Effect of two-step hygiene management on the prevention of nosocomial influenza in a season with high influenza activity

Focusing on severe infections with the respiratory syncytial virus (RSV) in adults: Risk factors, symptomatology and clinical course compared to influenza A / B and the original SARS-CoV-2 strain

BACKGROUND

The role and impact of RSV in the adult population is not well understood and comparative data of RSV infection, influenza A/B and SARS-CoV-2 in the elderly hospitalized for respiratory infections is limited.

METHODS

In a retrospective, monocentric study we analyzed data of adult patients with respiratory infections tested positive by PCR for RSV, Influenza A/B and SARS-CoV-2 over a four-year period from 2017 to 2020. Symptoms on admission, laboratory results, and risk factors were assessed, and the clinical course and outcomes were studied.

RESULTS

A total of 1541 patients hospitalized with respiratory disease and PCR positive for one of the 4 viruses were enrolled in the study. RSV was the second most prevalent virus before the COVID-19 pandemic and RSV patients represent the oldest group in this study with an average age of 75 years. Neither clinical nor laboratory characteristics differ clearly between RSV, Influenza A / B and SARS-CoV-2 infections. Up to 85% of patients had risk factors, with COPD and kidney disease found particularly frequently in RSV infections. Hospital stay was 12.66 days for RSV patients and thus significantly longer than for influenza A / B (10.88 and 8.86, respectively, p < 0.001), but shorter than for SARS-CoV-2 (17.87 days, p < 0.001). The risk for ICU admission and the rate of mechanical ventilation were also higher for RSV than for influenza A (OR 1.69 (p = 0.020) and 1.59 (p = 0.050)) and influenza B: (1.98 (p = 0.018) and 2.33 (p < 0.001)), but lower than for SARS-CoV-2 (0.65 (p < 0.001) and 0.59 (p = 0.035)). The risk of hospital mortality for RSV was increased compared with influenza A (1.55 (p = 0.050)) and influenza B (1.42 (p = 0.262)), but lower compared to SARs-CoV-2 (0.37 (p < 0.001).

CONCLUSION

RSV infections in elderly are frequent and more severe than those with influenza A/B. While the impact of SARS-CoV-2 most likely decreased in the elderly population due to vaccination, RSV can be expected to continue to be problematic for elderly patients, especially those with comorbidities and thus, more awareness on the disastrous impact of RSV in this age group is urgently needed.

SARS-CoV-2-Infection (COVID-19): Clinical Course, Viral Acute Respiratory Distress Syndrome (ARDS) and Cause(s) of Death

SARS-CoV-2-infected symptomatic patients often suffer from high fever and loss of appetite which are responsible for the deficit of fluids and of protein intake. Many patients admitted to the emergency room are, therefore, hypovolemic and hypoproteinemic and often suffer from respiratory distress accompanied by ground glass opacities in the CT scan of the lungs. Ischemic damage in the lung capillaries is responsible for the microscopic hallmark, diffuse alveolar damage (DAD) characterized by hyaline membrane formation, fluid invasion of the alveoli, and progressive arrest of blood flow in the pulmonary vessels. The consequences are progressive congestion, increase in lung weight, and progressive hypoxia (progressive severity of ARDS). Sequestration of blood in the lungs worsens hypovolemia and ischemia in different organs. This is most probably responsible for the recruitment of inflammatory cells into the ischemic peripheral tissues, the release of acute-phase mediators, and for the persistence of elevated serum levels of positive acute-phase markers and of hypoalbuminemia. Autopsy studies have been performed mostly in patients who died in the ICU after SARS-CoV-2 infection because of progressive acute respiratory distress syndrome (ARDS). In the death certification charts, after respiratory insufficiency, hypovolemic heart failure should be mentioned as the main cause of death.

Current Opinion in LAIV: A Matter of Parent Virus Choice

Influenza is still a frequent seasonal infection of the upper respiratory tract, which may have deadly consequences, especially for the elderly. This is in spite of the availability of vaccines suggested for persons above 65 years of age. Two types of conventional influenza vaccines are currently licensed for use-live attenuated and inactivated vaccines. Depending on local regulatory requirements, live attenuated vaccines are produced by the reverse genetics technique or by classical reassortment in embryonated chicken eggs. Sometimes, the efficiency of classical reassortment is complicated by certain properties of the wild-type parent virus. Cases of low efficacy of vaccines have been noted, which, among other reasons, may be associated with suboptimal properties of the wild-type parent virus that are not considered when recommendations for influenza vaccine composition are made. Unfortunately, knowledge surrounding the roles of properties of the circulating influenza virus and its impact on the efficacy of the reassortment process, vaccination efficiency, the infectivity of the vaccine candidates, etc., is now scattered in different publications. This review summarizes the main features of the influenza virus that may dramatically affect different aspects of the preparation of egg-derived live attenuated vaccine candidates and their effectiveness. The author expresses her personal view, which may not coincide with the opinion of other experts in the field of influenza vaccines.

Effect of a multimodal strategy for prevention of nosocomial influenza: a retrospective study at Grenoble Alpes University Hospital from 2014 to 2019

Background

A multimodal strategy to prevent nosocomial influenza was implemented in 2015–2016 in Grenoble Alpes University Hospital. Three modalities were implemented in all units: promotion of vaccination among healthcare workers, epidemiologic surveillance and communication campaigns. Units receiving a high number of patients with influenza implemented 2 additional modalities: improvement of diagnosis capacities and systematic surgical mask use. The main objective was to assess the effectiveness of the strategy for reducing the risk of nosocomial influenza.

Methods

A study was conducted retrospectively investigating 5 epidemic seasons (2014–2015 to 2018–2019) including all patients hospitalized with a positive influenza test at Grenoble Alpes University Hospital. The weekly number of nosocomial influenza cases was analyzed by Poisson regression and incidence rate ratios (IRR) were estimated.

Results

A total of 1540 patients, resulting in 1559 stays, were included. There was no significant difference between the 5 influenza epidemic seasons in the units implementing only 3 measures. In the units implementing the 5 measures, there was a reduction of nosocomial influenza over the seasons when the strategy was implemented compared to the 2014–2015 epidemic season (IRR = 0.56, 95% CI = 0.23–1.34 in 2015–2016; IRR = 0.39, 95% CI = 0.19–0.81 in 2016–2017; IRR = 0.50, 95% CI = 0.24–1.03 in 2017–2018; IRR = 0.48, 95% CI = 0.23–0.97 in 2018–2019).

Conclusions

Our data mainly suggested that the application of the strategy with 5 modalities, including systematic surgical mask use and rapid diagnosis, seemed to reduce by half the risk of nosocomial influenza. Further data, including medico-economic studies, are necessary to determine the opportunity of extending these measures at a larger scale.

New Insights into the Prevention of Hospital-Acquired Pneumonia/Ventilator-Associated Pneumonia Caused by Viruses

A fifth or more of hospital-acquired pneumonias may be attributable to respiratory viruses. The SARS-CoV-2 pandemic has clearly demonstrated the potential morbidity and mortality of respiratory viruses and the constant threat of nosocomial transmission and hospital-based clusters. Data from before the pandemic suggest the same can be true of influenza, respiratory syncytial virus, and other respiratory viruses. The pandemic has also helped clarify the primary mechanisms and risk factors for viral transmission. Respiratory viruses are primarily transmitted by respiratory aerosols that are routinely emitted when people exhale, talk, and cough. Labored breathing and coughing increase aerosol generation to a much greater extent than intubation, extubation, positive pressure ventilation, and other so-called aerosol-generating procedures. Transmission risk is proportional to the amount of viral exposure. Most transmissions take place over short distances because respiratory emissions are densest immediately adjacent to the source but then rapidly dilute and diffuse with distance leading to less viral exposure. The primary risk factors for transmission then are high viral loads, proximity, sustained exposure, and poor ventilation as these all increase net viral exposure. Poor ventilation increases the risk of long-distance transmission by allowing aerosol-borne viruses to accumulate over time leading to higher levels of exposure throughout an enclosed space. Surgical and procedural masks reduce viral exposure but do not eradicate it and thus lower but do not eliminate transmission risk. Most hospital-based clusters have been attributed to delayed diagnoses, transmission between roommates, and staff-to-patient infections. Strategies to prevent nosocomial respiratory viral infections include testing all patients upon admission, preventing healthcare providers from working while sick, assuring adequate ventilation, universal masking, and vaccinating both patients and healthcare workers.

Management of hospitalized influenza A patients during the season 2018/19 : Comparison of three medical departments and the effect on outcome and antibiotic usage

BACKGROUND

Diagnosis and treatment of influenza patients are often provided across several medical specialties. We compared patient outcomes at an infectious diseases (ID), a rheumatology (Rheu) and a pulmonology (Pul) department.

MATERIAL AND METHODS

In this prospective observational multicenter study we included all influenza positive adults who were hospitalized and treated at flu isolation wards in three hospitals in Vienna during the season 2018/2019.

RESULTS

A total of 490 patients (49% female) with a median age of 73 years (interquartile range [IQR] 61-82) were included. No differences regarding age, sex and most underlying diseases were present at admission. Frequencies of the most common complications differed: acute kidney failure (ID 12.7%, Rheu 21.2%, Pulm 37.1%, p < 0.001), acute heart failure (ID 4.3%, Rheu 17.1%, Pulm 14.4%, p < 0.001) and respiratory insufficiency (ID 45.1%, Rheu 41.5%, Pulm 56.3%, p = 0.030). Oseltamivir prescription was lowest at the pulmonology flu ward (ID 79.6%, Rheu 90.5%, Pulm 61.7%, p < 0.001). In total 176 patients (35.9%) developed pneumonia. Antibiotic selection varied between the departments: amoxicillin/clavulanic acid (ID 28.9%, Rheu 63.8%, Pulm 5.9%, p < 0.001), cefuroxime (ID 28.9%, Rheu 1.3%, Pulm 0%, p < 0.001), 3rd generation cephalosporins (ID 4.4%, Rheu 5%, Pulm 72.5%, p < 0.001), doxycycline (ID 17.8%, Rheu 0%, Pulm 0%, p < 0.001). The median length of stay was significantly different between wards: ID 6 days (IQR 5-8), Rheu 6 days (IQR 5-7) and Pulm 7 days (IQR 5-9.5, p = 0.034). In-hospital mortality was 4.3% and did not differ between specialties.

CONCLUSION

We detected differences in oseltamivir usage, length of in-hospital stay and antibiotic choices for pneumonia. Influenza-associated mortality was unaffected by specialty.

Effect of a strict hygiene bundle for the prevention of nosocomial transmission of SARS-CoV-2 in the hospital: a practical approach from the field

Background

During the novel coronavirus disease (COVID-19) pandemic it is crucial for hospitals to implement infection prevention strategies to reduce nosocomial transmission to the lowest possible number. This is all the more important because molecular tests for identifying SARS-CoV-2 infected patients are uncertain, and the resources available for them are limited. In this view, a monocentric, retrospective study with an interventional character was conducted to investigate the extent to which the introduction of a strict hygiene bundle including a general mask requirement and daily screening for suspicious patients has an impact on the SARS-CoV-2 nosocomial rate in the pandemic environment.

Methods

All inpatients from a maximum care hospital in Regensburg (Bavaria) between March 1st and June 10th 2020 were included. Patient with respiratory symptoms were tested for SARS-CoV-2 at admission, patients were managed according to a standard hygiene protocol. At the end of March a strict hygiene bundle was introduced including a general mask obligation and a daily clinical screening of inpatients for respiratory symptoms. Nosocomial infection rate for COVID-19 and the risk for infection transmission estimated by the nosocomial incidence density before and after introduction the hygiene bundle were compared. The infection pressure for the hospital during the entire observational period was characterized by the infection reports in the region in relation to the number of hospitalized COVID-19 patients and the number of infected employees.

Results

In fact, after the introduction of a strict hygiene bundle including a general mouth and nose protection obligation and a daily clinical screening of suspicious patients, a significant reduction of the nosocomial rate from 0.28 to 0.06 (p = 0.026) was observed. Furthermore, the risk of spreading hospital-acquired infections also decreased dramatically from 0.0007 to 0.00018 (p = 0.031; rate ratio after/before 0.25 (95%CI 0.06, 1.07) despite a slow decrease of the hospital COVID 19-prevalence and an increase of infected employees.

Conclusion

The available data underline that a strict hygiene bundle seem to be associated with a decrease of nosocomial SARS-CoV-2 transmission in the pandemic situation.

Incidence and characteristics of nosocomial influenza in a country with low vaccine coverage

BACKGROUND

Influenza vaccination coverage is low in France, in at-risk patients and in healthcare workers.

AIM

We aimed to estimate the incidence of nosocomial influenza, its characteristics and outcome.

METHODS

During one influenza season, we retrospectively evaluated all cases of documented influenza. Inpatients with symptoms onset ≥48 h after admission were enrolled. Data were collected on a standardized questionnaire.

RESULTS

From November 2017 to April 2018, 860 patients tested positive for influenza by polymerase chain reaction analysis on a respiratory sample. Among them, 204 (23.7%) were diagnosed ≥48 h after admission, of whom 57 (6.6% of all influenza cases) fulfilled inclusion criteria for nosocomial influenza: 26 women and 31 men, median age 82 years (interquartile range, 72.2-86.9). Twenty patients (38.6%) had recently (<6 months) received the seasonal influenza vaccine. Median time between admission and symptoms onset, and between symptoms onset and diagnosis were, respectively, 11 days (7-19.5) and 29 h (15.5-48). Influenza was mostly acquired in a double-bedded room (N = 39, 68.4%), with documented exposure in 14 cases. Influenza B virus was more common in nosocomial (46/57, 80.7%), than in community-acquired cases (359/803, 44.6%), P<0.001. Mortality rate at three months was 15.8% (N = 9). Incidence of nosocomial influenza was estimated at 0.22 per 1000 hospital-days during the study period.

CONCLUSION

Nosocomial influenza is not rare in elderly inpatients, and may have severe consequences. Influenza B virus was over-represented, which suggests higher transmissibility and/or transmission clusters.

Effectiveness of N95 respirators versus surgical masks against influenza: A systematic review and meta-analysis

OBJECTIVE

Previous meta-analyses concluded that there was insufficient evidence to determine the effect of N95 respirators. We aimed to assess the effectiveness of N95 respirators versus surgical masks for prevention of influenza by collecting randomized controlled trials (RCTs).

METHODS

We searched PubMed, EMbase and The Cochrane Library from the inception to January 27, 2020 to identify relevant systematic reviews. The RCTs included in systematic reviews were identified. Then we searched the latest published RCTs from the above three databases and searched ClinicalTrials.gov for unpublished RCTs. Two reviewers independently extracted the data and assessed risk of bias. Meta-analyses were conducted to calculate pooled estimates by using RevMan 5.3 software.

RESULTS

A total of six RCTs involving 9 171 participants were included. There were no statistically significant differences in preventing laboratory-confirmed influenza (RR = 1.09, 95% CI 0.92-1.28, P > .05), laboratory-confirmed respiratory viral infections (RR = 0.89, 95% CI 0.70-1.11), laboratory-confirmed respiratory infection (RR = 0.74, 95% CI 0.42-1.29) and influenzalike illness (RR = 0.61, 95% CI 0.33-1.14) using N95 respirators and surgical masks. Meta-analysis indicated a protective effect of N95 respirators against laboratory-confirmed bacterial colonization (RR = 0.58, 95% CI 0.43-0.78).

CONCLUSION

The use of N95 respirators compared with surgical masks is not associated with a lower risk of laboratory-confirmed influenza. It suggests that N95 respirators should not be recommended for general public and nonhigh-risk medical staff those are not in close contact with influenza patients or suspected patients.

Dynamics of Drug Resistance: Optimal Control of an Infectious Disease

Antimicrobial resistance is a significant public health threat. In the U.S. alone, 2 million people are infected and 23,000 die each year from antibiotic resistant bacterial infections. In many cases, infections are resistant to all but a few remaining drugs. We examine the case where a single drug remains and solve for the optimal treatment policy for an SIS infectious disease model incorporating the effects of drug resistance. The problem is formulated as an optimal control problem with two continuous state variables, the disease prevalence and drug's "quality" (the fraction of infections that are drug-susceptible). The decision maker's objective is to minimize the discounted cost of the disease to society over an infinite horizon. We provide a new generalizable solution approach that allows us to thoroughly characterize the optimal treatment policy analytically. We prove that the optimal treatment policy is a bang-bang policy with a single switching time. The action/inaction regions can be described by a single boundary that is strictly increasing when viewed as a function of drug quality, indicating that when the disease transmission rate is constant, the policy of withholding treatment to preserve the drug for a potentially more serious future outbreak is not optimal. We show that the optimal value function and/or its derivatives are neither C ¹ nor Lipschitz continuous suggesting that numerical approaches to this family of dynamic infectious disease models may not be computationally stable. Furthermore, we demonstrate that relaxing the standard assumption of constant disease transmission rate can fundamentally change the shape of the action region, add a singular arc to the optimal control, and make preserving the drug for a serious outbreak optimal. In addition, we apply our framework to the case of antibiotic resistant gonorrhea.

Influenza and respiratory syncytial virus screening for the detection of asymptomatically infected patients in hematology and oncology

Introduction: Respiratory syncytial virus (RSV) and influenza virus infections are a significant healthcare risk for immunocompromised patients. In addition to community onset, nosocomial acquisition and transmission may also occur. Detection of asymptomatic shedders (e.g., patients in the incubation period or immunosuppressed long term shedders) facilitates control of nosocomial transmission.

Methods: To strengthen the existing infection control concept, a PCR-based screening for RSV and influenza virus was implemented for all patients lacking respiratory symptoms (asymptomatic patients) who were hospitalized on an adult and a pediatric hemato-oncological ward. Laboratory results of this screening were analyzed retrospectively.

Results: 665 respiratory specimens were obtained for screening from 251 patients (26% were 18 years and younger) from December 2016 to April 2017. In 23 patients without respiratory symptoms, either influenza virus or RSV infection was found, resulting in a detection rate of about 9%. In 6 patients, the infection was presumably detected during the incubation period, because an increase of viral load was observed in subsequent specimens. Positive screening results facilitated timely implementation of adequate infection control precautions. Nosocomial clusters of RSV or influenza were not detected during the screening period on the two wards.

Conclusion: The seasonal screening program expanded our existing infection control concept in terms of patients lacking respiratory symptoms who shed influenza virus or RSV. It enabled us to identify 23 RSV or influenza infections in patients lacking respiratory symptoms in a 4-month period and thus to rapidly take isolation precautions.

Clinical efficacy of seasonal influenza vaccination: characteristics of two outbreaks of influenza A(H1N1) in immunocompromised patients

BACKGROUND

Influenza A(H1N1) causes serious complications in immunocompromised patients. The efficacy of seasonal vaccination in these patients has been questioned.

AIM

To describe two outbreaks of influenza A(H1N1) in immunocompromised patients.

METHODS

Two outbreaks of influenza A(H1N1) occurred in our institution: on the kidney transplant ward in 2014 including patients early after kidney or simultaneous pancreas-kidney transplantation, and on the oncology ward in 2016 including patients receiving chemotherapy for malignant tumours. Factors leading to these outbreaks and the clinical efficacy of seasonal influenza vaccination were analysed.

FINDINGS

Altogether 86 patients were exposed to influenza A(H1N1) during the outbreaks, among whom the seasonal influenza vaccination status was unknown in 10. Only three out of 38 vaccinated patients were infected with influenza A(H1N1), compared with 20 out of 38 unvaccinated patients (P = 0.02). The death of one out of 38 vaccinated patients was associated with influenza, compared with seven out of 38 unvaccinated patients (P = 0.06). Shared factors behind the two outbreaks included outdated facilities not designed for the treatment of immunosuppressed patients. Vaccination coverage among patients was low, between 40% and 70% despite vaccination being offered to all patients free of charge. Vaccination coverage of healthcare workers on the transplant ward was low (46%), but, despite high coverage on the oncology ward (92%), the outbreak occurred.

CONCLUSION

Seasonal influenza vaccination was clinically effective with both a reduced risk of influenza infection and a trend towards reduced mortality in these immunocompromised patients. Several possible causes were identified behind these two outbreaks, requiring continuous awareness in healthcare professionals to prevent further outbreaks.