Influenza-like Illness Patients Research Articles

Influenza Vaccine Effectiveness against Influenza A-Associated Outpatient and Emergency-Department-Attended Influenza-like Illness during the Delayed 2022-2023 Season in Beijing, China.

During the 2022-2023 influenza season, the influenza activities in most regions of China were postponed, including Beijing. The unusually delayed influenza epidemic posed a challenge to the effectiveness of the influenza vaccine. Using the test-negative design, we evaluated influenza vaccine effectiveness (VE) during the 2022-2023 influenza season against influenza A-associated outpatient and emergency-department-attended influenza-like illness (ILI) in Beijing, China, from 9 January to 30 April 2023. The analysis included 8301 medically attended ILI patients, of which 1342 (46.2%) had influenza A(H1N1)pdm09, 1554 (53.4%) had influenza A(H3N2), and 11 (0.4%) had co-infection of the two viruses. VE against influenza A-associated ILI patients was 23.2% (95% CI: -6.5% to 44.6%) overall, and 23.1%, 9.9%, and 33.8% among children aged 6 months to 17 years, adults aged 18-59 years, and adults aged ≥60 years, respectively. VE against influenza A(H1N1)pdm09 and against influenza A(H3N2) were 36.2% (95% CI: -1.9% to 60.1%) and 9.5% (95% CI: -34.1% to 39.0%), respectively. VE of the group with vaccination intervals of 14-90 days (70.1%, 95% CI: -145.4 to 96.4) was higher than that of the groups with a vaccination interval of 90-149 days (18.7%, 95% CI: -42.4% to 53.6%) and ≥150 days (21.2%, 95% CI: -18.8% to 47.7%). A moderate VE against influenza A(H1N1)pdm09 and a low VE against influenza A(H3N2) were observed in Beijing during the 2022-2023 influenza season, a season characterized with a delayed and high-intensity influenza epidemic. VE appears to be better within three months after vaccination. Our findings indicate a potential need for the optimization of vaccination policies and underscore the importance of continuous monitoring of influenza to enhance vaccines and optimizing vaccination timing.

Co-detection of respiratory pathogens among ILI patients: characterization of samples collected during the 2018/19 and 2019/20 pre-pandemic seasons

Influenza-like illness (ILI) patients co-detected with respiratory pathogens exhibit poorer health outcomes than those with single infections. To address the paucity of knowledge concerning the incidence of concurrent respiratory pathogens, their relationships, and the clinical differences between patients detected with single and multiple pathogens, we performed an in-depth characterization of the oropharyngeal samples of primary care patients collected in Genoa (Northwest Italy), during winter seasons 2018/19–2019/20.The apriori algorithm was employed to evaluate the incidence of viral, bacterial, and viral-bacterial pairs during the study period. The grade of correlation between pathogens was investigated using the Phi coefficient. Factors associated with viral, bacterial or viral-bacterial co-detection were assessed using logistic regression.The most frequently identified pathogens included influenza A, rhinovirus, Haemophilus influenzae and Streptococcus pneumoniae. The highest correlations were found between bacterial-bacterial and viral-bacterial pairs, such as Haemophilus influenzae-Streptococcus pneumoniae, adenovirus-Haemophilus influenzae, adenovirus-Streptococcus pneumoniae, RSV-A-Bordetella pertussis, and influenza B Victoria-Bordetella parapertussis. Viruses were detected together at significantly lower rates. Notably, rhinovirus, influenza, and RSV exhibited significant negative correlations with each other. Co-detection was more prevalent in children aged < 4, and cough was shown to be a reliable indicator of viral co-detection.Given the evolving epidemiological landscape following the COVID-19 pandemic, future research utilizing the methodology described here, while considering the circulation of SARS-CoV-2, could further enrich the understanding of concurrent respiratory pathogens.

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.

Epidemiology of Human Seasonal Coronaviruses Among People With Mild and Severe Acute Respiratory Illness in Blantyre, Malawi, 2011-2017.

The aim of this study was to characterize the epidemiology of human seasonal coronaviruses (HCoVs) in southern Malawi. We tested for HCoVs 229E, OC43, NL63, and HKU1 using real-time polymerase chain reaction (PCR) on upper respiratory specimens from asymptomatic controls and individuals of all ages recruited through severe acute respiratory illness (SARI) surveillance at Queen Elizabeth Central Hospital, Blantyre, and a prospective influenza-like illness (ILI) observational study between 2011 and 2017. We modeled the probability of having a positive PCR for each HCoV using negative binomial models, and calculated pathogen-attributable fractions (PAFs). Overall, 8.8% (539/6107) of specimens were positive for ≥1 HCoV. OC43 was the most frequently detected HCoV (3.1% [191/6107]). NL63 was more frequently detected in ILI patients (adjusted incidence rate ratio [aIRR], 9.60 [95% confidence interval {CI}, 3.25-28.30]), while 229E (aIRR, 8.99 [95% CI, 1.81-44.70]) was more frequent in SARI patients than asymptomatic controls. In adults, 229E and OC43 were associated with SARI (PAF, 86.5% and 89.4%, respectively), while NL63 was associated with ILI (PAF, 85.1%). The prevalence of HCoVs was similar between children with SARI and controls. All HCoVs had bimodal peaks but distinct seasonality. OC43 was the most prevalent HCoV in acute respiratory illness of all ages. Individual HCoVs had distinct seasonality that differed from temperate settings.

Epidemiology of influenza in Nigeria: A secondary analysis of the sentinel surveillance data in Nigeria from 2010 – 2020

BackgroundInfluenza is a leading cause of morbidity and mortality globally. Little is known of the true burden and epidemiology of influenza in Africa. Nigeria has a sentinel surveillance system for influenza virus (IFV). This study seeks to describe the epidemiological characteristics of influenza cases in Nigeria through secondary data analysis of the sentinel surveillance data from 2010 to 2020. MethodologyA retrospective secondary data analysis of data collected from patients with influenza-like illness (ILI) and severe acute respiratory infection (SARI) in the four Nigeria Influenza Sentinel Surveillance sites from January 2010 to December 2020. Data was cleaned and analyzed using Microsoft Excel and Epi info 7.2 for frequencies and proportions. The results of the analysis were summarized in tables and charts. ResultsA total of 13,828 suspected cases of influenza were recorded at the sentinel sites during the study period. About 10.3% (1421/13,828) of these tested positive for IFV of which 1243 (87.5%) were ILI patients, 175 (12.3%) SARI patients, and 3 (0.2%) novel H1N1 patients. Males accounted for 54.2% (770/1421) of the confirmed cases. The median age of confirmed cases was 3 years (range: <1month–97 years). Children 0–4 years accounted for 69.3% (985/1421) of all cases. The predominant subtypes were B lineage not determined (32.3%), A/H1N1 pdm09 (28.8%) and A/H3 (23.0%). There were periods of sustained transmission in most years with 2011 having the highest number of cases. Overall, there were more cases around January to March and August to November. Heart disease and chronic shortness of breath were the most common co-morbidities identified among confirmed cases. ConclusionInfluenza remains a significant cause of respiratory illness, especially among children aged less than 4 years. Influenza cases occur all year round with irregular seasonality in Nigeria. Children less than 4 years and those with co-morbidities should be prioritized for vaccination. Vaccine composition in the country should take cognizance of the prevailing strains which are type B (lineage not determined), A/H1N1 pdm09 and A/H3.

Genotypes and Phylogenetic Analysis of Human Adenovirus in Hospitalized Pneumonia and Influenza-Like Illness Patients in Jiangsu Province, China (2013-2021).

Human adenovirus (HAdV) is common pathogens that cause various respiratory diseases. The genetic diversity of viruses caused by recombination is considered to be the main source of emerging outbreaks. The aim of this study is to explore the evolutionary relationship and recombination events of HAdV genome in respiratory tract infections in Jiangsu Province. Whole-genome sequencing (WGS) technology was used to sequence 66 patients with HAdV infection (37 patients with influenza-like illness (ILI) and 29 hospitalized patients with pneumonia) from Jiangsu Province. Epidemiological analysis was performed on hospitalized pneumonia and ILI patients infected with HAdV. Subsequently, phylogenetic, recombination, and nucleotide and amino acid identity analyses were performed. Epidemiological analysis of patients undergoing WGS showed that 75.7% of ILI patients were infected with the HAdVB strain and 69.0% of hospitalized pneumonia patients were infected with the HAdVC strain. Moreover, the hospitalized pneumonia and ILI patients infected with HAdV were different in region and time. The strains of HAdVB3 and HAdVB7 genotypes were mainly infected in 2015 and 2017, and the strains of HAdVC1 and HAdVC2 genotypes were mainly infected in 2020. The results of histogram analysis showed that the HAdV strain mainly infected children under 5 years old. In addition, 36 novel recombinant strains were identified. The discovery of these recombinant strains may contribute to understanding the epidemiology of HAdV and research on related vaccines. Furthermore, the percentage of nucleotide and amino acid identities revealed a high level of genetic conservation within isolates from HAdVB3, HAdVB7, HAdVC1, HAdVC2 and HAdVC5 genotypes. The WGS analysis reveals the evolutionary relationships and recombination events of HAdV strains in Jiangsu Province, which is helpful to deepen the understanding of HAdV epidemiology and evolution. In addition, it provides a basis for the formulation of public health strategies in Jiangsu Province.

A combination of annual and nonannual forces drive respiratory disease in the tropics

IntroductionIt is well known that influenza and other respiratory viruses are wintertime-seasonal in temperate regions. However, respiratory disease seasonality in the tropics is less well understood. In this study, we...

Pan-India influenza-like illness (ILI) and Severe acute respiratory infection (SARI) surveillance: epidemiological, clinical and genomic analysis.

Over time, COVID-19 testing has significantly declined across the world. However, it is critical to monitor the virus through surveillance. In late 2020, WHO released interim guidance advising the use of the existing Global Influenza Surveillance and Response System (GISRS) for the integrated surveillance of influenza and SARS-CoV-2. In July 2021, we initiated a pan-India integrated surveillance for influenza and SARS-CoV-2 through the geographically representative network of Virus Research and Diagnostic Laboratories (VRDLs) across 26 hospital and laboratory sites and 70 community sites. A total of 34,260 cases of influenza-like illness (ILI) and Severe acute respiratory infection (SARI) were enrolled from 4 July 2021 to 31 October 2022. Influenza A(H3) and B/Victoria dominated during 2021 monsoon season while A(H1N1)pdm09 dominated during 2022 monsoon season. The SARS-CoV-2 "variants of concern" (VoC) Delta and Omicron predominated in 2021 and 2022, respectively. Increased proportion of SARI was seen in extremes of age: 90% cases in < 1 year; 68% in 1 to 5 years and 61% in ≥ 8 years age group. Approximately 40.7% of enrolled cases only partially fulfilled WHO ILI and SARI case definitions. Influenza- and SARS-CoV-2-infected comorbid patients had higher risks of hospitalization, ICU admission, and oxygen requirement. The results depicted the varying strains and transmission dynamics of influenza and SARS-CoV-2 viruses over time, thus emphasizing the need to continue and expand surveillance across countries for improved decision making. The study also describes important information related to clinical outcomes of ILI and SARI patients and highlights the need to review existing WHO ILI and SARI case definitions.

Diversity of Non-Influenza Respiratory Viruses Associated with Influenza-Like Illness during 2009 pre and pandemic periods in Sao Paulo, Brazil, a Historical Overview

Background and objective: During the 2009 influenza A (H1N1) pandemic, 60% of the respiratory specimens collected from patients under surveillance for influenza-like illness (ILI) in São Paulo, Brazil, tested negative for influenza A and B by Real-Time RT-PCR (RT-qPCR) assays. In this retrospective study, we identified the diversity of other respiratory viruses associated with ILI during the pandemic period and added the benefit of RT-qPCR for their detection. Methods: Five-hundred and forty-two influenza RT-qPCR negative respiratory specimens from ILI patients collected from Jan - Dec 2009, that also tested negative by a commercial Indirect Immuno Fluorescence (IIF) assay for the Respiratory Syncytial Virus (RSV), Parainfluenza (PIV) PIV1, PIV2, PIV 3 and Adenovirus (AdV) were retested by a panel of RT-qPCR assays for the other respiratory viruses, including RSV, Human Metapneumovirus (HMPV), PIV 1-4, AdV, Human Coronaviruses (HCoV) OC43, 229E, NL63 and HKU1, Rhinovirus (RV), Enterovirus (EV) and Human Bocavirus (HBoV). Results: Of the 542 negative specimens, 428 (78%) were positive by RT-qPCR for another respiratory virus: In descending order: RV (149, 27%); RSV (41, 8%); AdV (32, 6%); HMPV (29, 5%); PIV3 (19, 4%); PIV1 (3, 1%); HCoV-OC43 (9, 2%); HBoV (9, 2%); PIV4 (6, 1%); HCoV-HKU1 (6, 1%); EV (5, 1%); HCoV-229E 4 (4, 1%); HCoV-NL63 (3, 1%). Co-detections of two viruses (98, 18%) and three viruses (12, 2%) were common. Conclusion: This retrospective study revealed a high prevalence of respiratory viruses other than influenza associated with ILI during the pandemic period and highlights the superiority of RT-qPCR over IIF for ILI surveillance.

Influenza Vaccine Effectiveness in Preventing Laboratory-Confirmed Influenza Cases and Hospitalizations in Navarre, Spain, 2022-2023.

We estimated influenza vaccine effectiveness (IVE) in preventing outpatient and hospitalized cases in the 2022-2023 season. A test-negative design included a representative sample of outpatients and all hospitalized patients with influenza-like illness (ILI) from October 2022 to May 2023 in Navarre, Spain. ILI patients were tested by PCR for influenza virus. Influenza vaccination status was compared between confirmed influenza cases and test-negative controls. Among 3321 ILI patients tested, IVE to prevent influenza cases was 34% (95% confidence interval (CI): 16 to 48) overall, 85% (95%CI: 63 to 94) against influenza B, and 28% (95%CI: 3 to 46) against A(H3N2). Among 558 outpatients, 222 (40%) were confirmed for influenza: 55% A(H3N2), 11% A(H1N1), and 31% B. Overall, IVE to prevent outpatient cases was 48% (95%CI: 8 to 70), 88% (95%CI: 3 to 98) against influenza B, and 50% (95%CI: -4 to 76) against A(H3N2). Of 2763 hospitalized patients, 349 (13%) were positive for influenza: 64% A(H3N2), 17% A(H1N1), and 8% B. IVE to prevent hospitalization was 24% (95%CI: -1 to 42) overall, 82% (95%CI: 49 to 93) against influenza B, and 16% (95%CI: -17 to 40) against A(H3N2). No IVE was observed in preventing influenza A(H1N1). IVE was high to prevent influenza B, moderate against A(H3N2) and null against A(H1N1). A lower proportion of influenza B cases may explain the smaller IVE in hospitalized patients than in outpatients. The null IVE against A(H1N1) was consistent with the observed antigenic drift and supports the new composition of the 2023-2024 influenza vaccine.

Resurgence of influenza and respiratory syncytial virus in Egypt following two years of decline during the COVID-19 pandemic: outpatient clinic survey of infants and children, October 2022

IntroductionTwo years after unprecedented low rates of circulation of most common respiratory viruses (SARS-CoV-2), the Egyptian ARI surveillance system detected an increase in acute respiratory infections (ARIs) with a reduced circulation of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), especially among school children. A national survey was conducted to estimate the burden and identify the viral causes of ARIs among children < 16 years of age.MethodsA one-day survey was carried out in 98 governmental outpatient clinics distributed all over Egypt 26 governorates. The four largest referral hospitals in each governorate where most influenza-like illness (ILI) patients seek care were selected. Using the WHO case definition, the first five patients < 16 years of age with ILI symptoms visiting the selected outpatient clinics on the survey day were enrolled. Basic demographic and clinical data of patients were collected using a linelist. Patients were swabbed and tested for SARS-CoV-2, influenza, and Respiratory Syncytial virus (RSV) by RT-PCR at the Central Laboratory in Cairo.ResultsOverall, 530 patients enrolled, their mean age was 5.8 ± 4.2, 57.1% were males, and 70.2% reside in rural or semi-rural areas. Of all patients, 134 (25.3%) had influenza, 111 (20.9%) RSV, and 14 (2.8%) coinfections. Influenza-positive children were older compared to RSV, (7.2 ± 4.1, 4.3 ± 4.1, p < 0.001), with more than half of them (53.0%) being school students. Dyspnea was reported in RSV more than in influenza (62.2% vs. 49.3%, p < 0.05). Among RSV patients, children < 2 years had a higher rate of dyspnea than others (86.7% vs. 53.1%, < 0.001).ConclusionsA resurgence of influenza and RSV was detected in Egypt in the 2022–2023 winter season. Influenza caused a higher rate of infection than RSV, while RSV caused more severe symptoms than influenza. Monitoring a broader range of respiratory pathogens is recommended to estimate the ARI burden and risky groups for severe disease in Egypt.

Moderately Low Effectiveness of the Influenza Quadrivalent Vaccine: Potential Mismatch between Circulating Strains and Vaccine Strains.

The annual seasonal influenza vaccination is the most effective way of preventing influenza illness and hospitalization. However, the effectiveness of influenza vaccines has always been controversial. Therefore, we investigated the ability of the quadrivalent influenza vaccine to induce effective protection. Here we report strain-specific influenza vaccine effectiveness (VE) against laboratory-confirmed influenza cases during the 2019/2020 season, characterized by the co-circulation of four different influenza strains. During 2019-2020, 778 influenza-like illness (ILI) samples were collected from 302 (39%) vaccinated ILI patients and 476 (61%) unvaccinated ILI patients in Riyadh, Saudi Arabia. VE was found to be 28% and 22% for influenza A and B, respectively. VE for preventing A(H3N2) and A(H1N1)pdm09 illness was 37.4% (95% CI: 43.7-54.3) and 39.2% (95% CI: 21.1-28.9), respectively. The VE for preventing influenza B Victoria lineage illness was 71.7% (95% CI: -0.9-3), while the VE for the Yamagata lineage could not be estimated due to the limited number of positive cases. The overall vaccine effectiveness was moderately low at 39.7%. Phylogenetic analysis revealed that most of the Flu A genotypes in our dataset clustered together, indicating their close genetic relatedness. In the post-COVID-19 pandemic, flu B-positive cases have reached three-quarters of the total number of influenza-positive cases, indicating a nationwide flu B surge. The reasons for this phenomenon, if related to the quadrivalent flu VE, need to be explored. Annual monitoring and genetic characterization of circulating influenza viruses are important to support Influenza surveillance systems and to improve influenza vaccine effectiveness.

Cost-of-illness comparison between clinical judgment and molecular point-of-care testing for influenza-like illness patients in Germany

A high economic burden stems from seasonal influenza as a well-known but serious public health problem. Rapid diagnostic tests have not yet been integrated into routine use in German primary care, even though they are likely to reduce overall costs in cases of suspected infection. This study aims to demonstrate that the use of point-of-care testing (POCT) produces lower costs of illness compared to the costs incurred by relying on clinical judgment alone. With the help of a decision tree model, two different diagnostic approaches for influenza-like illness (ILI) in primary care were compared: (1) clinical judgment with no technical support and (2) POCT. The costs of illness, as well as their differences, vary widely among the three age groups considered (elderly people, adults, and children). For the pathway of using clinical judgment alone, the costs of illness sum up to 155.99 € for elderly people compared to 76.31 € for adults and 74.15 € for children. With POCT, the costs of illness for the elderly amount to 115,09 €, which is 26% lower than the costs without diagnostic support. The costs for adults and children are 74.42 € and 75.66 €, respectively, which means 2.5% lower costs of illness for adults and 2% higher costs for children. The results demonstrate that the use of POCT to support detecting influenza in ILI patients may reduce the overall cost of illness. The provided data can help governments make informed decisions about potential cost savings by integrating POCT into the reimbursement scheme.

SARS-CoV-2 Surveillance Through China Influenza Surveillance Information System - China, December 1, 2022 to February 12, 2023.

The World Health Organization (WHO) proposed using influenza surveillance systems to carry out coronavirus disease 2019 (COVID-19) surveillance due to the similarity between the two diseases in some respiratory symptoms. To assess the prevalence of COVID-19, we analyzed the influenza-like illness (ILI) and positive rate of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) detections in ILI patients reported to the influenza Surveillance Information System (CNISIS) since late 2022. Data related to ILI were reported by national surveillance sentinel hospitals. Positive testing for SARS-CoV-2 and influenza viruses was conducted using real-time reverse transcription polymerase chain reaction (rRT-PCR) detection by the national influenza surveillance network laboratories. Surveillance data were reported to CNISIS. Beginning on December 12, 2022 (Week 50), the ILI percentage increased dramatically, peaking in Week 51 at 12.1%. Subsequently, the ILI percentage began to decline rapidly from Week 52, 2022, and by Week 6, 2023 (February 6-12), the ILI and ILI percentage had returned to the levels observed at the beginning of December 2022. From December 1, 2022 to February 12, 2023, 115,844 specimens were tested for both SARS-CoV-2 and influenza virus. Of these, 30,381 (26.2%) were positive for SARS-CoV-2 and 1,763 (1.5%) were positive for influenza virus. The positive rate of SARS-CoV-2 tests peaked at 74.1% around December 23 and 25. Sentinel-based surveillance, previously established for influenza, is an effective way to track the circulation trend of SARS-CoV-2 during community-level epidemics. There was no co-prevalence of SARS-CoV-2 and influenza virus during the outbreak of SARS-CoV-2, even during the winter influenza season. However, it is important to remain vigilant for the potential rise of influenza activities following the COVID-19 epidemic.

Breath Biomarkers of Influenza Infection.

Volatile organic compounds (VOCs) are produced systemically due to varied physiological states such as oxidative stress and are excreted through the lungs. Benchtop and preliminary clinical data suggest that breath testing may be a useful diagnostic modality for viral respiratory tract infections. Patients with influenza-like illness (ILI) presenting to a single clinic in San Antonio, Texas, from 3/2017 to 3/2019 submitted a 2-minute breath sample in addition to a nasopharyngeal swab collected for polymerase chain reaction (PCR) assay for respiratory pathogens. VOCs were assayed with gas chromatography-mass spectrometry (GC-MS), and data were analyzed to identify breath VOC biomarkers that discriminated between ILI patients with and without a polymerase chain reaction (PCR) assay that was positive for influenza. Demographic, clinical, PCR, and breath data were available for 237 episodes of ILI, among which 32 episodes (13.5%) were PCR positive for influenza. Twenty candidate VOCs identified patients with influenza with greater than random accuracy. A predictive algorithm using 4 candidate biomarkers identified this group with 78% accuracy (74% sensitivity, 70% specificity). Based on their mass spectra, most of these biomarkers were n-alkane derivatives, consistent with products of oxidative stress. A breath test for VOC biomarkers accurately identified ILI patients with PCR-proven influenza. These findings bolster those of others that a rapid, accurate, universal point-of-care influenza diagnostic test based on assay of exhaled-breath VOCs may be feasible. The next step will be a study of patients with ILI using a simplified method of breath collection that would facilitate translation for use in clinical practice.

Developing and validating clinical features-based machine learning algorithms to predict influenza infection in influenza-like illness patients

BackgroundSeasonal influenza poses a significant risk, and patients can benefit from early diagnosis and treatment. However, underdiagnosis and undertreatment remain widespread. We developed and compared clinical feature-based machine learning (ML) algorithms that can accurately predict influenza infection in emergency departments (EDs) among patients with influenza-like illness (ILI). Material and methodsWe conducted a prospective cohort study in five EDs in the US and Taiwan from 2015 to 2020. Adult patients visiting the EDs with symptoms of ILI were recruited and tested by real-time RT-PCR for influenza. We evaluated seven ML algorithms and compared their results with previously developed clinical prediction models. ResultsOut of the 2189 enrolled patients, 1104 tested positive for influenza. The eXtreme Gradient Boosting achieved superior performance with an area under the receiver operating characteristic curve of 0.82 (95% confidence interval [CI] = 0.79–0.85), with a sensitivity of 0.92 (95% CI = 0.88–0.95), specificity of 0.89 (95% CI = 0.86–0.92), and accuracy of 0.72 (95% CI = 0.69–0.76) in the testing set over cut-offs of 0.4, 0.6 and 0.5, respectively. These results were superior to those of previously proposed clinical prediction models. The model interpretation revealed that body temperature, cough, rhinorrhea, and exposure history were positively associated with and the days of illness and influenza vaccine were negatively associated with influenza infection. We also found the week of the influenza season, pulse rate, and oxygen saturation to be associated with influenza infection. ConclusionsThe clinical feature-based ML model outperformed conventional models for predicting influenza infection.

Oseltamivir Treatment for Influenza During the Flu Season of 2018-2019: A Longitudinal Study.

BackgroundOseltamivir resistance in influenza virus (IFV) has been of widespread concern. An increase in the frequency of viruses with reduced inhibition was observed. Whether oseltamivir is effective is uncertain. We conducted this study to understand the real-world situation in northern China and the clinical efficacy for patients with IFV infection after the use of oseltamivir.MethodsThe longitudinal study was performed on influenza-like illness (ILI) cases in a tertiary general hospital in Beijing, China during the flu season of 2018–2019. All ILI cases (≥18 years) were recruited into the study. We analyzed the effect of the oseltamivir therapy on the number of clinic visits, hospitalization frequency, and the duration of fever and cough.ResultsA total of 689 ILI patients were recruited in this study with 355 in the oseltamivir therapy group and 334 in the supportive therapy group. Among the ILI patients, 388 patients were detected for IFV infection (364 IFV-A and 24 IFV-B) and divided into two groups with or without the oseltamivir therapy (302 vs. 86). There were no significant differences in the basic characteristics between the oseltamivir and supportive therapy groups in the ILI patients or in the IFV positive patients (all p < 0.05). After adjusting for the potential confounders, oseltamivir therapy reduced the times of clinic visits in the ILI and IFV positive patients (p = 0.043 and p = 0.011). No effectiveness with oseltamivir therapy was observed in the outcomes of hospitalization frequency, and the duration of fever and cough.ConclusionOseltamivir use may reduce the times of clinic visits. However, we did not observe the differences in the duration of fever, cough, and the frequency of hospitalization between oseltamivir therapy and supportive therapy.

Influenza circulating viruses, positivity rate and risk factors for influenza associated severe acute respiratory infection during 2018/2019 winter season, Yemen

BackgroundThe burden of seasonal influenza in conflict counties is exacerbated due to limited resource and collapse of health system. During 2018 /2019 season, two-fold increase in the incidence of influenza was reported in Yemen with 22% case fatality of severe acute respiratory infection (SARI). The aims are to analyze the influenza circulating viruses, positivity rate and risk factors for hospitalizing influenza associated-SARI.MethodologyWe used a retrospective analytical study based on surveillance data. All reported patients during 2018/2019 season, fulfilling the WHO cases definition for SARI or influenza like illness (ILI), and had laboratory result from the National Laboratory were included. Influenza positivity rate was calculated, all SARI and ILI patients with positive influenza were included for further analysis by univariate and multivariate binary logistic regression. Crude and adjusted Odds ratio (AOR), 95% confidence interval and P-value < 0.05 were used for statistically significant.ResultsOut of 2186 patients enrolled, 768 patients were tested for influenza viruses,: 19% were children < 15 years, 15% were ≥ 65 years, 69% males and 18% had co-morbidity with chronic diseases. Patients with SARI were 37% and 63% were ILI patients. Influenza viruses were detected in 411 (53.5%), 68% were influenza A subtype (H1N1)pdm09, 27% influenza B and 5% was influenza A not subtyped. The influenza positivity was significantly higher in SARI compared to ILI for patients < 15 years (95% vs, 66%, p < 0.001), and patients ≥ 65 years (83% vs. 56%, p < 0.002), respectively. The highest positivity for influenza type A and B reached 44% and 33% for patients ≥ 65 years and < 15 years, respectively. The risk factors for influenza-associated SARI in multivariate analysis included age < 5 [AOR 2.8] and ≥ 65 years old [AOR 3.1] compared to age 5– < 25 years, diabetes [AOR 4.7], heart diseases [AOR 3.1] and chronic respiratory diseases [AOR 5.0].ConclusionThe influenza positivity during 2018/2019 winter season was high in Yemen and varied by age distribution. Influenza subtype A (H1N1) pdm09 was the predominant and co circulated with influenza B. An influenza vaccination program for the risk group is necessary. Strengthening lab capacity to detect respiratory pathogens and further prospective study for more comprehensive picture are recommended.

Sentinel surveillance for influenza A viruses in Lahore District Pakistan in flu season 2015\u20132016

BackgroundInfluenza A virus (IAV) remains an important global public health threat with limited epidemiological information available from low-and-middle-income countries. The major objective of this study was to describe the proportions, temporal and spatial distribution, and demographic and clinical characteristics of IAV positive patients with influenza like illness (ILI) and severe acute respiratory illness (SARI) in Lahore, Pakistan.MethodsProspective surveillance was established in a sentinel hospital from October 2015 to May 2016. All eligible outpatients and inpatients with ILI or SARI were enrolled in the study. Nasal and/or throat swabs were collected along with clinico-epidemiological data. Samples were tested by real-time RT-PCR (rRT-PCR) to identify IAV and subtype. The descriptive analysis of data was done in R software.ResultsOut of 311 enrolled patients, 284 (91.3%) were ILI and 27 (8.7%) were SARI cases. A distinct peak of ILI and SARI activity was observed in February. Fifty individuals (16%) were positive for IAV with peak positivity observed in December. Of 50 IAV, 15 were seasonal H3N2, 14 were H1N1pdm09 and 21 were unable to be typed. The majority of IAV positive cases (98%) presented with current or history of fever, 88% reported cough and 82% reported sore throat. The most common comorbidities in IAV positive cases were hepatitis C (4%), obesity (4%) and tuberculosis (6%). The highest incidence of patients reporting to the hospital was seen three days post symptoms onset (66/311) with 14 of these (14/66) positive for IAV.ConclusionDistinct trends of ILI, SARI and IAV positive cases were observed which can be used to inform public health interventions (vaccinations, hand and respiratory hygiene) at appropriate times among high-risk groups. We suggest sampling from both ILI and SARI patients in routine surveillance as recommended by WHO.

Epidemiological, Clinical and Virological Profiles of Influenza Infection in the Democratic Republic of the Congo, from 2009 to 2018

Background: To better understand the epidemiological characteristic of influenza infection, the Democratic Republic of Congo set up the sentinel influenza surveillance system in 2007 with eleven health facilities. Oral and nasopharyngeal specimens were sampled from outpatients with influenza-like illness (ILI) and inpatients with severe acute respiratory illness (SARI) using case definitions. Those specimens were shipped to the Influenza National Laboratory for testing with the real-time reverse-transcription polymerase chain reaction. This study aimed to describe ILI and SARI patients’ epidemiological, clinical, and virological profiles. Material and Method: We conducted a cross-sectional study based on a documentary review of suspected notified influenza cases from January 2009 to December 2018. As variables, we exploited sex, age, symptoms, sentinel site of provenance, patient category, viral type and subtype identified, and period of health facility visit. Results: Of 18,461 notified cases, 1795 (9.7%) were positive for the Influenza virus, among them; 53.1% of patients under five years old; 68% of type A virus, 31.5% of type B; 21% of SARI positive vs. 79% for ILI positive cases. The majority of cases occurred during the rainy season. Conclusion: The results of this study contribute to a better understanding of the influenza infection in the Democratic Republic of Congo.