenza virus-infected mice.

MATERIALS AND METHODS

Male BALB/c mice were infected with the 2LD₅₀ H1N1 influenza virus and then treated with XEGMG (6 or 12 g/kg) intragastrically once a day for 4 days. The lung and colon samples were then collected for pathological observation, and assays for inflammatory cytokines and intestinal barrier. Mouse feces were collected to evaluate the intestinal microbiota.

RESULTS

Treating with XEGMG (12 g/kg) can mitigate body weight loss caused by 2LD₅₀ H1N1 infection. It can also reduce lung index and pathological damage with the decreased inflammatory cytokines such as IL-6 and IL-1β. Furthermore, XEGMG (12 g/kg) can maintain the goblet cell number in the colons to protect the intestinal barrier and regulate the major flora such as Firmicutes, Bacteroidetes, and Muribaculaceae back to normal. Meanwhile, the expression of IL-17A in the colon tissues was significantly lower in the group of XEGMG (6, 12 g/kg) compared to H1N1 group.

DISCUSSION AND CONCLUSIONS

XEGMG can protect against H1N1 invasion involved in gut-lung axis regulation. The results provide new evidence for the protective effect of XEGMG, which is beneficial to vulnerable children.

Machine-learning-algorithms-based diagnostic model for influenza A in children

BACKGROUND

At present, nucleic acid testing is the gold standard for diagnosing influenza A, however, this method is expensive, time-consuming, and unsuitable for promotion and use in grassroots hospitals. This study aimed to establish a diagnostic model that could accurately, quickly, and simply distinguish between influenza A and influenza like diseases.

METHODS

Patients with influenza-like symptoms were recruited between December 2019 and August 2023 at the Children's Hospital Affiliated to Shandong University and basic information, nasopharyngeal swab and blood routine test data were included. Computer algorithms including random forest, GBDT, XGBoost and logistic regression (LR) were used to create the diagnostic model, and their performance was evaluated using the validation data sets.

RESULTS

A total of 4188 children with influenza-like symptoms were enrolled, of which 1992 were nucleic acid test positive and 2196 were matched negative. The diagnostic models based on the random forest, GBDT, XGBoost and logistic regression algorithms had AUC values of 0.835,0.872,0.867 and 0.784, respectively. The top 5 important features were lymphocyte (LYM) count, age, serum amyloid A (SAA), white blood cells (WBC) count and platelet-to-lymphocyte ratio (PLR). GBDT model had the best performance, the sensitivity and specificity were 77.23% and 80.29%, respectively.

CONCLUSIONS

A computer algorithm diagnosis model of influenza A in children based on blood routine test data was established, which could identify children with influenza A more accurately in the early stage, and was easy to popularize.

Comparative Analysis of Symptomatology in Hospitalized Children with RSV, COVID-19, and Influenza Infections

BACKGROUND The clinical course of respiratory syncytial virus (RSV), SARS-CoV-2, and influenza infections comprises many non-specific symptoms, which makes diagnosis difficult. The aim of this study was to retrospectively analyze the symptomatology of these infections in children and to search for correlations between them. MATERIAL AND METHODS A total of 121 children with a positive RSV (n=61), influenza (n=31), or SARS-CoV-2 (n=29) antigen test were enrolled in this retrospective analysis. Children were aged up to 71 months (median, 8 months). The collected data were collated by performing statistical analysis using the chi-square test and comparing the results using OR (odds ratio) and 95%CI (confidence interval). RESULTS There was a higher risk of fever in children with influenza than in those with RSV. Patients infected with RSV had a higher risk of nasal blockage than those with SARS-CoV-2. Dyspnea was more common in RSV infection than in influenza. Severe, sleep-awakening cough was more frequent in children with RSV than in those with COVID-19. Influenza was more prevalent in children aged >24 months than in those aged 7-24 months. RSV-infected children had a higher risk of numerous auscultatory changes compared to those with SARS-CoV-2. In the case of RSV infection, symptoms requiring hospitalization occurred later than in SARS-CoV-2 infection. CONCLUSIONS Children aged >24 months were at higher risk of contracting influenza. Numerous auscultatory changes, nasal blockage, and dyspnea were more common in children with RSV. There was a higher risk of dyspnea in children with RSV. Fever was more frequent in children with influenza. However, none of the symptoms clearly indicated the etiology of the infection.

Safety and Efficacy of Baloxavir Marboxil in Influenza-infected Children 5-11 Years of Age: A Post Hoc Analysis of a Phase 3 Study

BACKGROUND

miniSTONE-2 (NCT03629184) was a global, phase 3, randomized, controlled study that investigated the safety and efficacy of single-dose baloxavir marboxil in otherwise healthy children 1-<12 years of age and showed a positive risk-benefit profile. This post hoc analysis evaluated the safety and efficacy of baloxavir versus oseltamivir in children 5-11 years old with influenza.

METHODS

Children received single-dose baloxavir or twice-daily oseltamivir for 5 days. Safety was the primary objective. Efficacy and virological outcomes included time to alleviation of symptoms, duration of fever and time to cessation of viral shedding by titer. Data were summarized descriptively.

RESULTS

Ninety-four children 5-11 years old were included (61 baloxavir and 33 oseltamivir). Baseline characteristics were similar between the groups. The incidence of adverse events was balanced and low in both treatment groups, with the most common being vomiting (baloxavir 5% vs. oseltamivir 18%), diarrhea (5% vs. 0%) and otitis media (0% vs. 5%). No serious adverse events or deaths occurred. Median (95% CI) time to alleviation of symptoms with baloxavir was 138.4 hours (116.7-163.4) versus 126.1 hours (95.9-165.7) for oseltamivir; duration of fever was comparable between groups [41.2 hours (23.5-51.4) vs. 51.3 hours (30.7-56.8), respectively]. Median time to cessation of viral shedding was shorter in the baloxavir group versus oseltamivir (1 vs. ≈3 days).

CONCLUSIONS

Safety, efficacy and virological results in children 5-11 years were similar to those from the overall study population 1-<12 years of age. Single-dose baloxavir provides an additional treatment option for pediatric patients 5-11 years old with influenza.

Identifying implementation strategies to address barriers of implementing a school-located influenza vaccination program in Beijing

BACKGROUND

The school-located influenza vaccinations (SLIV) can increase influenza vaccination and reduce influenza infections among school-aged children. However, the vaccination rate has remained low and varied widely among schools in Beijing, China. This study aimed to ascertain barriers and facilitators of implementing SLIV and to identify implementation strategies for SLIV quality improvement programs in this context.

METHODS

Semi-structured interviews were conducted with diverse stakeholders (i.e., representatives of both the Department of Health and the Department of Education, school physicians, class headteachers, and parents) involved in SLIV implementation. Participants were identified by purposive and snowball sampling. The Consolidated Framework for Implementation Research was adopted to facilitate data collection and analysis. Themes and subthemes regarding barriers and facilitators were generated using deductive and inductive approaches. Based on the Consolidated Framework for Implementation Research-Expert Recommendations for Implementing Change (CFIR-ERIC) matching tool, practical implementation strategies were proposed to address the identified barriers of SLIV delivery.

RESULTS

Twenty-four participants were interviewed. Facilitators included easy access to SLIV, clear responsibilities and close collaboration among government sectors, top-down authority, integrating SLIV into the routine of schools, and priority given to SLIV. The main barriers were parents' misconception, inefficient coordination for vaccine supply and vaccination dates, the lack of planning, and inadequate access to knowledge and information about the SLIV. CFIR-ERIC Matching tool suggested implementation strategies at the system (i.e., developing an implementation blueprint, and promoting network weaving), school (i.e., training and educating school implementers), and consumer (i.e., engaging students and parents) levels to improve SLIV implementation.

CONCLUSIONS

There were substantial barriers to the delivery of the SLIV program. Theory-driven implementation strategies developed in this pre-implementation study should be considered to address those identified determinants for successful SLIV implementation.

Risk factors for death associated with severe influenza in children and the impact of the COVID-19 pandemic on clinical characteristics

Background

To summarize the clinical features of severe influenza in children and the high-risk factors for influenza-related deaths and to raise awareness among pediatricians.

Methods

A retrospective study of clinical manifestations, laboratory tests, and diagnosis and treatment of 243 children with severe influenza admitted to Shenzhen Children's Hospital from January 2009 to December 2022 was conducted. Univariate logistic regression analysis and Boruta analysis were also performed to identify potentially critical clinical characteristics associated with death, and clinically significant were used in further multivariate logistic regression analysis. Subject receiver operating characteristic (ROC) curves were applied to assess the efficacy of death-related independent risk factors to predict death from severe influenza.

Results

There were 169 male and 74 female patients with severe influenza, with a median age of 3 years and 2 months and 77.4% of patients under six. There were 46 cases (18.9%) in the death group. The most common pathogen was Influenza A virus (IAV) (81.5%). The most common complication in the death group was influenza-associated acute necrotizing encephalopathy (ANE [52.2%]). Severe influenza in children decreased significantly during the COVID-19 pandemic, with a median age of 5 years, a high predominance of neurological symptoms such as ANE (P = 0.001), and the most common pathogen being H3N2 (P < 0.001). D-dimer, acute respiratory distress syndrome (ARDS), and acute necrotizing encephalopathy (ANE) were significant independent risk factors for severe influenza-associated death. Furthermore, the ROC curves showed that the combined diagnosis of independent risk factors had significant early diagnostic value for severe influenza-related deaths.

Conclusion

Neurological disorders such as ANE are more significant in children with severe influenza after the COVID-19 pandemic. Influenza virus infection can cause serious multisystem complications such as ARDS and ANE, and D-dimer has predictive value for early diagnosis and determination of the prognosis of children with severe influenza.

The Path Towards Effective Respiratory Syncytial Virus Immunization Policies: Recommended Actions

The respiratory syncytial virus (RSV) causes a substantial burden worldwide. After over six decades of research, there is finally a licensed immunization option that can protect the broad infant population, and other will follow soon. RSV immunization should be in place from season 2023/2024 onwards. Doing so requires thoughtful but swift steps. This paper reflects the view of four immunization experts on the efforts being made across the globe to accommodate the new immunization options and provides recommendations organized around five priorities: (I) documenting the burden of RSV in specific populations; (II) expanding RSV diagnostic capacity in clinical practice; (III) strengthening RSV surveillance; (IV) planning for the new preventive options; (V) achieving immunization targets. Overall, Spain has been a notable example of converting RSV prevention into a national desideratum and has pioneered the inclusion of RSV in some of the regional immunization calendars for infants facing their first RSV season.

A colloidal gold test strip based on catalytic hairpin assembly for the clinical detection of influenza a virus nucleic acid

Influenza A epidemics, which occur annually in varying degrees worldwide, is a global challenge to healthcare facilities owing to several limitations of the current detection methods. Therefore, the development of a rapid, convenient, and economical method for the early diagnosis of influenza A will aid clinical treatment and epidemic control. Currently, most of the commonly used clinical rapid tests utilize colloidal gold test strips that detect specific influenza virus antigens but are limited by low sensitivity. Therefore, this study combined catalytic hairpin assembly (CHA) with colloidal gold immunochromatographic assay (GICA) to develop a highly sensitive and visual CHA-GICA test strip. Clinical sample analysis revealed that the sensitivity of the assay was 81.8% and 74% under optimal (35 °C) and room temperature (25 °C) conditions, respectively. In conclusion, this study developed a rapid nucleic acid assay for detecting influenza A virus with high sensitivity and specificity, which can improve the clinical detection of influenza A.

Early peripheral blood lymphocyte subsets and cytokines in predicting the severity of influenza B virus pneumonia in children

Background

Children with influenza B virus infection have a higher susceptibility and higher severity of illness. The activation and disorder of immune function play an important role in the severity of influenza virus infection. This study aims to investigate whether early lymphocyte count and cytokines can provide predictive value for the progression in children with influenza B virus pneumonia.

Methods

A retrospective cohort study was conducted to analyze the clinical data of children with influenza B virus pneumonia from December 1, 2021, to March 31, 2022, in the National Children's Regional Medical Center (Shengjing Hospital of China Medical University). According to the severity of the disease, the children were divided into a mild group and a severe group, and the clinical characteristics, routine laboratory examination, lymphocyte subsets, and cytokines were compared.

Results

A total of 93 children with influenza B virus pneumonia were enrolled, including 70 cases in the mild group and 23 cases in the severe group. Univariate analysis showed that drowsiness, dyspnea, white blood cell (WBC), lymphocytes, monocytes, procalcitonin, alanine aminotransferase (ALT), aspartate aminotransferase (AST), creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), fibrinogen (FIB), Immunoglobulin M (IgM), lung consolidation, total T cell count, CD4⁺ T cell count, CD8⁺ T cell count, NK cell count, NK cell % and B cell % had statistical differences between the mild and severe groups (P<0.05). In multivariate logistic regression analysis, reduced ALT (OR = 1.016), FIB (OR = 0.233), CD8⁺ T cell count (OR = 0.993) and NK cell count (OR = 0.987) were independently associated with the development of severe influenza B virus pneumonia.

Conclusions

The levels of T lymphocytes and NK cells were related to the progression of influenza B virus pneumonia in children, and the reduction of CD8⁺ T cell count and NK cell count can be used as independent risk factors for predicting the severity of influenza B virus pneumonia.

The Spectrum of Influenza in Children

BACKGROUND

Children constitute an important component of the influenza burden and community transmission, but the frequency of asymptomatic infection and post-influenza sequelae at the community level is poorly understood.

METHODS

Two community-based prospective cohort studies (2011-2020, 2017-2020) and 1 case-ascertained study (2012-2017) were conducted in Managua, Nicaragua. Non-immunocompromised children aged 0-14 years with ≥1 influenza infections, determined by polymerase chain reaction and hemagglutination inhibition assay, were included.

RESULTS

A total of 1272 influenza infections occurred in the household-based portion of the study. Influenza infection was asymptomatic in 84 (6.6%) infections, and the asymptomatic fraction increased with age (1.7%, 3.5%, and 9.1% for ages 0-1, 2-4, and 5-14, respectively; P < .001). Of asymptomatic children, 43 (51.2%) shed virus, compared to 1099 (92.5%) symptomatic children (P < .001). Also, 2140 cases of influenza occurred in the primary care portion of the study. Sequelae of influenza were rare, with the most common being pneumonia (52, 2.4%) and acute otitis media (71, 3.3%). A/H1N1 had higher age-adjusted odds of acute otitis media (odds ratio [OR] 1.99, 95% confidence interval [CI]: 1.14-3.48; P = .015) and hospitalization (OR 3.73, 95% CI: 1.68-8.67; P = .002) than A/H3N2. B/Victoria had higher age-adjusted odds of pneumonia (OR 10.99, 95% CI: 1.34-90.28; P = .026) than B/Yamagata.

CONCLUSIONS

Asymptomatic influenza infection is much less common in children than adults, although viral shedding still occurs in asymptomatic children. Post-influenza sequelae are rare in children in the community setting, and virus strain may be important in understanding the risk of sequelae.

The Most Common Location of Schools with Viral Upper Respiratory Tract Infection Clusters in Taiwan, 2011-2019

Clusters of acute upper respiratory tract infections are mainly caused by type A or B influenza virus. Numerous factors modify the risk of upper respiratory tract infection (URTI) cluster transmission. The purpose of this study was to investigate the epidemiological characteristics, differences, and epidemic trends in influenza viruses and in non-influenza respiratory pathogens, and the distribution of the sites of URTI cluster events in Taiwan from 2011 to 2019. We examined the publicly available annual summary data on 1864 confirmed URTI clusters in the Taiwan Centers for Disease Control (Taiwan CDC) from 2011 to 2019. URTI clusters were mainly divided into 1295 clusters of influenza virus infections, 149 clusters of non-influenza respiratory pathogen infections, 341 clusters of pathogens not detected by routine tests, and 79 clusters of unchecked samples. There were statistically significant differences (p < 0.001) in the event numbers of URTI clusters among influenza and non-influenza respiratory pathogens between 2011 and 2019. There were statistically significant differences (p = 0.01) in instances of URTI clusters among non-influenza respiratory pathogens between 2011 and 2019. There were also statistically significant differences (p < 0.001) in instances of URTI clusters in different locations between 2011 and 2019. In all the pathogens of URTI clusters (odds ratio (OR) = 1.89−2.25, p = 0.002−0.004), most single infections were influenza A viruses (64.9%, 937/1444). Respiratory syncytial virus single infections were most numerous (43.0%, 64/149) among the non-influenza respiratory pathogens of URTI clusters. Of the institutions where URTI clusters occurred, schools had the most cases (50.1%, 933/1864) (OR = 1.41−3.02, p < 0.001−0.04). After the categorization of isolated virus strains by gene sequencing, it was found that, of the seasonal influenza A viruses, the H1N1 subtype viruses were predominantly A/California/07/2009, A/Michigan/45/2015, and A/Brisbane/02/2018, and the H3N2 subtype viruses were predominantly A/Hong Kong/4801/2014, A/Singapore/INFIMH-16−0019/2016, and A/Switzerland/8060/2017, during 2017−2019. Of the influenza B viruses, B/Brisbane/60/2008 (B/Vic) was the dominant type, and some were B/Massachusetts/02/2012 (B/Yam) and B/PHUKET/3073/2013 (B/Yam). This study is the first report of confirmed events of URTI clusters from surveillance data provided by the Taiwan CDC (2011−2019). This study highlights the importance of long-term, geographically extended studies, particularly for highly fluctuating pathogens, for understanding the implications of the transmission of URTI clusters in Taiwanese populations. Knowledge gaps and important data have been identified to inform future surveillance and research efforts in Taiwan.

Influenza clinical testing and oseltamivir treatment in hospitalized children with acute respiratory illness, 2015-2016

BACKGROUND

Antiviral treatment is recommended for all hospitalized children with suspected or confirmed influenza, regardless of their risk profile. Few data exist on adherence to these recommendations, so we sought to determine factors associated with influenza testing and antiviral treatment in children.

METHODS

Hospitalized children <18 years of age with acute respiratory illness (ARI) were enrolled through active surveillance at pediatric medical centers in seven cities between 11/1/2015 and 6/30/2016; clinical information was obtained from parent interview and chart review. We used generalized linear mixed-effects models to identify factors associated with influenza testing and antiviral treatment.

RESULTS

Of the 2299 hospitalized children with ARI enrolled during one influenza season, 51% (n = 1183) were tested clinically for influenza. Clinicians provided antiviral treatment for 61 of 117 (52%) patients with a positive influenza test versus 66 of 1066 (6%) with a negative or unknown test result. In multivariable analyses, factors associated with testing included neuromuscular disease (aOR = 5.35, 95% CI [3.58-8.01]), immunocompromised status (aOR = 2.88, 95% CI [1.66-5.01]), age (aOR = 0.93, 95% CI [0.91-0.96]), private only versus public only insurance (aOR = 0.78, 95% CI [0.63-0.98]), and chronic lung disease (aOR = 0.64, 95% CI [0.51-0.81]). Factors associated with antiviral treatment included neuromuscular disease (aOR = 1.86, 95% CI [1.04, 3.31]), immunocompromised state (aOR = 2.63, 95% CI [1.38, 4.99]), duration of illness (aOR = 0.92, 95% CI [0.84, 0.99]), and chronic lung disease (aOR = 0.60, 95% CI [0.38, 0.95]).

CONCLUSION

Approximately half of children hospitalized with influenza during the 2015-2016 influenza season were treated with antivirals. Because antiviral treatment for influenza is associated with better health outcomes, further studies of subsequent seasons would help evaluate current use of antivirals among children and better understand barriers for treatment.

Association between risk perception and influenza vaccine hesitancy for children among reproductive women in China during the COVID-19 pandemic: a national online survey

Background

In China, the national prevalence of parental influenza vaccine hesitancy (IVH) during the pandemic of coronavirus disease 2019 (COVID-19), and the association between risk perception and parental IVH are still unclear. We aimed to explore the association between risk perception and IVH for children among reproductive women in China, a poorly studied area.

Methods

From December 14, 2020, to January 31, 2021, we conducted a national anonymous online survey on IVH for children among reproductive women in China. We assessed risk perception including perceived susceptibility, severity, barriers, and benefits using the Health Belief Model and then classified each variable into three groups based on tertiles. Logistic regression models were used to calculate the adjusted odds ratio (aOR) of risk perception related to vaccine hesitancy after controlling for sociodemographic characteristics, health status, and knowledge of influenza, among other factors. Additionally, subgroup analysis was performed.

Results

Among 3,011 reproductive women, 9.13% reported IVH. In multivariable models, vaccine hesitancy was associated with low perceived susceptibility (aOR = 2.55, 95% CI: 1.79–3.65), higher perceived barriers (moderate: aOR = 1.47, 95% CI: 1.04–2.08; high: aOR = 2.20, 95% CI: 1.47–3.30), and low perceived benefit (moderate: aOR = 1.40, 95% CI: 1.03–1.92; low: aOR = 2.10, 95% CI: 1.43–3.07). Subgroup analysis showed that vaccine hesitancy was more likely to occur among women with high perceived barriers aged < 30 years compared with those older than 30 years (P for difference = 0.041) and among women with moderate perceived benefit who had never conceived compared with those had a history of pregnancy (P for difference = 0.048).

Conclusions

Nearly one in 10 reproductive women was hesitant about influenza vaccination for their children during the COVID-19 pandemic. To mitigate vaccine hesitancy, our findings highlight a need for tailored public health measures to increase perceived disease susceptibility and vaccine benefit and decrease perceived barriers. Furthermore, the effect of high perceived barriers and moderate perceived benefit on vaccine hesitancy was higher among younger women and women who had never conceived.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12889-022-12782-0.

Does Covid-19 in children have a milder course than Influenza?

BACKGROUND

In December 2019, a novel type of coronavirus infection emerged in the Wuhan province of China and began to spread rapidly. In this study, we aimed to determine the differences between COVID-19 disease and Influenza.

METHODS

This retrospective study included 164 children with COVID-19, as well as 46 children with Influenza. The two groups were compared with respect to clinical and laboratory parameters and the rates of intensive care and mechanical ventilation requirement.

RESULTS

In both groups, the most common admission complaints were fever and cough. As compared to the COVID-19 group, the Influenza group had significantly higher rates of cough (37 [80.4%] and 38 [23.2%]), fever (31 [67.4%] and 34 [20.7%]), muscle pain (34 [73.9%] and 31 [18.9%]), vomiting (13 [28.9%] and 8 [4.9%]) and tachypnea (32 [69.6%] and 3 [1.8%]) (P < .01 for all comparisons). The mean WBC count (7.10 ± 1.08 vs. 10.90 ± 1.82), mean neutrophil count (3.19 ± 0.58 vs. 6.04 ± 0.97), APTT, CRP, procalcitonin, ALT, and LDH levels were significantly lower in the COVID-19 group compared to the Influenza group (P < .05 for all comparisons). There was, however, no significant difference between the mean lymphocyte counts of both groups. The Influenza group had significantly higher rates of intensive care requirement (19 [41.3%] vs. 3 [1.8%]) and mechanical ventilation requirement (16 [34.8%] vs. 2 [1.2%]) as well as a significantly higher mortality rate (7 [15.2%] vs. 2 [1.2%]) than the COVID-19 group (P < .01).

CONCLUSION

COVID-19 and Influenza may share similar clinical features. According to our findings, however, we believe that COVID-19 disease has a milder clinical and laboratory course than Influenza in children.

Influenza Anti-Stalk Antibodies: Development of a New Method for the Evaluation of the Immune Responses to Universal Vaccine

Growing interest in universal influenza vaccines and novel administration routes has led to the development of alternative serological assays that are able to detect antibodies against conserved epitopes. We present a competitive ELISA method that is able to accurately determine the ratio of serum immunoglobulin G directed against the different domains of the hemagglutinin, the head and the stalk. Human serum samples were treated with two variants of the hemagglutinin protein from the A/California/7/2009 influenza virus. The signals detected were assigned to different groups of antibodies and presented as a ratio between head and stalk domains. A subset of selected sera was also tested by hemagglutination inhibition, single radial hemolysis, microneutralization, and enzyme-linked lectin assays. Pre-vaccination samples from adults showed a quite high presence of anti-stalk antibodies, and the results were substantially in line with those of the classical serological assays. By contrast, pre-vaccination samples from children did not present anti-stalk antibodies, and the majority of the anti-hemagglutinin antibodies that were detected after vaccination were directed against the head domain. The presented approach, when supported by further assays, can be used to assess the presence of specific anti-stalk antibodies and the potential boost of broadly protective antibodies, especially in the case of novel universal influenza vaccine approaches.