Hospital-acquired Influenza Research Articles

Prediction of hospital-acquired influenza using machine learning algorithms: a comparative study

BackgroundHospital-acquired influenza (HAI) is under-recognized despite its high morbidity and poor health outcomes. The early detection of HAI is crucial for curbing its transmission in hospital settings.AimThis study aimed to investigate factors related to HAI, develop predictive models, and subsequently compare them to identify the best performing machine learning algorithm for predicting the occurrence of HAI.MethodsThis retrospective observational study was conducted in 2022 and included 111 HAI and 73,748 non-HAI patients from the 2011–2012 and 2019–2020 influenza seasons. General characteristics, comorbidities, vital signs, laboratory and chest X-ray results, and room information within the electronic medical record were analysed. Logistic Regression (LR), Random Forest (RF), Extreme Gradient Boosting (XGB), and Artificial Neural Network (ANN) techniques were used to construct the predictive models. Employing randomized allocation, 80% of the dataset constituted the training set, and the remaining 20% comprised the test set. The performance of the developed models was assessed using metrics such as the area under the receiver operating characteristic curve (AUC), the count of false negatives (FN), and the determination of feature importance.ResultsPatients with HAI demonstrated notable differences in general characteristics, comorbidities, vital signs, laboratory findings, chest X-ray result, and room status compared to non-HAI patients. Among the developed models, the RF model demonstrated the best performance taking into account both the AUC (83.3%) and the occurrence of FN (four). The most influential factors for prediction were staying in double rooms, followed by vital signs and laboratory results.ConclusionThis study revealed the characteristics of patients with HAI and emphasized the role of ventilation in reducing influenza incidence. These findings can aid hospitals in devising infection prevention strategies, and the application of machine learning-based predictive models especially RF can enable early intervention to mitigate the spread of influenza in healthcare settings.

Proposed new definition for hospital-acquired SARS-CoV-2 infections: results of a confirmatory factor analysis.

The present study aims to develop and discuss an extension of hospital-acquired severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections (HA-SIs) definition which goes beyond the use of time parameters alone. A confirmatory factor analysis was carried out to test a suitable definition for HA-SI. A two-center cohort study was carried out at two tertiary public hospitals in the German state of lower Saxony. The study involved a population of 366 laboratory-confirmed SARS-CoV-2-infected inpatients enrolled between March 2020 and August 2023. The proposed model shows adequate fit indices (CFI.scaled = 0.959, RMSEA = 0.049). A descriptive comparison with existing classifications revealed strong features of our model, particularly its adaptability to specific regional outbreaks. The use of the regional incidence as a proxy variable to better define HA-SI cases represents a pragmatic and novel approach. The model aligns well with the latest scientific results in the literature. This work successfully unifies, within a single model, variables which the recent literature described as significant for the onset of HA-SI. Further potential improvements and adaptations of the model and its applications, such as automating the categorization process (in terms of hospital acquisition) or employing a comparable model for hospital-acquired influenza classification, are subjects open for discussion.

Influenza A subtype H3N2 is associated with an increased risk of hospital dissemination – an observational study over six influenza seasons

Previous studies on hospital-acquired influenza (HAI) have not systematically evaluated the possible impact of different influenza subtypes. HAI has historically been associated with high mortality, but clinical consequences may be less severe in a modern hospital setting. To identify and quantify HAI for each season, investigate possible associations with varying influenza subtypes, and to determine HAI-associated mortality. All influenza-PCR-positive adult patients (>18 years old) hospitalized in Skåne County during 2013-2019, were prospectively included in the study. Positive influenza samples were subtyped. Medical records of patients with suspected HAI were examined to confirm a nosocomial origin and to determine 30-day mortality. Of 4110 hospitalized patients with a positive influenza PCR, 430 (10.5%) were HAI. Influenza A(H3N2) infections were more often HAI (15.1%) than influenza A(H1N1)pdm09, and influenza B (6.3% and 6.8% respectively, P<0.001). The majority of HAI caused by H3N2 were clustered (73.3 %) and were the cause of all 20 hospital outbreaks consisting of ≥4 affected patients. In contrast, the majority of HAI caused by influenza A(H1N1)pdm09 and influenza B were solitary cases (60% and 63.2%, respectively, P<0.001). Mortality associated with HAI was 9.3% and similar between subtypes. HAI caused by influenza A(H3N2) was associated with an increased risk of hospital dissemination. Our study is relevant for future seasonal influenza infection control preparedness and shows that subtyping of influenza may help to define relevant infection control measures. Mortality in HAI remains substantial in a modern hospital setting.

Patient influenza vaccination reduces the risk of hospital-acquired influenza: An incident test negative-case control study in Lyon university hospital, France (2004–2020)

BackgroundLiterature is limited on the impact of patient vaccination on the risk of hospital-acquired influenza (HAI). This test negative case-control study nested in a surveillance program aimed at evaluating the effectiveness of influenza vaccination in reducing the risk of HAI in hospitalized patients during 15 influenza seasons (2004–05 to 2019–20). MethodsHAI cases were those who developed influenza like illness (ILI) symptoms at least 72 h after hospitalization and had a positive reverse transcriptase-polymerase chain reaction (RT-PCR). Controls were those with ILI symptoms and a negative RT-PCR test. A nasal swab as well as socio-demographic, clinical data and information on influenza vaccination were collected. ResultsOf the 296 patients included, 67 were confirmed HAI cases. Influenza vaccine coverage was significantly higher among controls compared to HAI cases (p = 0.002). The risk of HAI was reduced by almost 60 % in vaccinated patients. ConclusionsA better control of HAI can be achieved by vaccinating hospitalized patients.

Poor hospitalization outcomes in patients undergoing allogeneic hematopoietic stem cell transplant with hospital acquired influenza infection.

Although hospital-acquired influenza infection (HAII) is a known complication among immunocompromised patients, the data in the setting of hospitalization for allogeneic hematopoietic stem cell transplant (allo-HSCT) are scarce. A retrospective study using the National Inpatient sample database was done to determine the impact of HAII on hospitalization outcomes among patients admitted for allo-HSCT. The data for 77103 allo-HSCT weighted hospitalizations were collected between 2002 and 2019. Among these, only 314 (0.4%) allo-HSCT cases were billed for HAII. Patients with influenza were more likely to have comorbid conditions like chronic obstructive lung disease, diabetes mellitus, hypertension, and myocardial infarction. Multivariate logistic regression revealed that patients with influenza had a higher risk of all-cause mortality: (odds ratio = 4.87, 95% confidence interval: 3.63-6.54; p < .01). Patients with influenza also had statistically higher odds of developing acute kidney injury, septic shock, and respiratory failure requiring mechanical ventilation. They also had a significantly longer length of stay (34 days versus 26 days) and adjusted cost for hospitalization ($195345 versus $121967). Our large analysis of real-world data reveals that patients undergoing allo-HSCT that develop HAII are at substantially higher risk of inpatient complications and death.

Nosocomial influenza in a pediatric general ward: Effects of isolation and cohort placement of children with influenza.

Many studies have described nosocomial outbreaks of influenza in specialized wards. We evaluated nosocomial transmission of influenza in a pediatric general ward. Retrospective observational study. Single secondary hospital. The study included 814 hospitalized children with influenza between September 2015 and August 2020. The medical records of the included children were retrospectively reviewed, and clinical characteristics of children with community-acquired (CA) influenza and hospital-acquired (HA) influenza were determined. The room of each included child during hospitalization was traced to identify the children exposed to them. CA influenza and HA influenza were diagnosed in 789 (96.9%) and 25 (3.1%) children, respectively. Among children with CA influenza, 691 (87.6%) were isolated or place in a cohort on admission. In total, 98 children (12.4%) admitted to multibed rooms exposed 307 children with noninfluenza diseases to influenza during 772 patient days; 3 exposed children (1.0%) were diagnosed with HA influenza. Including these 3 children, 25 children (19 without definite in-hospital exposure to influenza and 3 exposed to other children with HA influenza) were diagnosed with HA influenza, and 11 (44.0%) exposed 31 children with noninfluenza diseases to influenza for 85 patient days. Also, 3 exposed children (9.7%) were diagnosed with HA influenza, a significantly higher rate than that for CA influenza (P = .005). The clinical characteristics were comparable between children with HA influenza and those with CA influenza. Cohort placement of children with influenza in a pediatric general ward can be effective in controlling nosocomial transmission of influenza. However, control measures for children with HA influenza should be emphasized.

Investigating Epidemiologic and Molecular Links Between Patients With Community- and Hospital-Acquired Influenza A: 2017-2018 and 2019-2020, Michigan.

Hospital-acquired influenza virus infection (HAII) can cause severe morbidity and mortality. Identifying potential transmission routes can inform prevention strategies. We identified all hospitalized patients testing positive for influenza A virus at a large, tertiary care hospital during the 2017-2018 and 2019-2020 influenza seasons. Hospital admission dates, locations of inpatient service, and clinical influenza testing information were retrieved from the electronic medical record. Time-location groups of epidemiologically linked influenza patients were defined and contained ≥1 presumed HAII case (first positive ≥48 hours after admission). Genetic relatedness within time-location groups was assessed by whole genome sequencing. During the 2017-2018 season, 230 patients tested positive for influenza A(H3N2) or unsubtyped influenza A including 26 HAIIs. There were 159 influenza A(H1N1)pdm09 or unsubtyped influenza A-positive patients identified during the 2019-2020 season including 33 HAIIs. Consensus sequences were obtained for 177 (77%) and 57 (36%) of influenza A cases in 2017-2018 and 2019-2020, respectively. Among all influenza A cases, there were 10 time-location groups identified in 2017-2018 and 13 in 2019-2020; 19 of 23 groups included ≤4 patients. In 2017-2018, 6 of 10 groups had ≥2 patients with sequence data, including ≥1 HAII case. Two of 13 groups met this criteria in 2019-2020. Two time-location groups from 2017-2018 each contained 3 genetically linked cases. Our results suggest that HAIIs arise from outbreak transmission from nosocomial sources as well as single infections from unique community introductions.

Impact and characteristics of hospital-acquired influenza over 10 seasons in a third-level university hospital

ObjectivesTo analyze the characteristics of patients with nosocomial flu, to compare them with patients with community-acquired influenza to study possible differences and to identify possible risk factors associated with this type of flu. Patients and methodsObservational, cross-sectional and retrospective study of hospitalized patients with a microbiological confirmation of influenza in a third-level university hospital over 10 seasons, from 2009 to 2019. Nosocomial influenza was defined as that infection whose symptoms began 72h after hospital admission, and its incidence, characteristics and consequences were further analyzed. ResultsA total of 1260 hospitalized patients with a microbiological diagnosis of influenza were included, which 110 (8.7%) were nosocomial. Patients with hospital-acquired influenza were younger (71.74±16.03 years, P=0.044), had a longer hospital stay (24.25±20.25 days, P<0.001), had more frequently a history of chronic pulmonary pathologies (P=0.010), immunodeficiency (P<0.001), and were associated with greater development of bacterial superinfection (P<0.001), respiratory distress (P=0.003), and admission to the intensive care unit (ICU) (P<0.001). In the multivariate logistic regression analysis, the following characteristics were identified as independent risk factors: immunodeficiency (ORa=2.33; 95% CI: 1.47–3.60); ICU admission (ORa=4.29; 95% CI: 2.23–10.91); bacterial superinfection (ORa=1.64; 95% CI: 1.06–2.53) and respiratory distress (ORa=3.88; 95% CI: 1.23–12.23). ConclusionsNosocomial influenza is more common in patients with a history of immunodeficiency. In addition, patients with hospital-acquired influenza had an increased risk of bacterial superinfection, admission to the ICU, and development of respiratory distress.

Rural hospital bed management practices during influenza season.

Rural health services face greater challenges in managing infectious patients due to lack of specialty beds and longer lengths of stay. The pressures of seasonal influxes of influenza patients with a heavy burden of chronic disease and an ageing population result in an increased demand for hospital beds. During these peak periods it is common for rural hospitals to experience bed block. The result is that patients may be placed into any available bed or ward at the time, increasing the need for transfer and the risk of spreading hospital-acquired respiratory illnesses to other patients and staff across the hospital. This further exacerbates bed block, with patients then requiring more specialised treatment and longer lengths of stay. This places additional strain on already existing workforce shortages and limited resources that must accommodate higher-than-normal patient loads. The objective of this study was to examine rural hospital bed management practices with a focus on the transfer of patients who are actively diagnosed with influenza (either on admission or during their stay in hospital) and to investigate the association of increased bed movement with the rate of nosocomial transmission and staff workload. The rates of patients admitted to a rural hospital in New South Wales, Australia, during the yearly peak influenza season (July to September) during 2016-2019 with either community-acquired or hospital-acquired influenza were examined using an infection control surveillance program. Bed management practices related to these inpatients were audited to examine their contribution towards nosocomial transmissions and staff workload during these periods. A total of 229 patients presented to this hospital with an influenza diagnosis over the study period and generated 175 bed transfers. Forty percent of community-acquired and 70% of hospital-acquired influenza inpatients experienced one or more intrahospital bed transfers during their active infection period. Half of all bed transfers involved patients being transferred to another ward (interward) and the other half consisted of those transferred within the same ward (intraward). These transfers impacted staff workload, requiring a total of 245 extra hours from nursing and cleaning staff to facilitate - time not included when allocating staff at the start of each shift. Findings from this study indicate that there is no active strategy for influenza containment during high-occupancy periods for this rural facility. This resulted in multiple bed transfers occurring during the active phase of influenza infection. This then led to an exacerbation of bed block and thus further inappropriate placement of newly admitted patients. The development of an optimal bed management plan for future surges of influenza and other highly infectious respiratory illnesses is essential to reduce nosocomial infection and staff workload, especially given the limited resources available in rural areas compared to metropolitan centres.

Impacto y características de la gripe nosocomial a lo largo de 10 temporadas en un hospital universitario de tercer nivel

ObjectivesTo analyze the characteristics of patients with nosocomial flu, to compare them with patients with community-acquired influenza to study possible differences and to identify possible risk factors associated with this type of flu. Patients and methodsObservational, cross-sectional and retrospective study of hospitalized patients with a microbiological confirmation of influenza in a third-level university hospital over 10seasons, from 2009 to 2019. Nosocomial influenza was defined as that infection whose symptoms began 72h after hospital admission, and its incidence, characteristics and consequences were further analyzed. ResultsA total of 1260 hospitalized patients with a microbiological diagnosis of influenza were included, which 110 (8.7%) were nosocomial. Patients with hospital-acquired influenza were younger (71.74±16.03 years, P=0.044), had a longer hospital stay (24.25±20.25 days, P<0.001), had more frequently a history of chronic pulmonary pathologies (P=0.010), immunodeficiency (P<0.001), and were associated with greater development of bacterial superinfection (P<0.001), respiratory distress (P=0.003), and admission to the intensive care unit (ICU) (P<0.001). In the multivariate logistic regression analysis, the following characteristics were identified as independent risk factors: immunodeficiency (ORa=2.33; 95% CI: 1.47-3.60); ICU admission (ORa=4.29; 95% CI: 2.23-10.91); bacterial superinfection (ORa=1.64; 95% CI: 1.06-2.53) and respiratory distress (ORa=3.88; 95% CI: 1.23-12.23). ConclusionsNosocomial influenza is more common in patients with a history of immunodeficiency. In addition, patients with hospital-acquired influenza had an increased risk of bacterial superinfection, admission to the ICU, and development of respiratory distress.

17. A Retrospective Cohort Study of Influenza Infected Multiple Myeloma Patients Comparing Clinical Outcomes Between Vaccinated and Unvaccinated

BackgroundThe current standard of care for multiple myeloma (MM) patients is to administer the influenza vaccine (InfV) annually. While in immunocompetent patients, the influenza vaccine is associated with significant benefit in morbidity and mortality, the inherent immunodeficiency from MM and its treatments reduce the InfV efficacy but it is thought to have some benefit. The effect on morbidity and mortality in MM patients has not been evaluated. Our study aims to investigate whether InfV vaccination status affects outcomes of MM patients diagnosed with Influenza A or B (FluA, FluB). MethodsThis was a retrospective study, using Arkansas Clinical Data Repository, which identified all MM patients diagnosed with FluA or FluB during five consecutive flu seasons from September 1st to April 30th, 2015-2020. Those with hospital-acquired influenza were excluded. The outcome data were collected for 30 days following the initial diagnosis. Fisher Exact test was used to compare categorical variables, and Mann Whitney U test to compare continuous variables. ResultsWe identified 194 MM patients diagnosed with FluA or FluB. Sixty-five (34%) were vaccinated and 129 (66%) were not vaccinated. A total of 87 (45%) were admitted to the hospital. Twenty-five (38%) of the vaccinated vs. 62 (48%) of the unvaccinated group were hospitalized (p=0.22), and 4/65 vaccinated vs. 12/129 unvaccinated required ICU treatment (p=0.59). Two patients in the vaccinated and 3 in the non-vaccinated group were intubated (p=1). The mean length of stay (LOS) for the vaccinated and unvaccinated was 10 days and 14 days, respectively, which was not significantly different (p=0.197). Two (3%) patients died within 30 days of diagnosis in the vaccinated group while four (3%) died in the unvaccinated group (p=1).ConclusionThe InfV status of MM patients had no effect on outcomes including the need for hospital admission, ICU stay, mechanical ventilation, LOS, and death. Hospitalization was common, but severe illness requiring ICU care and intubation were less common. Six patients died within 30 days of influenza diagnosis. Vaccination strategy, including high-dose and repeat doses, should be examined in MM patients. Disclosures All Authors: No reported disclosures

Hospital-acquired influenza in the United States, FluSurv-NET, 2011-2012 through 2018-2019.

To estimate population-based rates and to describe clinical characteristics of hospital-acquired (HA) influenza. Cross-sectional study. US Influenza Hospitalization Surveillance Network (FluSurv-NET) during 2011-2012 through 2018-2019 seasons. Patients were identified through provider-initiated or facility-based testing. HA influenza was defined as a positive influenza test date and respiratory symptom onset >3 days after admission. Patients with positive test date >3 days after admission but missing respiratory symptom onset date were classified as possible HA influenza. Among 94,158 influenza-associated hospitalizations, 353 (0.4%) had HA influenza. The overall adjusted rate of HA influenza was 0.4 per 100,000 persons. Among HA influenza cases, 50.7% were 65 years of age or older, and 52.0% of children and 95.7% of adults had underlying conditions; 44.9% overall had received influenza vaccine prior to hospitalization. Overall, 34.5% of HA cases received ICU care during hospitalization, 19.8% required mechanical ventilation, and 6.7% died. After including possible HA cases, prevalence among all influenza-associated hospitalizations increased to 1.3% and the adjusted rate increased to 1.5 per 100,000 persons. Over 8 seasons, rates of HA influenza were low but were likely underestimated because testing was not systematic. A high proportion of patients with HA influenza were unvaccinated and had severe outcomes. Annual influenza vaccination and implementation of robust hospital infection control measures may help to prevent HA influenza and its impacts on patient outcomes and the healthcare system.

A Meta-Analysis on Evaluation of Nosocomial Infections Amongst Patients in a Tertiary Care Hospital.

Background Hospital-acquired infections, also known as nosocomial infections, are one of the many severe outcomes amongst patients in tertiary care hospitals. Hospital-acquired influenza is amongst the most common infection which has affected huge population. Objective We have performed a meta-analysis in order to summarize the effects of epidemiology and clinical characteristics in HAI. Methods We performed literature review with help of PubMed, Cochrane Library, Embase, Scopus, Web of Science, China National Knowledge Infrastructure (CNKI), The Global Index Medicus (GIM), and other clinical databases till 2021. Many random models were used in order to obtain pooled proportions, mean difference, odds ratio, and CI. Results A total of six studies were analyzed, where a total of 491 nosocomial and 4030 nonnosocomial infection cases were reported. The odds ratio of mortality was 0.02 with 95% CI and the risk ration for males was 1.08 with 95% CI. Conclusion The proportion of nosocomial infections in cases of influenza was higher in patients admitted in tertiary care hospitals. Thus, a surveillance system for vaccination for all the high-risk patients must be made mandatory.

Is it possible to hospitalize patients in multiple-bed room without increasing the risk of hospital-acquired influenza? Description of a pragmatic preventive strategy in a French university hospital

Large inrush of patients through Emergency Department during influenza season can be dramatic. The purpose of this study was to evaluate the impact of an emergency preventive strategy, namely admission of patients with influenza in multiple-bed room with patients free from influenza, on the occurrence of hospital-acquired influenza (HAI). When a patient with an influenza RT-PCR diagnosis was hospitalized in a multiple-bed room, the emergency preventive strategy was applied: selection of non-immunocompromised neighbor, implementation of physical barriers (rigid screen pulled between beds, surgical mask for healthcare workers and visitors), preemptive Oseltamivir therapy for the neighbor. From 29/11/2017 to 10/05/2018 a total of 464 hospitalized influenza patients were included; 318 were placed in multiple-bed room and 141 in single room. Emergency preventive strategy was correctly applied for 75.1% of patients in multiple-bed room. A total of 8 exposed neighbors matched HAI definition despite strategy. 7 were already exposed to the case before the set-up of the strategy. Only one case of documented transmission of influenza occurred after application of an incorrect emergency preventive strategy: preventive posology of Oseltamivir was not correct. These preliminary results suggest that the occurrence of HAI in multiple-bed rooms can be limited by the implementation of maximum precautions and urge us to promote further evaluation of the strategy. A detection bias should be considered without a systematic neighbors monitoring.

The epidemiological and clinical characteristics of the hospital-acquired influenza infections: A systematic review and meta-analysis.

Background:The hospital-acquired influenza (HAI) were usually contributed to severe outcomes among the inpatients. Here, we performed a meta-analysis to summarize and quantify the epidemiological and clinical characteristics of HAI.Methods:We performed a literature search thorough PubMed, Web of Science, Cochrane Library, Embase, Scopus and China National Knowledge Infrastructure (CNKI), and Wanfang databases for observational studies. Random/fix-effects models were used to obtain pooled proportion, odds ratio (OR), and weighted mean difference (WMD).Results:A total of 14 studies involving 1483 HAI and 71849 non-hospital-acquired influenza infections (NHAI) cases were included.The proportion of the HAI among the influenza cases was 11.38% (95% confidence interval [CI]: 5.19%–19.55%) and it was increased after 2012 (6.15% vs 12.72%). The HAI cases were significantly older (WMD = 9.51, 95% CI: 0.04–18.98) and the patients with chronic medical diseases were at increased risk of HAI (OR = 1.85, 95% CI: 1.57–2.19). Among them, metabolic disorders (OR = 8.10, 95% CI: 2.46–26.64) ranked the highest danger, followed by malignancy (OR = 3.18, 95% CI: 2.12–4.76), any chronic diseases (OR = 2.81, 95% CI: 1.08–9.31), immunosuppression (OR = 2.13, 95% CI: 1.25–3.64), renal diseases (OR = 1.72, 95% CI:1.40–2.10), heart diseases (OR = 1.52, 95% CI: 1.03–1.44), and diabetes (OR = 1.22, 95% CI: 1.03–1.44). The HAI cases were more likely to experience longer hospital stay (WMD = 10.23, 95% CI: 4.60–15.85) and longer intensive care unit (ICU) stay (WMD = 2.99, 95% CI: 1.50–4.48). In the outcomes within 30 days, those population was still more likely to receive hospitalization (OR = 6.55, 95% CI: 5.19–8.27), death in hospital (OR = 1.99, 95% CI: 1.65–2.40) but less likely to discharged (OR = 0.20, 95% CI: 0.16–0.24).Conclusion:The proportion of the HAI among the influenza cases was relatively high. Reinforcement of the surveillance systems and vaccination of the high-risk patients and their contacts are necessary for the HAI control.

Outcomes of point-of-care testing for influenza in the emergency department of a tertiary referral hospital in Ireland

Seasonal influenza causes significant morbidity and mortality, and represents a recurring financial burden for community- and hospital-based treatment. Nosocomial outbreaks exacerbate the impact of influenza. Rapid diagnosis of influenza has been shown to reduce transmission. However, point-of-care testing (POCT) in emergency departments and prudent direction of patients with the virus to reduce hospital-acquired infection (HAI) have not been evaluated widely. To assess performance characteristics of the Abbott ID NOW™ Influenza A & B 2 system, impact on incidence of hospital-acquired influenza, and admission rate ratio for patients who have POCT compared with laboratory testing. POCT was introduced in the 2018-2019 influenza season. Data from then were compared with preceding and subsequent seasons. Records of POCT and laboratory testing for the 2017-2018, 2018-2019, and 2019-2020 influenza seasons were analysed. Sensitivity and specificity of POCT were compared pairwise with Xpert Flu A/B/RSV. Patient admission rates and time of waiting for admission were compared. Compared to laboratory assay, POCT demonstrated sensitivity of 90.6% (95% confidence interval (CI): 78.6-96.5) and specificity of 99.2% (95.2-100) for influenza A, with 51.4% and 41.9% reductions in numbers of HAIs observed in the two seasons when POCT was available, respectively. The admission rate ratio for influenza cases diagnosed by POCT compared with laboratory diagnosis was 0.72 (95% CI: 0.53-0.97; P= 0.031). POCT for influenza appears a feasible strategy for testing of patients during peak influenza virus season, with potential to reduce HAI. The relatively rapid turnaround time may also benefit clinical management of patients presenting at emergency departments with suspected influenza.

Population Mortality and Laws Encouraging Influenza Vaccination for Hospital Workers.

Since 1995, 14 states have passed laws encouraging or mandating influenza vaccination for hospital workers. Although the Centers for Disease Control and Prevention recommends vaccinating health care workers to reduce disease transmission and patient risk, the effect of these laws on pneumonia and influenza mortality is unknown. To measure the effect of state-level hospital worker influenza vaccination laws on pneumonia and influenza mortality. Quasi-experimental observational study. United States. Population of all states from 1995 to 2017. State adoption of a law promoting influenza vaccination for hospital workers. Pneumonia and influenza mortality per 100 000 persons by state and by month, both population-wide and separately by age group, obtained from restricted-access National Vital Statistics System files. Linear and log-linear models were used to compare changes in mortality rates for adopting versus nonadopting states. Implementation of state laws requiring hospitals to offer influenza vaccination to their employees was associated with a 2.5% reduction in the monthly pneumonia and influenza mortality rate (-0.16 deaths per 100 000 persons [95% CI, -0.29 to -0.02]; P = 0.022) during the years when the vaccine was well matched to the circulating strains. The largest effects occurred among elderly persons and during peak influenza months. Utilization of large-scale national data precluded analysis of more specific outcomes, such as laboratory-confirmed or hospital-acquired influenza. State laws promoting hospital worker vaccination against influenza may be effective in preventing pneumonia- and influenza-related deaths, particularly among elderly persons. Vaccinating hospital workers may substantially reduce the spread of influenza and protect the most vulnerable populations. None.

Incidence of hospital-acquired influenza in adults: A prospective surveillance study from 2004 to 2017 in a French tertiary care hospital

Hospital-acquired influenza potentially leads to significant morbidity and mortality in already vulnerable patients, but its overall burden is not fully understood. We undertook this study to estimate the incidence and trends of hospital-acquired laboratory-confirmed influenza among adults, and to compare clinical characteristics between hospital-acquired and community-acquired influenza cases. This was a prospective surveillance study over 11 years of adults with influenza-like-illness (ILI) hospitalized in surgery, medicine and geriatric wards in a tertiary acute-care hospital in Lyon, France. Nasal swabs were systematically collected from those with ILI and tested for influenza by reverse transcriptase-polymerase chain reaction at the national influenza reference laboratory (Lyon, France). Influenza was laboratory confirmed at a rate of 1 in 13 patients who developed ILI during their hospitalization. Having an underlying disease was an important characteristic of hospital-acquired ILI cases. Cardiovascular disease was the most frequent underlying condition in both influenza-positive and influenza-negative patients. Complications were more frequent for influenza-positive than influenza-negative patients. The influenza incidence rate was highest in the geriatric ward and increased over the study period. Hospital-acquired influenza poses a significant risk to already vulnerable patients. Longitudinal surveillance data are essential to support better recognition and monitoring of viral infections in hospitals.

Influenza surveillance: Findings from a tertiary care adult hospital in Singapore, Jan 2010–Sept 2019

Background: Influenza virus infection is known to cause excessive hospitalisations and deaths in the elderly during seasonal peaks and pandemics. Methods and materials: We conducted a retrospective, observational cohort study on patients admitted to Tan Tock Seng Hospital from 1 Jan 2010 to 30 Sept 2019. Results: During the study period, 11,728 patients were identified with laboratory-confirmed influenza, influenza A 8,783 (75%) and influenza B 2,945 (25%) respectively. Majority of influenza cases were elderly (68% aged >65 y) with 51% of female, and 8,872 (76%) patients had Charlson co-morbidity score <3. 483 (4%) nosocomial influenza cases (patients had laboratory confirmation >3 d after admission) were identified. Influenza A/B ratio was significantly different between nosocomial and non-nosocomial cases (p = 0.002). Individuals with nosocomial influenza (median 74; range 21–102 y) were older than non-nosocomial cases (median 72; range 13–110 y) (p < 0.001). 49 deaths (10%) occurred among patients with nosocomial influenza infections. During the study period, 754 severely ill patients (who required intensive care and/or died) were identified with overall 6.4% (p = 0.017) among all influenza admissions; 2010 (55, 7.0%), 2011 (49, 6.2%), 2012 (74, 6.5%), 2013 (76, 7.3%), 2014 (84, 6.3%), 2015 (114, 8.4%), 2016 (79, 5.6%), 2017 (115, 6.6%), 2018 (79, 5.7%) and 2019 (29, 4.0%) respectively. On multivariate analysis, factors independently associated with nosocomial influenza cases were co-morbidities of congestive heart failure (AOR 1.47, 95%CI 1.16–1.86), renal disease (AOR 1.76, 95%CI 1.38–2.23), cerebrovascular disease (AOR 1.79, 95%CI 1.36–2.35), any malignancy (AOR 2.19, 95%CI 1.63–2.94) and influenza A (AOR 1.44, 95% 1.14–1.82). In contrast, chronic pulmonary disease (AOR 0.59, 95%CI 0.46–0.76) was less common in nosocomial influenza cases after adjusting for age, gender, ethnicity and admission year. On multivariable analysis, predictors of in-hospital 30 d mortality were age (AOR 1.04, 95%CI 1.03–1.05), Charlson score (AOR 1.18, 95%CI 1.13–1.24) and hospital-acquired influenza (AOR 1.57, 95%CI 1.04–2.37) after adjusting for gender, ethnicity, influenza subtypes and admission year. Conclusion: Annual influenza vaccination should be actively promoted not only for patients with chronic medical conditions but also for healthcare workers who nurse patients especially with low immunity.

Risk factors for hospital-acquired influenza A and patient characteristics: a matched case-control study

BackgroundWhile hospital-acquired influenza A results in an additional cost burden and considerable mortality in patients, its risk factors are unknown. We aimed to describe the characteristics of patients vulnerable to hospital-acquired influenza A and to identify its risk factors to assist clinicians control hospital-acquired infections and reduce the burden of treatment.MethodsA case-control study was conducted among hospitalized patients aged ≥18 years at a tertiary level teaching hospital during the 2018–2019 influenza A season. Patient data were retrieved from hospital-based electronic medical records. Hospital-acquired influenza A was defined as a case of influenza A diagnosed 7 days or more after admission, in a patient with no evidence of influenza A infection on admission. The controls without influenza A were selected among patients exposed to the same setting and time period. We identified risk factors using conditional logistic regression and described the characteristics of hospital-acquired influenza A by comparing the clinical data of infected patients and the controls.ResultsOf the 412 hospitalized patients with influenza A from all the departments in the study hospital, 93 (22.6%) cases were classified as hospital-acquired. The most common comorbidities of the 93 cases were hypertension (41.9%), coronary heart disease (21.5%), and cerebrovascular disease (20.4%). Before the onset of hospital-acquired influenza A, patients presented more lymphocytopenia (51.6% vs 35.5%, P = 0.027), hypoalbuminemia (78.5% vs 57.0%, P = 0.002), and pleural effusion (26.9% vs 9.7%, P = 0.002) than the matched controls. Infected patients also had longer hospital stays (18 days vs 14 days, P = 0.002), and higher mortality rates (10.8% vs 2.2%, P = 0.017) than the matched controls. Lymphocytopenia (odds ratio [OR]: 3.11; 95% confidence interval [CI]: 1.24–7.80; P = 0.016), hypoalbuminemia (OR: 2.24; 95% CI: 1.10–4.57; P = 0.027), and pleural effusion (OR: 3.09; 95% CI: 1.26–7.58; P = 0.014) were independently associated with hospital-acquired influenza A.ConclusionsLymphocytopenia, hypoalbuminemia and pleural effusion are independent risk factors that can help identify patients at high risk of hospital-acquired influenza A, which can extend hospital stay and is associated with a high mortality.