Healthcare-associated influenza in Canadian hospitals from 2006 to 2012

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

BACKGROUND

Hospital-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.

AIM

This 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.

METHODS

This 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.

RESULTS

Patients 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.

CONCLUSION

This 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.

Traditional definition of healthcare-associated influenza underestimates cases associated with other healthcare exposures in a population-based surveillance system

OBJECTIVE

To provide comprehensive population-level estimates of the burden of healthcare-associated influenza.

DESIGN

Retrospective cross-sectional study.

SETTING

US Influenza Hospitalization Surveillance Network (FluSurv-NET) during 2012-2013 through 2018-2019 influenza seasons.

PATIENTS

Laboratory-confirmed influenza-related hospitalizations in an 8-county catchment area in Tennessee.

METHODS

The incidence of healthcare-associated influenza was determined using the traditional definition (ie, positive influenza test after hospital day 3) in addition to often underrecognized cases associated with recent post-acute care facility admission or a recent acute care hospitalization for a noninfluenza illness in the preceding 7 days.

RESULTS

Among the 5,904 laboratory-confirmed influenza-related hospitalizations, 147 (2.5%) had traditionally defined healthcare-associated influenza. When we included patients with a positive influenza test obtained in the first 3 days of hospitalization and who were either transferred to the hospital directly from a post-acute care facility or who were recently discharged from an acute care facility for a noninfluenza illness in the preceding 7 days, we identified an additional 1,031 cases (17.5% of all influenza-related hospitalizations).

CONCLUSIONS

Including influenza cases associated with preadmission healthcare exposures with traditionally defined cases resulted in an 8-fold higher incidence of healthcare-associated influenza. These results emphasize the importance of capturing other healthcare exposures that may serve as the initial site of viral transmission to provide more comprehensive estimates of the burden of healthcare-associated influenza and to inform improved infection prevention strategies.

Comparison of 28-Day Mortality Between Hospital- and Community-Acquired Influenza Patients

Objective

This study aimed to compare 28-day mortality between patients have hospital-acquired influenza (HAI) and those have community-acquired influenza (CAI) during the 2017-2019 influenza seasons in a tertiary care center in İstanbul, Türkiye.

Materials and Methods

This retrospective cohort included all hospitalized patients who had confirmed influenza infection and were over 17 years old. HAI was defined as a case of influenza that tested negative in a PCR test or had no signs of influenza on admission but with a positive test result at any point after 72 hours of admission. CAI was defined as a case of influenza diagnosed within 72 hours of admission or before admission. The primary outcome was 28-day mortality after diagnosis. Biological sex, admission to the intensive care unit (ICU), presence of chronic obstructive pulmonary disease, cardiovascular and immunosuppressive comorbidities, influenza subtype, and other variables identified with univariate analyses (p<0.25) were entered into logistic regression analysis.

Results

During the study period, 92 (46%) of 201 hospitalized patients who tested positive for influenza were identified as HAI, and the rest (109) were identified as CAI. Univariate analysis showed no differences between survivors and non-survivors in patient characteristics, except non-survivors were more likely to have an ICU admission. The multivariable logistic regression analysis results showed that HAI was associated with 5.6-fold increased odds of mortality (95% confidence interval [CI]=1.6-19.3; p=0.006), after adjustment for age, gender, comorbidity, and ICU admission.

Conclusion

The results of this study revealed that patients who had HAI were more likely to die within 28 days compared to those who had CAI after controlling for key confounders. The high rate of HAI underscores the critical importance of robust infection control measures for hospital-acquired viral infections. Additional research and targeted interventions are necessary to improve the HAI prognosis.

Influenza Vaccination Behaviour of Healthcare Workers in Switzerland: A Cross-Sectional Study

Objectives: As no data are available regarding the influenza vaccination status of Swiss healthcare workers (HCW) in the ambulatory setting, this study aims to investigate their influenza vaccination behaviours.

Methods: We conducted an online survey using a four-item, semi-structured questionnaire to assess HCWs influenza vaccination coverage and behaviour. Associations between influenza vaccination status, age and language as well as recommendation behaviour and reasons for vaccination were assessed using descriptive statistics and logistic regression analyses.

Results: Of the 1057 completed questionnaires, 425 (40.2%) HCW were vaccinated and 632 (59.8%) not. 78.1% of the physicians and 47.3% pharmacists were vaccinated, compared to only 29.1% of the nurses, 24.3% pharmacy technicians and 13.0% medical practice assistants (MPA). There was a significant association between influenza vaccination status and HCW profession, age, language and how often an influenza vaccination recommendation was made.

Conclusion: Demographic factors seem to influence HCWs’ attitudes towards influenza vaccination, which in turn affects the prospect of them recommending the influenza vaccination. Diverse strategies might be necessary to encourage HCW to get vaccinated and hence, promote influenza vaccination.

Nosocomial acquisition of influenza is associated with significant morbidity and mortality: Results of a prospective observational study

BACKGROUND

Nosocomial acquisition of influenza is known to occur but the risk after exposure to a known case and the outcomes after acquisition are poorly defined.

METHODS

Prospective observational study of patients exposed to influenza from another patient in a multi-site healthcare organisation, with follow-up of 7 days or until discharge, and PCR-confirmation of symptomatic disease. Multivariable analysis was used to investigate association of influenza acquisition with high dependency unit/intensive care unit (HDU/ITU) admission and in-hospital mortality.

RESULTS

23/298 (7.7%) contacts of 11 cases were subsequently symptomatic and tested influenza-positive during follow-up. HDU/ITU admission was significantly higher in these secondary cases (6/23, 26%) compared to flu-negative contacts (20/275, 7.2%; p = 0.002). In-hospital mortality was significantly higher in secondary cases (5/23, 21.7%) compared to flu-negative contacts (11/275, 4%; p < 0.001). In multivariable analysis, age (OR 1.25 95% CI: 1.01-1.54, p = 0.02) and being a secondary case (OR 4.77, 95% CI: 1.63-13.9, p = 0.008) were significantly associated with HDU/ITU admission in contacts. Age (OR 1.00, 95% CI: 0.93-1.00, p = 0.02), being a secondary case after exposure to influenza (OR 3.81, 95% CI 1.09-13.3, p = 0.049) and co-morbidity (OR 1.29 per unit increment in the Charlson score, 95% CI 1.02-1.61, p = 0.03) were significantly associated with in-hospital mortality in contacts.

CONCLUSIONS

Nosocomial acquisition of influenza was significantly associated with increased risk of HDU/ITU admission and in-hospital mortality.

Vaccination policies for healthcare personnel: Current challenges and future perspectives

Healthcare personnel (HCP) are at occupational risk for acquisition of several vaccine-preventable diseases and transmission to patients. Vaccinations of HCP are justified to confer them immunity but also to protect susceptible patients and healthcare services from outbreaks, HCP absenteeism and presenteeism. Mandatory vaccination policies for HCP are increasingly adopted and achieve high and sustainable vaccination rates in short term. In this article we review the scientific evidence for HCP vaccination. We also address issues pertaining to vaccination policies for HCP and present the challenges of implementation of mandatory versus voluntary vaccination policies. Finally, we discuss the issue of mandatory vaccination of HCP against COVID-19.

Incidence of Influenza Virus Infection among Wroclaw's Healthcare Workers in Pre-COVID-19 2019-2020 Influenza Season Using Novel Flu SensDx Device

Background: Healthcare workers (HCWs) are more exposed to influenza infection, and the influenza vaccination is recommended each year, to reduce the risk of influenza infection and prevent influenza transmission. This study is a cross-sectional study and the objectives were to determine the rate of influenza virus infection among HCWs in the 2019−2020 influenza season. Methods: Between January and March 2020, a survey was carried out in 2 hospitals and 15 primary health-care settings (PHCS) in Wroclaw (Poland). The novel point-of-care testing Flu SensDx device was used, which detects the M1 protein of the influenza virus using electrochemical impedance spectroscopy from biological material (throat/nasal swabs). Results: A total of 150 samples were collected. The majority of participating HCWs by profession were 83 physicians (55.3%) and half (51.3%) of the participating HCWs worked in PHCS. Influenza vaccination coverage was 61.3% in 2019−2020 and 46.0% in the 2018−2019 season for all participants. Of the participating HCWs, 44.0% were positive tested by the Flu SensDx device. There were no statistically significant differences among the positive tested HCWs, their influenza immunization history, and the presence of symptoms of influenza-like illness (p > 0.05). Conclusion: Although the results of the present study suggest that influenza vaccination does not reduce the frequency of influenza virus detection by Flu SensDx testing in the HCWs participants, larger studies are needed to estimate the incidence of influenza virus infection among HCWs to understand the underlying mechanism and fine-tune policies aimed at reducing nosocomial infections.

Influenza Vaccination Programs for Healthcare Personnel: Organizational Issues and Beyond

Healthcare personnel (HCP) are a high priority group for influenza vaccination aiming to protect them but also to protect vulnerable patients and healthcare services from healthcare-associated influenza and HCP absenteeism. Multi-component influenza vaccination programs targeting behavioral, organizational, and administrative barriers are critical, if influenza vaccination rates among HCP are to be raised on a sustained basis. Mandatory influenza vaccination policy is the only single intervention that can achieve high and sustainable vaccination rates in HCP in short term. In this article, we provide an overview of issues pertaining to influenza vaccination of HCP, with an emphasis on organizational issues of influenza vaccination programs.

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

OBJECTIVE

To estimate population-based rates and to describe clinical characteristics of hospital-acquired (HA) influenza.

DESIGN

Cross-sectional study.

SETTING

US Influenza Hospitalization Surveillance Network (FluSurv-NET) during 2011-2012 through 2018-2019 seasons.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Determinants for hospitalisations, intensive care unit admission and death among 20,293 reported COVID-19 cases in Portugal, March to April 2020

Background

Determinants of hospitalisation, intensive care unit (ICU) admission and death are still unclear for COVID-19. Few studies have adjusted for confounding for different clinical outcomes including all reported cases within a country.

Aim

We used routine surveillance data from Portugal to identify risk factors for severe COVID-19 outcomes, and to support risk stratification, public health interventions, and planning of healthcare resources.

Methods

We conducted a retrospective cohort study including 20,293 laboratory-confirmed cases of COVID-19 reported between 1 March and 28 April 2020 through the national epidemiological surveillance system. We calculated absolute risk, relative risk (RR) and adjusted relative risk (aRR) to identify demographic and clinical factors associated with hospitalisation, ICU admission and death using Poisson regressions.

Results

Increasing age (≥ 60 years) was the major determinant for all outcomes. Age ≥ 90 years was the strongest determinant of hospital admission (aRR: 6.1), and 70–79 years for ICU (aRR: 10.4). Comorbidities of cardiovascular, immunodeficiency, kidney and lung disease (aRR: 4.3, 2.8, 2.4, 2.0, respectively) had stronger associations with ICU admission, while for death they were kidney, cardiovascular and chronic neurological disease (aRR: 2.9, 2.6, 2.0).

Conclusions

Older age was the strongest risk factor for all severe outcomes. These findings from the early stages of the COVID-19 pandemic support risk-stratified public health measures that should prioritise protecting older people. Epidemiological scenarios and clinical guidelines should consider this, even though under-ascertainment should also be considered.

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

BACKGROUND

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.

METHODS

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).

RESULTS

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.

CONCLUSIONS

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.

Prophylaxis and treatment of influenza: options, antiviral susceptibility, and existing recommendations

Influenza viruses of types A and B attack 5-10% of adults and 20-30% of children, thereby causing millions of acute respiratory infections in Germany annually. A significant number of these infections are associated with complications such as pneumonia and bacterial superinfections that need hospitalization and might lead to death. In addition to vaccines, drugs were developed that might support influenza prevention and that can be used to treat influenza patients. The timely application of anti-influenza drugs can inhibit virus replication, help reduce and shorten the symptoms, and prevent death as well as virus transmission. This review concisely describes the mechanism of action, the potential for prophylactic and therapeutic use, and the knowledge on resistance of anti-influenza drugs approved today. However, the main aim is to give an overview on the recommendations available in Germany for the proper use of these drugs. In doing so, the recommendations published in statements and guidelines of medical societies as well as the German influenza pandemic preparedness plan are summarized with the consideration of specific circumstances and groups of patients.

Burden of noninfluenza respiratory viral infections in adults admitted to hospital: analysis of a multiyear Canadian surveillance cohort from 2 centres

BACKGROUND:

Data on the outcomes of noninfluenza respiratory virus (NIRV) infections among hospitalized adults are lacking. We aimed to study the burden, severity and outcomes of NIRV infections in this population.

METHODS:

We analyzed pooled patient data from 2 hospital-based respiratory virus surveillance cohorts in 2 regions of Canada during 3 consecutive seasons (2015/16, 2016/17, 2017/18; n = 2119). We included patients aged ≥ 18 years who developed influenza-like illness or pneumonia and were hospitalized for management. We included patients confirmed positive for ≥ 1 virus by multiplex polymerase chain reaction assays (respiratory syncytial virus [RSV], human rhinovirus/enterovirus (hRV), human coronavirus (hCoV), metapneumovirus, parainfluenza virus, adenovirus, influenza viruses). We compared patient characteristics, clinical severity conventional outcomes (e.g., hospital length-of stay, 30-day mortality) and ordinal outcomes (5 levels: discharged, receiving convalescent care, acute ward or intensive care unit [ICU] care and death) for patients with NIRV infections and those with influenza.

RESULTS:

Among 2119 adults who were admitted to hospital, 1156 patients (54.6%) had NIRV infections (hRV 14.9%, RSV 12.9%, hCoV 8.2%) and 963 patients (45.4%) had influenza (n = 963). Patients with NIRVs were younger (mean 66.4 [standard deviation 20.4] yr), and more commonly had immunocompromising conditions (30.3%) and delay in diagnosis (median 4.0 [interquartile range (IQR) 2.0–7.0] days). Overall, 14.6% (12.4%–19.5%) of NIRV infections were acquired in hospital. Admission to ICU (18.2%, median 6.0 [IQR 3.0–13.0] d), hospital length-of-stay (median 5.0 [IQR 2.0–10.0] d) and 30-day mortality (8.4%; RSV 9.5%, hRV 6.6%, hCoV 9.2%) and the ordinal outcomes were similar for patients with NIRV infection and those with influenza. Age > 60 years, immunocompromised state and hospital-acquired viral infection were associated with worse outcomes. The estimated median cost per acute care admission was $6000 (IQR $2000–$16 000).

INTERPRETATION:

The burden of NIRV infection is substantial in adults admitted to hospital and associated outcomes may be as severe as for influenza, suggesting a need to prioritize therapeutics and vaccines for at-risk people.

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.

Effectiveness of a Mobile-Based Influenza-Like Illness Surveillance System (FluMob) Among Health Care Workers: Longitudinal Study

BACKGROUND

Existing studies have suggested that internet-based participatory surveillance systems are a valid sentinel for influenza-like illness (ILI) surveillance. However, there is limited scientific knowledge on the effectiveness of mobile-based ILI surveillance systems. Previous studies also adopted a passive surveillance approach and have not fully investigated the effectiveness of the systems and their determinants.

OBJECTIVE

The aim of this study was to assess the efficiency of a mobile-based surveillance system of ILI, termed FluMob, among health care workers using a targeted surveillance approach. Specifically, this study evaluated the effectiveness of the system for ILI surveillance pertaining to its participation engagement and surveillance power. In addition, we aimed to identify the factors that can moderate the effectiveness of the system.

METHODS

The FluMob system was launched in two large hospitals in Singapore from April 2016 to March 2018. A total of 690 clinical and nonclinical hospital staff participated in the study for 18 months and were prompted via app notifications to submit a survey listing 18 acute respiratory symptoms (eg, fever, cough, sore throat) on a weekly basis. There was a period of study disruption due to maintenance of the system and the end of the participation incentive between May and July of 2017.

RESULTS

On average, the individual submission rate was 41.4% (SD 24.3%), with a rate of 51.8% (SD 26.4%) before the study disruption and of 21.5% (SD 30.6%) after the disruption. Multivariable regression analysis showed that the adjusted individual submission rates were higher for participants who were older (<30 years, 31.4% vs 31-40 years, 40.2% [P<.001]; 41-50 years, 46.0% [P<.001]; >50 years, 39.9% [P=.01]), ethnic Chinese (Chinese, 44.4% vs non-Chinese, 34.7%; P<.001), and vaccinated against flu in the past year (vaccinated, 44.6% vs nonvaccinated, 34.4%; P<.001). In addition, the weekly ILI incidence was 1.07% on average. The Pearson correlation coefficient between ILI incidence estimated by FluMob and that reported by Singapore Ministry of Health was 0.04 (P=.75) with all data and was 0.38 (P=.006) including only data collected before the study disruption. Health care workers with higher risks of ILI and influenza such as women, non-Chinese, allied health staff, those who had children in their households, not vaccinated against influenza, and reported allergy demonstrated higher surveillance correlations.

CONCLUSIONS

Mobile-based ILI surveillance systems among health care workers can be effective. However, proper operation of the mobile system without major disruptions is vital for the engagement of participants and the persistence of surveillance power. Moreover, the effectiveness of the mobile surveillance system can be moderated by participants' characteristics, which highlights the importance of targeted disease surveillance that can reduce the cost of recruitment and engagement.

Dynamics of nosocomial parainfluenza virus type 3 and influenza virus infections at a large German University Hospital between 2012 and 2019

Nosocomial virus infections cause significant morbidity and mortality. Besides influenza viruses, the disease burden of parainfluenza virus type 3 (PIV-3) is comparatively high among hospitalized patients and severe disease courses can occur. PIV-3 showed the highest rates of nosocomial infections of a panel of respiratory viruses. Therefore, a retrospective observational study was conducted among patients with either PIV-3 or influenza viruses, which served as reference pathogen. The aim was to compare the seasonal dynamics and clinical characteristics of nosocomial infections with these highly transmittable viruses. Nosocomial infection occurred in 15.8% (n = 177) of all influenza cases, mainly in the first half of a season. About 24.3% (n = 104) of the PIV-3 cases were nosocomial and occurred mainly in the second half of a season. Both nosocomial rates of influenza and nosocomial rates of PIV-3 varied between the seasons. Community acquired and nosocomial cases differed in underlying medical conditions and immunosuppression. Knowledge of the baseline rates of nosocomial infections could contribute to the implementation of appropriate infection control measures.

Description of an influenza outbreak in a French university hospital and risk factors of nosocomial influenza

Our objective was to evaluate risk factors of nosocomial influenza (NI) in an university hospital during the 2015/2016 influenza season. All hospitalized patients with influenza-like illness associated with laboratory confirmation by polymerase chain reaction were included in a prospective observational study. We identified 44 cases (19%) of NI among the 233 cases of influenza: 38/178 (21%) in adults and 6/55 (11%) in children. Among adults, hospitalization in a double or multi-occupancy room was independently associated with NI (adjusted Odds Ratio, 3.42; 95% CI, 1.29-9.08; p = 0.013). The results of the study underline the importance of single room to prevent NI.

Infection prevention and control measures in practices of the Swiss sentinel network during seasonal influenza epidemics

Background

There are limited data on the transmission of influenza in the context of primary care practices, despite the fact that a significant proportion of the population consult their primary care physician for an influenza-like illness every year.

Aim

To describe the use of influenza prevention and control methods in private practices of the Swiss sentinel network.

Methods

This online cross-sectional survey collected data about infection prevention and control measures in the 166 private practices of the Swiss sentinel surveillance network during the 2018–2019 influenza season. Questions pertained to the practice setting, infection prevention and control recommendations, influenza vaccination status of the physicians and their staff, adhesion to hand hygiene, and mask wearing.

Findings

Among the 122 practices that answered (response rate 73.5%), 90.2% of the responding physicians had been vaccinated themselves, and 46.7% (56/120) estimated that their staff vaccination coverage was >60%, although it was offered to employees in all practices. Most practices (N=68, 55.7%) had no specific recommendations for their staff concerning mask wearing. Most physicians reported washing or disinfecting their hands before examining a patient (N=91, 74.6%), after examination (N=110, 90.2%) and before a medical procedure (N=112, 91.8%). However, this rate was lower for arrival at the practice (N=78, 63.9%) and leaving the practice (N=83, 68.0%).

Conclusion

Most physicians in the Swiss sentinel surveillance network have been vaccinated themselves. However, the vaccination rates among their staff are low, despite vaccine availability. Hand hygiene measures were also suboptimal. These results warrant further efforts to implement infection prevention and control measures in the ambulatory setting.

Quantifying influenza exposure within California hospitals and nursing homes using administrative data

Influenza acquisition occurs in hospitals and nursing homes (NHs), highlighting the need for infection prevention. We used administrative data to quantify influenza exposure and facility-onset influenza rates for California hospitals and NHs during the 2015-2016 influenza season. Higher facility-onset influenza rates were identified in NHs compared with hospitals, despite fewer influenza exposure-days in NHs. Validation of administrative data are needed.

Development of an Ordinal Scale Treatment Endpoint for Adults Hospitalized With Influenza

BACKGROUND

An obstacle in influenza therapeutics development is the lack of clinical endpoints, especially in hospitalized patients. A single time-point binary outcome measure is limited by patients' diverse clinical trajectories and low event rates.

METHODS

A 6-point ordinal scale with ascending clinical status severity (scoring: discharged; subacute care; acute care without/with respiratory failure; intensive care unit [ICU]; death) was proposed to study outcomes of adults hospitalized with influenza. Individual patient data from 2 active surveillance cohorts' datasets (2015/2016-2017/2018; Edmonton, Hong Kong) was used for evaluation. The impact of neuraminidase inhibitor (NAI) treatment on longitudinal ordinal outcome changes over 30 days was analyzed using mixed-effects ordinal logistic regression and group-based trajectory models.

RESULTS

Patient (n = 1226) baseline characteristics included age (mean 68.0 years), virus-type (A 78.1%, B 21.9%), respiratory failure (57.2%), ICU admittance (14.4%), and NAI treatment within 5 days of illness (69.2%). Outcomes at 30 days included discharged (75.2%), subacute care (13.7%), acute care (4.5%), and death (6.6%). Two main clinical trajectories were identified, predictive by baseline scoring (mean ± SD, 4.3 ± 0.6 vs 3.5 ± 0.6, P < .001). Improved outcomes with NAI treatment within 5 days were indicated by significantly lower clinical status scores over time (unadjusted odds ratio [OR], 0.53; 95% confidence interval [CI], .41-.69; P < .001; adjusted OR, 0.62; 95% CI, .50-.77; P < .001, for baseline score, age, and within-patient correlations). In subanalysis, influenza vaccination was also associated with lower scores (adjusted OR, 0.67; 95% CI, .50-.90; P = .007). Analyses of binary endpoints showed insignificant results.

CONCLUSIONS

The ordinal outcome scale is a potentially useful clinical endpoint for influenza therapeutic trials, which could account for the diverse clinical trajectories of hospitalized patients, warranting further development.

Influenza vaccine uptake and attitudes of healthcare workers in Ireland

BACKGROUND

Influenza vaccination uptake by Irish healthcare workers remains sub-optimal despite local initiatives to increase it.

AIMS

To investigate hospital workers' attitudes to influenza vaccination and how this influenced their decisions about vaccination.

METHODS

A questionnaire survey of Irish hospital workers, measuring uptake of and attitudes to influenza vaccination.

RESULTS

There were 747 responders, of whom 361 (48%) reported having received influenza vaccination. Attitudes predicting vaccination uptake included a belief that vaccination would protect family members (P < 0.0005, CI 1.191-1.739), a perception of susceptibility to 'flu (P < 0.0005, CI 1.182-1.685), a belief that all healthcare workers should be vaccinated (P < 0.005, CI 1.153-1.783), perceived ease of getting 'flu vaccination at work (P < 0.0005, CI 1.851-2.842) and encouragement by line managers (P < 0.05, CI 1.018-1.400). Attitudes negatively associated with vaccination uptake included fear of needles (P < 0.05, CI 0.663-0.985) and a belief that vaccination would cause illness (P < 0.0005, CI 0.436-0.647). Medical staff were significantly more likely to be vaccinated. Healthcare students were least likely to be vaccinated (P < 0.0005).

CONCLUSION

Addressing specific barriers to influenza vaccination in healthcare workers may improve uptake.

Are healthcare workers more likely than the general population to consult in primary care for an influenza-like illness? Results from a case-control study

Background

Healthcare workers are at increased risk of contracting influenza. However, existing studies do not differentiate professional categories or domains of the healthcare system that are most at risk.

Methods

This case‐control study compared proportions of patients with professional activity in the healthcare system between cases consulting their primary care physician for an influenza‐like illness (ILI) and controls from the general patient population of the same practices of the Swiss sentinel network. Influenza was confirmed by rRT‐PCR in a subset of practices. Analysis used a mixed logistic regression model, including age and sex as potential confounders.

Results

During the 2018/2019 influenza surveillance season, out of 4287 ILI cases and 28 561 controls reported in 168 practices, 235 (5.5%), respectively 872 (3.1%), were active in the healthcare system. After adjustment, being active in health care increased the odds of consulting for an ILI (OR 1.66, 95% CI 1.40‐1.97). The association was strongest for physicians and nursing aides. In terms of work setting, odds of consulting for ILI were increased for professionals of almost all healthcare settings except home‐based care.

Conclusion

Individuals active in the healthcare system were more likely to consult their primary care physician for an influenza‐like illness than for another reason, compared with individuals not active in the healthcare system. These results warrant further efforts to understand influenza transmission in the healthcare system at large.

Utility of Healthcare System-Based Interventions in Improving the Uptake of Influenza Vaccination in Healthcare Workers at Long-Term Care Facilities: A Systematic Review

Healthcare workers (HCWs) in long-term care facilities (LTCFs) can represent a source of influenza infection for the elderly. While flu vaccination coverage (VC) is satisfactory in the elderly, HCWs are less likely to be vaccinated. There is no definitive evidence on which types of healthcare system-based interventions at LTCFs would be more useful in improving the vaccination uptake among HCWs. We performed a systematic review in different databases (Pubmed, Cochrane Database of Systematic Reviews, Health Evidence, Web of Science, Cinahl) to provide a synthesis of the available studies on this topic. Among the 1177 articles screened by their titles and abstracts, 27 were included in this review. Most of the studies reported multiple interventions addressed to improve access to vaccination, eliminate individual barriers, or introduce policy interventions. As expected, mandatory vaccinations seem to be the most useful intervention to increase the vaccination uptake in HCWs. However, our study suggests that better results in the vaccination uptake in HCWs were obtained by combining interventions in different areas. Educational campaigns alone could not have an impact on vaccination coverage. LTCFs represent an ideal setting to perform preventive multi-approach interventions for the epidemiological transition toward aging and chronicity.

Intermittent occurrence of health care-onset influenza cases in a tertiary care facility during the 2017-2018 flu season

Health care-onset influenza (HOI) poses a major risk for hospitalized patients. During the 2017-2018 season, 37 HOI cases out of 382 inpatients (9.7%) with influenza were detected in a tertiary care hospital. HOI and community-onset influenza cases peaked simultaneously, and employee absenteeism was delayed by 1 month. A HOI to community-onset influenza case-comparison revealed associations with placement in rehabilitation, leukocytosis, health care-associated infections, and elevated mortality rates. Interventions should be selected based on the epidemiology of influenza occurrence.

Risk factors and clinical characteristics of patients with nosocomial influenza A infection

Influenza is a public health burden, responsible for more than half a million deaths worldwide each year and explosive outbreaks in-hospital care units. At present, little is known about clinical characteristics and outcomes with nosocomial influenza infection. To assess clinical characteristics and outcome between nosocomial and community-acquired (CA) influenza in a tertiary care hospital. A retrospective study of hospitalized patients in a French tertiary care hospital from 1st December 2016 to 28th February 2017 for flu-illness confirmed by reverse transcription PCR. Overall, 208 patients with laboratory-confirmed influenza were included; whose 49 nosocomial cases (23.6%). Patients with nosocomial influenza were significantly older (79.1 ± 15.5 vs 64.8 ± 31.1 years old; P = .003), with the more rapidly fatal disease (10.2% vs 1.3%; P = .0032). They had a less respiratory failure (8.2% vs 21.4%; P = .036) but had a longer length of hospitalization (47.3 vs 12.9 days; P < .001) than patients with CA influenza. During this influenza outbreak, 19 patients died (9.1%), none of them were vaccinated. Effective control of outbreaks in hospital facilities is challenging. Hospitalized patients are vulnerable to nosocomial Influenza infections that can increase the length of stay and be responsible for the death. Surveillance and early warning systems should be encouraged. Vaccination policies in conjunction with isolation measures and better hand hygiene could reduce virus spreading in hospitals.

Recommended hospital preparations for future cases and outbreaks of novel influenza viruses

Introduction: Seasonal influenza epidemics and periodic pandemics are important causes of morbidity and mortality. Influenza transmits predominantly by respiratory droplets and fomites but opportunistic airborne transmission may occur in the hospital setting due to overcrowding, poor compliance with infection control measures, and performance of aerosol-generating procedures.Areas covered: This article reviews the risk factors of nosocomial influenza outbreaks and discusses clinical, diagnostic, and treatment aspects of seasonal and avian influenza to facilitate hospital preparations for future influenza outbreaks. Literature search was conducted through PubMed of relevant peer-reviewed full papers in English journals with inclusion of relevant publications by the WHO and US CDC.Expert opinion: Accurate and rapid identification of an influenza outbreak is important to facilitate patient care and prevent nosocomial transmission. Timely treatment with a neuraminidase inhibitor (NAI) for adults hospitalized with severe influenza is associated with lower mortality and better clinical outcomes. Baloxavir, a polymerase endonuclease inhibitor, offers a new treatment alternative and its role in combination with NAI for treatment of severe influenza is being investigated. High-dose systemic corticosteroids are associated with worse outcomes in patients with severe influenza. It is important to develop more effective antiviral and immuno-modulating therapies for the treatment of influenza infections.

Pregnancy as a risk factor for severe influenza infection: an individual participant data meta-analysis

BACKGROUND

WHO identifies pregnant women to be at increased risk for severe outcomes from influenza virus infections and recommends that they be prioritized for influenza vaccination. The evidence supporting this, however, is inconsistent. Ecologic studies in particular suggest more severe outcomes from influenza infection during pregnancy than studies based on individual patient data. Individual studies however may be underpowered and, as reported in a previous systematic review, confounding factors could not be adjusted for. We therefore conducted an individual participant data meta-analysis to assess the risk for severe outcomes of influenza infection in pregnant women while adjusting for other prognostic factors.

METHODS

We contacted authors of studies included in a recently published systematic review. We pooled the individual participant data of women of reproductive age and laboratory confirmation of influenza virus infection. We used a generalized linear mixed model and reported odds ratios (OR) and 95% confidence intervals (CI).

RESULTS

A total of 33 datasets with data on 186,656 individuals were available, including 36,498 eligible women of reproductive age and known pregnancy status. In the multivariable model, pregnancy was associated with a 7 times higher risk of hospital admission (OR 6.80, 95%CI 6.02-7.68), among patients receiving medical care as in- or outpatients, pregnancy was associated with a lower risk of admission to intensive care units (ICU; OR 0.57, 95%CI 0.48-0.69), and was not significantly associated with death (OR 1.00, 95%CI 0.75-1.34).

CONCLUSIONS

Our study found a higher risk of influenza associated hospitalization among pregnant women as compared to non-pregnant women. We did not find a higher mortality rate or higher likelihood of ICU admission among pregnant women who sought medical care. However, this study did not address whether a true community based cohort of pregnant women is at higher risk of influenza associated complications.

Nosocomial outbreak of influenza A H3N2 in an inpatient oncology unit related to health care workers presenting to work while ill

Objective

To describe an outbreak of influenza A in an oncology unit, highlighting infection control methods implemented, and examining reasons health care workers (HCWs) present to work with influenza-like illness (ILI).

Methods

Confirmed cases were defined by the presence of ILI and a positive nasopharyngeal polymerase chain reaction swab for influenza A H3. Probable cases were defined as exposed HCWs with ILI who were unavailable for polymerase chain reaction testing. Infection prevention measures included closing the ward for new admissions, oseltamivir prophylaxis for all exposed groups, and dismissal from work of HCWs with ILI until resolution of symptoms. An anonymous survey of the cases in our HCWs was conducted to better elucidate reasons behind presenteeism.

Results

Over the course of 8 days (November 16, 2017, to November 22, 2017), influenza was diagnosed in 7 of 10 inpatients on the oncology ward, 16 HCWs (14 confirmed, 2 probable), and 2 visitors. The suspected index case was an HCW. Of the surveyed HCWs, 64% presented to work despite feeling ill (ie, presenteeism). The most common reason was “sense of duty as a health care worker.”

Conclusions

This nosocomial outbreak of influenza highlights the challenges of protecting inpatients from viral respiratory tract infections. HCWs and patient visitors with ILI should avoid work or visiting until resolution of peak respiratory symptoms and adhere to strict respiratory etiquette.

Influenza virus RNA recovered from droplets and droplet nuclei emitted by adults in an acute care setting

Transmission in hospital settings of seasonal influenza viruses and novel agents such as the Middle East respiratory syndrome coronavirus (MERS-CoV) is well-described but poorly understood. The characterization of potentially infectious bio-aerosols in the healthcare setting remains an important yet ill-defined factor in the transmission of respiratory viruses. Empiric data describing the distribution of bio-aerosols enable discernment of potential exposure risk to respiratory viruses. We sought to determine the distribution of influenza virus RNA emitted into the air by participants with laboratory-confirmed influenza, and whether these emissions had the potential to reach healthcare workers' breathing zones. Two-stage cyclone bio-aerosol samplers from the Centers for Disease Control and Prevention - National Institute for Occupational Safety and Health were placed 0.5-1.0 m (near field) and 2.1-2.5 m (far field) from infected patient participants, as well as in the corridor immediately outside their rooms. In addition, healthcare worker participants providing care to infected participants were recruited to wear a polytetrafluoroethylene (PTFE) filter cassette in their breathing zones. Viral RNA was detected from the air emitted by 37.5% of the 16 participants infected with influenza virus and distributed both in near and far fields and in all tested particle sizes (<1 µm, 1-4 µm, and >4 µm). Viral RNA was recovered in droplet nuclei and beyond 1 m from naturally-infected participants in the healthcare setting and from the breathing zone of one healthcare worker. There was no correlation between patient participant nasal viral load and recovery of viral RNA from the air, and we did not identify any significant association between RNA detection from the air and patient demographics or clinical presentation. A more substantial study is required to identify patient determinants of virus emission into the air and delineate implications for evidence-based policy for prevention and control.

Hospital-acquired influenza in an Australian tertiary Centre 2017: a surveillance based study

Background

In 2017, Australia experienced its highest levels of influenza virus activity since the 2009 pandemic. This allowed detailed comparison of the characteristics of patients with community and hospital-acquired influenza, and infection control factors that contributed to influenza spread.

Methods

A surveillance based study was conducted on hospitalised patients with laboratory-confirmed influenza at the Canberra Hospital during April–October 2017. Differences between the hospital-acquired and community-acquired patient characteristics and outcomes were assessed by univariate analysis. Epidemiologic curves were developed and cluster distribution within the hospital was determined.

Results

Two hundred and ninety-two patients were included in the study. Twenty-eight (9.6%) acquired influenza in hospital, representing a higher proportion than any of the previous 5 years (range 0.9–5.8%). These patients were more likely to have influenza A (p = 0.021), had higher rates of diabetes (p = 0.015), malignancy (p = 0.046) and chronic liver disease (p = 0.043). Patients acquiring influenza in hospital met clinical criteria for influenza like illness in 25% of cases, compared with 64.4% for community-acquired cases (p < 0.001). Hospital-acquired influenza cases occurred in two distinct clusters. Patients were moved an average of 5 times after diagnosis. Mean length of stay following diagnosis was 13 days compared to 5 days for community-acquired cases (p < 0.001). Of the patients with hospital-acquired influenza, 22 were in shared rooms during their incubation period and 9 were not isolated in single rooms following diagnosis. Treatment was initiated within the recommended 48 h period following symptom onset for 62.5% of hospital-acquired cases compared with 39.8% of community-acquired cases (p = 0.033).

Conclusions

Our results show that clinical presentation differed between patients with hospital-acquired influenza compared with those who acquired influenza in the community. Cases occurred in two clusters suggesting intra-hospital transmission rather than random importation from the community, highlighting the importance of infection control measures to limit influenza spread. Patients with hospital-acquired influenza may present without classical features of an influenza-like illness and this should promote earlier diagnostic testing and isolation to limit spread. Movement of patients after diagnosis is likely to facilitate spread within the hospital.

Clinical Practice Guidelines by the Infectious Diseases Society of America: 2018 Update on Diagnosis, Treatment, Chemoprophylaxis, and Institutional Outbreak Management of Seasonal Influenzaa

These clinical practice guidelines are an update of the guidelines published by the Infectious Diseases Society of America (IDSA) in 2009, prior to the 2009 H1N1 influenza pandemic. This document addresses new information regarding diagnostic testing, treatment and chemoprophylaxis with antiviral medications, and issues related to institutional outbreak management for seasonal influenza. It is intended for use by primary care clinicians, obstetricians, emergency medicine providers, hospitalists, laboratorians, and infectious disease specialists, as well as other clinicians managing patients with suspected or laboratory-confirmed influenza. The guidelines consider the care of children and adults, including special populations such as pregnant and postpartum women and immunocompromised patients.

Clinical Practice Guidelines by the Infectious Diseases Society of America: 2018 Update on Diagnosis, Treatment, Chemoprophylaxis, and Institutional Outbreak Management of Seasonal Influenzaa

These clinical practice guidelines are an update of the guidelines published by the Infectious Diseases Society of America (IDSA) in 2009, prior to the 2009 H1N1 influenza pandemic. This document addresses new information regarding diagnostic testing, treatment and chemoprophylaxis with antiviral medications, and issues related to institutional outbreak management for seasonal influenza. It is intended for use by primary care clinicians, obstetricians, emergency medicine providers, hospitalists, laboratorians, and infectious disease specialists, as well as other clinicians managing patients with suspected or laboratory-confirmed influenza. The guidelines consider the care of children and adults, including special populations such as pregnant and postpartum women and immunocompromised patients.

[Influenza infection: An update for clinicians]

Lower respiratory infections remain the deadliest communicable disease in the world. Influenza infections are particularly involved, whether intrinsically, or more frequently, by promoting bacterial infections and superinfections. The flu is also responsible for the decompensation of many comorbidities and could lead to some myocardial infarction and stroke. The effect of antiviral therapies is limited but preventives measures, such as vaccination, remain a major public health issue. The flu is a major challenge at all levels and all times, from vaccine prevention, to the recognition of atypical forms, and the early management of bacterial complications.

The potential economic value of influenza vaccination for healthcare workers in The Netherlands

Background

Despite the clinical evidence, influenza vaccination coverage of healthcare workers remains low. To assess the health economic value of implementing an influenza immunization program among healthcare workers (HCW) in University Medical Centers (UMCs) in the Netherlands, a cost‐benefit model was developed using a societal perspective.

Methods/Patients

The model was based on a trial performed among all UMCs in the Netherlands that included both hospital staff and patients admitted to the pediatrics and internal medicine departments. The model structure and parameters estimates were based on the trial and complemented with literature research, and the impact of uncertainty explored with sensitivity analyses.

Results

In a base‐case scenario without vaccine coverage, influenza‐related annual costs were estimated at € 410 815 for an average UMC with 8000 HCWs and an average occupancy during the influenza period of 6000 hospitalized patients. Of these costs, 82% attributed to the HCWs and 18% were patient‐related. With a vaccination coverage of 15.47%, the societal program’s savings were € 2861 which corresponds to a saving of € 270.53 per extended hospitalization. Univariate sensitivity analyses show that the results are most sensitive to changes in the model parameters vaccine effectiveness in reducing influenza‐like illness (ILI) and the vaccination‐related costs.

Conclusion

In addition to the decreased burden of patient morbidity among hospitalized patients, the effects of the hospital immunization program slightly outweigh the economic investments. These outcomes may support healthcare policymakers’ recommendations about the influenza vaccination program for healthcare workers.

Nosocomial influenza: encouraging insights and future challenges

PURPOSE OF REVIEW

The prevalence and incidence of viral nosocomial influenza infections in healthcare settings are underestimated. Nosocomial influenza outbreaks are frequent, and control remains challenging in acute care and long-term healthcare settings. This review examines recent publications on the determinants of nosocomial influenza prevention and control.

RECENT FINDINGS

Nosocomial influenza outbreaks occur in various healthcare settings, especially among the frail and elderly. The correct diagnosis is commonly missed because a substantial proportion of asymptomatic cases can transmit infections. Rapid diagnosis will facilitate rapid identification of cases and the implementation of control measures but needs confirmation in some circumstances, such as the description of transmission chains. Links between patients and healthcare personnel (HCP) have been well explored by phylogenetic virus characterization and need additional refinement and study. The preventive role of HCP vaccination in influenza incidence among patients should be investigated further in various settings to take into account different strategies for vaccination (i.e. voluntary or mandatory vaccination policies). Indeed, in Europe, influenza vaccination remains modest, whereas in North America hospitals and some states and provinces are now mandating influenza vaccination among HCP. The variability of vaccine effectiveness by seasonal epidemics is also an important consideration for control strategies.

SUMMARY

When influenza cases occur in the community, the risk of transmission and nosocomial cases increase in healthcare settings requiring vigilance among staff. Surveillance and early warning systems should be encouraged. Outbreak control needs appropriate identification of cases and transmission chains, and rapid implementation of control measures. Vaccination policies in conjunction with appropriate infection control measures could reduce virus spreading in hospitals. HCP vaccination coverage must be improved.

Mandatory influenza vaccination for all healthcare personnel: a review on justification, implementation and effectiveness

PURPOSE OF REVIEW

As healthcare-associated influenza is a serious public health concern, this review examines legal and ethical arguments supporting mandatory influenza vaccination policies for healthcare personnel, implementation issues and evidence of effectiveness.

RECENT FINDINGS

Spread of influenza from healthcare personnel to patients can result in severe harm or death. Although most healthcare personnel believe that they should be vaccinated against seasonal influenza, the Centers for Disease Control and Prevention (CDC) report that only 79% of personnel were vaccinated during the 2015-2016 season. Vaccination rates were as low as 44.9% in institutions that did not promote or offer the vaccine, compared with rates of more than 90% in institutions with mandatory vaccination policies. Policies that mandate influenza vaccination for healthcare personnel have legal and ethical justifications. Implementing such policies require multipronged approaches that include education efforts, easy access to vaccines, vaccine promotion, leadership support and consistent communication emphasizing patient safety.

SUMMARY

Mandatory influenza vaccination for healthcare personnel is a necessary step in protecting patients. Patients who interact with healthcare personnel are often at an elevated risk of complications from influenza. Vaccination is the best available strategy for protecting against influenza and evidence shows that institutional policies and state laws can effectively increase healthcare personnel vaccination rates, decreasing the risk of transmission in healthcare settings. There are legal and ethical precedents for institutional mandatory influenza policies and state laws, although successful implementation requires addressing both administrative and attitudinal barriers.

Definition of healthcare-associated influenza: A review and results from an international survey

Aim

To describe definitions of healthcare‐associated influenza (HAI) in recent literature and in hospitals participating in a survey of Society for Healthcare Epidemiology of America (SHEA) Research Network (SRN) members.

Method

A review with PubMed search was undertaken to retrieve articles published between 2008 and 2016, focusing on the subject headings “influenza, human” and “cross infection.” Definitions of clinical influenza‐like illness (ILI) and HAI were identified. An invitation to participate in the survey was sent to 218 SRN members via email.

Results

Of 75 articles on HAI included in the review, 30 presented a standardized definition of clinical ILI based on fever (100%), cough (80%), and sore throat (70%). Forty studies (53%) contained a standardized HAI definition, grounded on threshold delay from admission in 29 of them, this delay ranging from 48 to 196 hour (median: 72 hour). Fifty‐five SRN members responded to the survey, with a standardized definition of HAI adopted by 76% of them. This definition was based on clinical features for 24%, virological features for 31%, and both for 45%. Fever (mean threshold: 38.0°C) was part of the definition for 82%. The features required most frequently in the clinical definition were cough (46%) and sore throat (26%). Median threshold delay between admission and symptoms onset adopted for HAI definition was 48 hour (range: 24‐96 hour).

Conclusion

This work underlined the heterogeneity of HAI definitions in different countries. A standardized definition would be helpful to evaluate HAI spread, outcomes in patients and healthcare systems, and the impact of prevention measures, including vaccination.

A clinical approach to the threat of emerging influenza viruses in the Asia-Pacific region

Seasonal influenza epidemics and periodic pandemics are important causes of morbidity and mortality. Patients with chronic co‐morbid illness, those at the extremes of age and pregnant women are at higher risks of complications requiring hospitalization, whereas young adults and obese individuals were also at increased risk during the A(H1N1) pandemic in 2009. Avian influenza A(H5N1) and A(H7N9) viruses have continued to circulate widely in some poultry populations and infect humans sporadically since 1997 and 2013, respectively. The recent upsurge in human cases of A(H7N9) infections in Mainland China is of great concern. Sporadic human cases of avian A(H5N6), A(H10N8) and A(H6N1) have also emerged in recent years while there are also widespread poultry outbreaks due to A(H5N8) in many countries. Observational studies have shown that treatment with a neuraminidase inhibitor (NAI) for adults hospitalized with severe influenza is associated with lower mortality and better clinical outcomes, especially when administered early in the course of illness. Whether higher than standard doses of NAI would provide greater antiviral effects in such patients will require further investigation. High‐dose systemic corticosteroids were associated with worse outcomes in patients with severe influenza. There is an urgent need for developing more effective antiviral therapies for treatment of influenza infections.

Influenza Vaccination of Healthcare Workers: Critical Analysis of the Evidence for Patient Benefit Underpinning Policies of Enforcement

BACKGROUND

Four cluster randomized controlled trials (cRCTs) conducted in long-term care facilities (LTCFs) have reported reductions in patient risk through increased healthcare worker (HCW) influenza vaccination. This evidence has led to expansive policies of enforcement that include all staff of acute care hospitals and other healthcare settings beyond LTCFs. We critique and quantify the cRCT evidence for indirect patient benefit underpinning policies of mandatory HCW influenza vaccination.

METHODS

Plausibility of the four cRCT findings attributing indirect patient benefits to HCW influenza vaccination was assessed by comparing percentage reductions in patient risk reported by the cRCTs to predicted values. Plausibly predicted values were derived according to the basic mathematical principle of dilution, taking into account HCW influenza vaccine coverage and the specificity of patient outcomes for influenza. Accordingly, predicted values were calculated as a function of relevant compound probabilities including vaccine efficacy (ranging 40-60% in HCWs and favourably assuming the same indirect protection conferred through them to patients) × change in proportionate HCW influenza vaccine coverage (as reported by each cRCT) × percentage of a given patient outcome (e.g. influenza-like illness (ILI) or all-cause mortality) plausibly due to influenza virus. The number needed to vaccinate (NNV) for HCWs to indirectly prevent patient death was recalibrated based on real patient data of hospital-acquired influenza, with adjustment for potential under-detection (5.2-fold), and using favourable assumptions of HCW-attributable risk (ranging 60-80%).

RESULTS

In attributing patient benefit to increased HCW influenza vaccine coverage, each cRCT was found to violate the basic mathematical principle of dilution by reporting greater percentage reductions with less influenza-specific patient outcomes (i.e., all-cause mortality > ILI > laboratory-confirmed influenza) and/or patient mortality reductions exceeding even favourably-derived predicted values by at least 6- to 15-fold. If extrapolated to all LTCF and hospital staff in the United States, the prior cRCT-claimed NNV of 8 would implausibly mean >200,000 and >675,000 patient deaths, respectively, could be prevented annually by HCW influenza vaccination, inconceivably exceeding total US population mortality estimates due to seasonal influenza each year, or during the 1918 pandemic, respectively. More realistic recalibration based on actual patient data instead shows that at least 6000 to 32,000 hospital workers would need to be vaccinated before a single patient death could potentially be averted.

CONCLUSIONS

The four cRCTs underpinning policies of enforced HCW influenza vaccination attribute implausibly large reductions in patient risk to HCW vaccination, casting serious doubts on their validity. The impression that unvaccinated HCWs place their patients at great influenza peril is exaggerated. Instead, the HCW-attributable risk and vaccine-preventable fraction both remain unknown and the NNV to achieve patient benefit still requires better understanding. Although current scientific data are inadequate to support the ethical implementation of enforced HCW influenza vaccination, they do not refute approaches to support voluntary vaccination or other more broadly protective practices, such as staying home or masking when acutely ill.

Lower Respiratory Tract Infections

This review will focus on the infectious etiologies and more common noninfectious causes of lower respiratory tract syndromes among major immunosuppressed populations. The changing epidemiology of infections in the era of highly active antiretroviral therapy (HAART) in the case of HIV-positive patients and the impacts of both newer immune-suppressant therapies and anti-infective prophylaxis for other immunocompromised hosts will be discussed, with emphasis on diagnostic approaches and practice algorithms.

Association of increased influenza vaccination in health care workers with a reduction in nosocomial influenza infections in cancer patients

BACKGROUND

Vaccination of health care workers (HCWs) remains a key strategy to reduce the burden of influenza infections in cancer patients.

METHODS

In this 8-year study, we evaluated the effect of a multifaceted approach, including a mandatory influenza vaccination program, on HCW vaccination rates and its effect on nosocomial influenza infections in cancer patients.

RESULTS

The influenza vaccination rate of all employees significantly increased from 56% (8,762/15,693) in 2006-2007 to 94% (17,927/19,114) in 2013-2014 (P < .0001). The 2009 mandatory participation program increased HCW vaccination rates in the targeted groups (P < .0001), and the addition of an institutional policy in 2012 requiring influenza vaccination or surgical mask use with each patient contact further increased vaccination rates by 10%-18% for all groups in 1 year. The proportion of nosocomial influenza infections significantly decreased (P = .045) during the study period and was significantly associated with increased HCW vaccination rates in the nursing staff (P = .043) and in personnel working in high-risk areas (P = .0497).

CONCLUSIONS

Multifaceted influenza vaccination programs supported by institutional policy effectively increased HCW vaccination rates. Increased HCW vaccination rates were associated with a reduction in the proportion of nosocomial influenza infections in immunocompromised cancer patients.

Increasing the coverage of influenza vaccination in healthcare workers: review of challenges and solutions

Seasonal influenza vaccine uptake rate of healthcare workers (HCWs) varies widely from <5% to >90% worldwide. Perception of vaccine efficacy and side-effects are conventional factors affecting the uptake rates. These factors may operate on a personal and social level, impacting the attitudes and behaviours of HCWs. Vaccination rates were also under the influence of the occurrence of other non-seasonal influenza pandemics such as avian influenza. Different strategies have been implemented to improve vaccine uptake, with important ones including the enforcement of the local authority's recommendations, promulgation of practice guidelines, and mandatory vaccination polices. Practised in some regions in North America, mandatory policies have led to higher vaccination rate, but are not problem-free. The effects of conventional educational programmes and campaigns are in general of modest impact only. Availability of convenient vaccination facilities, such as mobile vaccination cart, and role models of senior HCWs receiving vaccination are among some strategies which have been observed to improve vaccination uptake rate. A multi-faceted approach is thus necessary to persuade HCWs to participate in a vaccination programme, especially in areas with low uptake rate.

Characteristics and management of patients with influenza in a German hospital during the 2014/2015 influenza season

The objective of this study was to review the management of patients with influenza during the influenza season 2014/2015 (n = 197). Our study revealed a high rate of healthcare-associated influenza infection (35.5 %) and a correlation between the total number of patients with HA influenza and the number of nurses on sick leave. The results of the study underline the importance of strict hygiene management. Furthermore, widespread influenza vaccination for both high-risk patients and health care workers is recommended.

Do we have enough evidence how seasonal influenza is transmitted and can be prevented in hospitals to implement a comprehensive policy?

•

Vaccinated HCW 4.81, unvaccinated 7.54 lab-proven influenza episodes/100 HCWs/ season.

•

2 RCTs partly directly-observed HCW mask wearing, 4 not observed underpowered, no effect on influenza transmission.

•

There are no RCTs of screening HCWs/patients for influenza before entering hospital to prevent transmission.

•

H₂O₂ vapor systems effectively clean patient rooms/medical equipment of influenza

Purpose

To identify if there is enough evidence at low risk-of-bias to prevent influenza transmission by vaccinating health-care workers (HCWs), patients and visitors; screening for laboratory-proven influenza all entering hospitals; screening asymptomatic individuals; identifying influenza supershedders; hand-washing and mask-wearing by HCWs, patients and visitors; and cleaning hospital rooms and equipment.

Principal Results

Vaccination reduces influenza episodes of vaccinated (4.81/100 HCW) compared to unvaccinated (7.54/100) HCWs/influenza season. A Cochrane review found for inactivated vaccines the Number Needed to Vaccinate (NNV) = 71 (95%CI 64%, 80%) for adults 18–60 (same age as HCWs) to prevent laboratory-proven influenza. There are no RCTs of screening HCWs, patients, visitors and influenza supershedders to prevent transmission. None of four RCTs of HCWs mask-wearing (two directly observed, two not) showed an effect because they were underpowered either due to small size or low circulation of influenza. Hospital rooms and equipment can effectively be cleaned of influenza by many chemicals and hydrogen peroxide vapor machines but the cleaning cycle needs shortening to increase the likelihood of adoption.

Major Conclusions

HCW vaccination is a partial solution with current vaccination levels. There are no RCTs of screening HCWs, patients and visitors demonstrating preventing influenza transmission. Only one study costed furloughing HCWs with influenza and no RCTs have identified benefits of isolating influenza supershedders. RCTs of directly- and electronically continuously-observed mask-wearing and hand-hygiene and RCTs of incentives for meticulous hygiene are required. RCTs of engineering solutions (external venting, frequent room air changes) are needed. A wide range of chemicals effectively cleans hospital rooms and equipment from influenza. Hydrogen peroxide vapor is effective against influenza and a wide range of bacterial pathogens with patient room changes, and clean areas cleaners do not clean but its cleaning cycle needs shortening to increase the likelihood of adoption of cleaning rooms vacated by influenza patients.

Diagnosis and features of hospital-acquired pneumonia: a retrospective cohort study

Background

Hospital-acquired pneumonia (HAP) is defined as radiologically confirmed pneumonia occurring ≥48 h after hospitalization, in non-intubated patients. Empirical treatment regimens use broad-spectrum antimicrobials.

Aim

To evaluate the accuracy of the diagnosis of HAP and to describe the demographic and microbiological features of patients with HAP.

Methods

Medical and surgical inpatients receiving intravenous antimicrobials for a clinical diagnosis of HAP at a UK tertiary care hospital between April 2013 and 2014 were identified. Demographic and clinical details were recorded.

Findings

A total of 166 adult patients with a clinical diagnosis of HAP were identified. Broad-spectrum antimicrobials were prescribed, primarily piperacillin–tazobactam (57.2%) and co-amoxiclav (12.5%). Sputum from 24.7% of patients was obtained for culture. Sixty-five percent of patients had radiological evidence of new/progressive infiltrate at the time of HAP treatment, therefore meeting HAP diagnostic criteria (2005 American Thoracic Society/Infectious Diseases Society of America guidelines). Radiologically confirmed HAP was associated with higher levels of inflammatory markers and sputum culture positivity. Previous surgery and/or endotracheal intubation were associated with radiologically confirmed HAP. A bacterial pathogen was identified from 17/35 sputum samples from radiologically confirmed HAP patients. These were Gram-negative bacilli (N = 11) or Staphylococcus aureus (N = 6). Gram-negative bacteria tended to be resistant to co-amoxiclav, but susceptible to ciprofloxacin, piperacillin–tazobactam and meropenem. Five of the six S. aureus isolates were meticillin susceptible and all were susceptible to doxycycline.

Conclusion

In ward-level hospital practice ‘HAP’ is an over-used diagnosis that may be inaccurate in 35% of cases when objective radiological criteria are applied. Radiologically confirmed HAP represents a distinct clinical and microbiological phenotype. Potential risk factors were identified that could represent targets for preventive interventions.

Characterisation of nosocomial and community-acquired influenza in a large university hospital during two consecutive influenza seasons

BACKGROUND

Nosocomial influenza is increasingly recognized as an important public health threat causing considerable morbidity and mortality each year. However, data on nosocomial influenza is usually collected during outbreaks only and clinical information of nosocomial influenza is sparsely available.

OBJECTIVES

To systematically analyse the distribution of nosocomial and community-acquired influenza and epidemiological characteristics in a tertiary care unit in two consecutive seasons.

STUDY DESIGN

A retrospective observational study was conducted to identify and characterise cases of nosocomial and community-acquired influenza at Freiburg University hospital from 1 January 2013 to 30 April 2014. A validated multiplex RT-PCR to detect influenza virus and other respiratory pathogens was used throughout. Clinical information was retrieved from the hospital-based information system.

RESULTS

Overall, 218 patients with laboratory-confirmed influenza were included (179 in the first, 39 patients in the second season). A rate of 20% of nosocomial influenza was observed throughout. A fatal outcome was recorded for 9% of nosocomial cases, which were mainly associated with influenza virus A(H1N1)pdm09. Nosocomial influenza occurred in all age groups, but fatalities were only observed in patients ≥18 years. Patients with nosocomial influenza were significantly older, underwent therapy for blood malignancies and immunosuppressive regimens more frequently, and received solid organ transplantation more often compared to community-acquired patients.

CONCLUSIONS

Despite the different distribution of virus subtypes and epidemiological properties between both influenza seasons, the rate of nosocomial cases remained similar. Systematic detection and targeted prevention measures seem mandatory to minimize nosocomial influenza.

Influenza Immunization for All Health Care Personnel: Keep It Mandatory

The purpose of this statement is to reaffirm the American Academy of Pediatrics' support for a mandatory influenza immunization policy for all health care personnel. With an increasing number of organizations requiring influenza vaccination, coverage among health care personnel has risen to 75% in the 2013 to 2014 influenza season but still remains below the Healthy People 2020 objective of 90%. Mandatory influenza immunization for all health care personnel is ethical, just, and necessary to improve patient safety. It is a crucial step in efforts to reduce health care-associated influenza infections.

Epidemiological features of influenza in Canadian adult intensive care unit patients

To identify predictive factors and mortality of patients with influenza admitted to intensive care units (ICU) we carried out a prospective cohort study of patients hospitalized with laboratory-confirmed influenza in adult ICUs in a network of Canadian hospitals between 2006 and 2012. There were 626 influenza-positive patients admitted to ICUs over the six influenza seasons, representing 17·9% of hospitalized influenza patients, 3·1/10,000 hospital admissions. Variability occurred in admission rate and proportion of hospital influenza patients who were admitted to ICUs (proportion range by year: 11·7-29·4%; 21·3% in the 2009-2010 pandemic). In logistic regression models ICU patients were younger during the pandemic and post-pandemic period, and more likely to be obese than hospital non-ICU patients. Influenza B accounted for 14·2% of all ICU cases and had a similar ICU admission rate as influenza A. Influenza-related mortality was 17·8% in ICU patients compared to 2·0% in non-ICU patients.