Timing of oseltamivir administration and outcomes in hospitalized adults with pandemic 2009 influenza A(H1N1) virus infection

Effectivity of Repurposed Drugs Against SARS-CoV-2 Infections, A Hope for COVID 19: Inhibitor Modelling studies by Docking and Molecular Dynamics

In the present study, we have done a comparative study on the efficacy of some currently used repurposed drugs: Oseltamivir (O), Favipiravir (F) and Hydroxychloroquine (H) in individual and in their combinational mode against CoV-2 infections. The ADME analysis has helped us to identify the inhibitory possibility of the tested drugs towards receptor 3CL^pro protein of SARS-CoV-2. Various thermodynamical parameters obtained from Molecular Docking, Molecular dynamics (MD) and MMPBSA simulations like binding affinity, potential energy (E_pot), RMSD, RMSF, SASA energy, interaction energies, Gibbs free energy (ΔG_bind) etc. also helped us to verify the effectivity of mentioned drugs against CoV-2 protease.

Flu@home: The comparative accuracy of an at-home influenza rapid diagnostic test, using a pre-positioned test kit, mobile app, mail-in reference sample, and symptom-based testing trigger

At-home testing with rapid diagnostic tests (RDTs) for respiratory viruses could facilitate early diagnosis, guide patient care, and prevent transmission. Such RDTs are best used near the onset of illness when viral load is highest and clinical action will be most impactful, which may be achieved by at-home testing. We evaluated the diagnostic accuracy of the QuickVue Influenza A + B RDT in an at-home setting. A convenience sample of 5,229 individuals who were engaged with an on-line health research platform were prospectively recruited throughout the United States. "flu@home" test kits containing a QuickVue RDT and reference sample collection and shipping materials were pre-positioned with participants at the beginning of the study. Participants responded to daily symptom surveys. If they reported experiencing cough along with aches, fever, chills, and/or sweats, they used their flu@home kit following instructions on a mobile app and indicated what lines they saw on the RDT. Of the 976 participants who met criteria to use their self-collection kit and completed study procedures, 202 (20.7%) were positive for influenza by qPCR. The RDT had a sensitivity of 28% (95% CI: 21-36) and specificity of 99% (98-99) for influenza A, and 32% (95% CI: 20-46) and 99% (95% CI: 98-99), for influenza B. Our results support the concept of app-supported, pre-positioned at-home RDT kits using symptom-based triggers, although it cannot be recommended with the RDT used in this study. Further research is needed to determine ways to improve the accuracy and utility of home-based testing for influenza.

SARS-CoV-2 Antiviral Therapy

The development of effective antiviral therapy for COVID-19 is critical for those awaiting vaccination, as well as for those who do not respond robustly to vaccination. This review summarizes 1 year of progress in the race to develop antiviral therapies for COVID-19, including research spanning preclinical and clinical drug development efforts, with an emphasis on antiviral compounds that are in clinical development or that are high priorities for clinical development. The review is divided into sections on compounds that inhibit SARS-CoV-2 enzymes, including its polymerase and proteases; compounds that inhibit virus entry, including monoclonal antibodies; interferons; and repurposed drugs that inhibit host processes required for SARS-CoV-2 replication. The review concludes with a summary of the lessons to be learned from SARS-CoV-2 drug development efforts and the challenges to continued progress.

The Impact of Immunization and Use of Oseltamivir on Influenza-Related Hospitalizations: A Population-Based Study

Background

As the COVID-19 pandemic continues into flu season, it is critical to minimize hospitalizations to maximize capacity and preserve critical care resources. We sought to identify risk factors for influenza-related hospitalization, specifically the role of immunization and oseltamivir prescriptions.

Methods

Patients with influenza diagnoses were identified from the MarketScan database (2014-2018). Primary risk factors of interest were an influenza vaccination within 6 months prior to infection and oseltamivir prescriptions (filled on the day diagnosis, the following day, or 2-5 days). A multivariable logistic regression model was run to identify risk factors for influenza-related hospitalizations within 30 days of diagnosis.

Results

Among 2 395 498 influenza infections, 0.27% were hospitalized. Of those prescribed oseltamivir the day of diagnosis, 0.13% were later hospitalized, compared to 0.67% among those who filled prescriptions the following day and 11.8% when filled within 2 to 5 days. Upon adjustment, oseltamivir prescriptions filled on the day of diagnosis were associated with significantly decreased odds of hospitalization (OR 0.51 CI 0.48-0.55). Prescriptions filled within 1 to 5 days of diagnosis were associated with significantly increased odds of hospitalization (1 day OR 2.01 CI 1.81-2.24; 2-5 days OR 34.1 CI 31.7-36.6). Flu vaccination was associated with a lower odds for hospitalization (OR 0.84 CI 0.74-0.95).

Conclusions

We recommend oseltamivir be prescribed to patients when they first present with influenza-like symptoms to reduce the burden on the healthcare system. We also identified reduced odds of hospitalization associated with influenza vaccination, which is already well established, but particularly important this coming flu season.

Point-of-care testing for influenza in a university emergency department: A prospective study

BACKGROUND

Seasonal influenza is a burden for emergency departments (ED). The aim of this study was to investigate whether point-of-care (POC) PCR testing can be used to reduce staff sick days and improve diagnostic and therapeutic procedures.

OBJECTIVES

The aim of this study was to investigate whether point-of-care (POC) PCR testing can be used to reduce staff sick days and improve diagnostic and therapeutic procedures.

METHODS

Using a cross-over design, the cobas® Liat® Influenza A/B POC PCR test (Liat) was compared with standard clinical practice during the 2019/2020 influenza season. All adult patients (aged ≥ 18 years) with fever (≥38°C) and respiratory symptoms were included. Primary end points were the prevalence of influenza infections in the ED and staff sick days. Secondary end points were frequency of antiviral and antibacterial therapy, time between admission and test result or treatment initiation, patient disposition, ED length of stay (LOS), and for inpatients mortality and LOS. Nurses were interviewed about handling and integration of POC testing. The occurrence of SARS-CoV-2 infections coincided with the second half of the study.

RESULTS

A total of 828 patients were enrolled in the study. All 375 patients of the intervention group were tested with Liat, and 103 patients of them (27.6%) tested positive. During the intervention period, staff sick days were reduced by 34.4% (P = .023). Significantly, more patients in the intervention group received antiviral therapy with neuraminidase inhibitors (7.2% vs 3.8%, P = .028) and tested patients received antibiotics more frequently (40.0% vs 31.6%, P = .033). Patients with POC test were transferred to external hospitals significantly more often (5.6% vs 1.3%, P = .01).

CONCLUSION

We conclude that POC testing for influenza is useful in the ED, especially if it is heavily frequented by patients with respiratory symptoms.

The Need for Antiviral Drugs for Pandemic Coronaviruses From a Global Health Perspective

Respiratory failure due to SARS-CoV-2 has caused widespread mortality, creating an urgent need for effective treatments and a long-term need for antivirals for future emergent coronaviruses. Pharmacotherapy for respiratory viruses has largely been unsuccessful with the exception of early treatment of influenza viruses, which shortens symptom duration and prevents infection in close contacts. Under the rapidly evolving circumstances of the COVID-19 pandemic, most clinical trials of experimental treatments in the United States have focused on later stages of the disease process. Worldwide, the clinical studies of the most impactful drugs, remdesivir and dexamethasone in ACTT-1, RECOVERY, and Solidarity, have studied hospitalized patients. Less than half of clinical trials in the U.S. have investigated oral agents, and the majority have taken place in hospitals at a disease stage where the viral load is already decreasing. The limited success of treatments for respiratory viruses and the viral dynamics of COVID-19 suggest that an antiviral therapy with the greatest impact against pandemic coronaviruses would be orally administered, well-tolerated, target a highly conserved viral protein or host-coronavirus interaction and could be used effectively throughout the world, including resource-poor settings. We examine the treatment of respiratory viral infections and current clinical trials for COVID-19 to provide a framework for effective antiviral therapy and prevention of future emergent coronaviruses and call attention to the need for continued preclinical drug discovery.

Point-of-care influenza testing impacts clinical decision, patient flow and length of stay in hospitalized adults

Background

Influenza is difficult to distinguish clinically from other acute respiratory infections. Rapid laboratory diagnosis can help initiate early effective antiviral treatment and isolation. Implementing a novel point-of-care test (POCT) for influenza in the emergency department (ED) could improve treatment and isolation strategies and reduce the length of stay (LOS).

Methods

In a prospective, controlled observational cohort study, we enrolled patients admitted due to acute respiratory illness to 2 public hospitals in Bergen, Norway, one using a rapid POCT for influenza (n = 400), the other (n = 167) using conventional rapid laboratory-based assay.

Results

Prevalence of influenza was similar in the 2 hospitals (154/400, 38% vs 38%, 63/167; P = .863). Most patients in both hospitals received antiviral (83% vs 81%; P = .703) and antibiotic treatment (72% vs 62%; P = .149). Isolation was more often initiated in ED in the hospital using POCT (91% vs 80%; P = .025). Diagnosis by POCT was associated with shorter hospital stay; old age, diabetes, cancer, and use of antibiotics, particularly broad-spectrum antibiotics, were associated with prolonged stay.

Conclusions

POCT implementation in ED resulted in improved targeted isolation and shorter LOS. Regardless of POCT use, most influenza patients received antivirals (>80%) and antibiotics (>69%).

Early Oseltamivir After Hospital Admission Is Associated With Shortened Hospitalization: A 5-Year Analysis of Oseltamivir Timing and Clinical Outcomes

BACKGROUND

Neuraminidase inhibitors (NAIs) are the only effective therapy for influenza, but few studies have assessed the impact of early NAI therapy on clinical outcomes or the patient-level factors that determine early NAI delivery in hospitalized patients.

METHODS

We conducted a retrospective cohort study of all adults hospitalized in a metropolitan tertiary care hospital with confirmed influenza from April 2009 to March 2014. We performed logistic regression to determine patient-level factors that were associated with early NAI therapy. We analyzed the association of early NAI therapy with hospital lengths of stay (LOS) and in-hospital mortality rates using linear and logistic regression, respectively.

RESULTS

In total, 699 patients were admitted with influenza during the 5 influenza seasons. Of those, 582 (83.4%) received NAI therapy; however, only 26.0% received the first dose within 6 hours of hospitalization (early NAI). Patients with diabetes mellitus or pregnancy were more likely to receive early NAI (P = .01, vs. P < .001 in those without these conditions), as were those reporting fever or myalgias at presentation (P = .002, vs. P = .005 without). Immunosuppressed patients were less likely to receive early NAI (P = .04). Early NAI was associated with shorter hospital LOS (P < .001). No patients died in the early NAI group, compared to 18 deaths in the 399 patients receiving NAI after 6 hours (4.5%) and 4 deaths in the 116 patients not receiving NAI (3.4%).

CONCLUSIONS

Over multiple influenza seasons, early NAI therapy was associated with shorter LOS in patients admitted with influenza. This suggests that efforts should focus on facilitating earlier therapy in patients with suspected influenza.

Effect of antiviral treatment in older patients hospitalized with confirmed influenza

Seasonal influenza causes significant morbidity and mortality in people aged ≥65 years. Antiviral treatment can reduce complications and disease severity. The objective of this study was to investigate the effect of antiviral treatment in patients aged ≥65 years hospitalized with confirmed influenza in preventing intensive care unit (ICU) admission or death. A retrospective cohort study was carried out in 20 hospitals from seven Spanish regions during 2013-2015 in patients aged ≥65 years. Hospitalized cases of laboratory-confirmed influenza were selected. To assess the association between antiviral treatment and ICU admission or death, the adjusted odds ratios (aOR) and their 95% confidence intervals (CI) were calculated using multivariate logistic regression. We included 715 hospitalized patients, of whom 640 (87.9%) received antiviral treatment, 77 (10.8%) required ICU admission and 66 (9.2%) died. In the 64-74 years age group, receipt of antiviral treatment ≤48 h (aOR 0.20; 95% CI 0.04-0.89), 3-4 days (aOR 0.23; 95% CI 0.05-0.92) and 5-7 days (aOR 0.24; 95% CI 0.03-0.91) after clinical symptom onset was associated with reduced mortality. Receipt of treatment >7 days after symptom onset was not associated with reduced mortality. No association of antiviral treatment with reduced mortality was observed in the >74 years age group or with the prevention of ICU admission in any age group. Antiviral treatment had a protective effect in avoiding death in patients aged 65-74 years hospitalized due to influenza when administered ≤48 h after symptom onset and when no more than 7 days had elapsed.

Baloxavir treatment of ferrets infected with influenza A(H1N1)pdm09 virus reduces onward transmission

Influenza viruses cause seasonal outbreaks and pose a continuous pandemic threat. Although vaccines are available for influenza control, their efficacy varies each season and a vaccine for a novel pandemic virus manufactured using current technology will not be available fast enough to mitigate the effect of the first pandemic wave. Antivirals can be effective against many different influenza viruses but have not thus far been used extensively for outbreak control. Baloxavir, a recently licensed antiviral drug that targets the influenza virus endonuclease, has been shown to reduce virus shedding more effectively than oseltamivir, a widely used neuraminidase inhibitor drug. Thus it is possible that treatment with baloxavir might also interrupt onward virus transmission. To test this, we utilized the ferret model, which is the most commonly used animal model to study influenza virus transmission. We established a subcutaneous baloxavir administration method in ferrets which achieved similar pharmacokinetics to the approved human oral dose. Transmission studies were then conducted in two different locations with different experimental setups to compare the onward transmission of A(H1N1)pdm09 virus from infected ferrets treated with baloxavir, oseltamivir or placebo to naïve sentinel ferrets exposed either indirectly in adjacent cages or directly by co-housing. We found that baloxavir treatment reduced infectious viral shedding in the upper respiratory tract of ferrets compared to placebo, and reduced the frequency of transmission amongst sentinels in both experimental setups, even when treatment was delayed until 2 days post-infection. In contrast, oseltamivir treatment did not substantially affect viral shedding or transmission compared to placebo. We did not detect the emergence of baloxavir-resistant variants in treated animals or in untreated sentinels. Our results support the concept that antivirals which decrease viral shedding could also reduce influenza transmission in the community.

Neuraminidase Inhibitors and Hospital Length of Stay: A Meta-analysis of Individual Participant Data to Determine Treatment Effectiveness Among Patients Hospitalized With Nonfatal 2009 Pandemic Influenza A(H1N1) Virus Infection

BACKGROUND

The effect of neuraminidase inhibitor (NAI) treatment on length of stay (LoS) in patients hospitalized with influenza is unclear.

METHODS

We conducted a one-stage individual participant data (IPD) meta-analysis exploring the association between NAI treatment and LoS in patients hospitalized with 2009 influenza A(H1N1) virus (A[H1N1]pdm09) infection. Using mixed-effects negative binomial regression and adjusting for the propensity to receive NAI, antibiotic, and corticosteroid treatment, we calculated incidence rate ratios (IRRs) and 95% confidence intervals (CIs). Patients with a LoS of <1 day and those who died while hospitalized were excluded.

RESULTS

We analyzed data on 18 309 patients from 70 clinical centers. After adjustment, NAI treatment initiated at hospitalization was associated with a 19% reduction in the LoS among patients with clinically suspected or laboratory-confirmed influenza A(H1N1)pdm09 infection (IRR, 0.81; 95% CI, .78-.85), compared with later or no initiation of NAI treatment. Similar statistically significant associations were seen in all clinical subgroups. NAI treatment (at any time), compared with no NAI treatment, and NAI treatment initiated <2 days after symptom onset, compared with later or no initiation of NAI treatment, showed mixed patterns of association with the LoS.

CONCLUSIONS

When patients hospitalized with influenza are treated with NAIs, treatment initiated on admission, regardless of time since symptom onset, is associated with a reduced LoS, compared with later or no initiation of treatment.

H1N1 Infection in Pregnancy; A Retrospective Study of Feto-Maternal Outcome and Impact of the Timing of Antiviral Therapy

Background and Objective

H1N1 infection carries an increased risk in pregnancy. Our aim was to study the feto-maternal outcome and the effect of early initiation of therapy.

Methods

This is a retrospective descriptive study. Confirmed infected cases were included. Maternal age, parity, gestational age at diagnosis, presenting symptoms, the time between presentation and starting therapy, ICU admission, and maternal and perinatal outcome were evaluated.

Results

Nineteen confirmed patients were included. Most patients are 31 years old or more. Multiparous patients were 73.68%, and 57.89% were in the third trimester. Most of our patients presented with cough, fever, and chills. Two patients were admitted to the ICU. One of them was a case of maternal mortality. 42.10% of patients were started on therapy only one day after the clinical onset of symptoms. 26.31% delivered before 37 completed weeks. 73.68% delivered beyond term. Around one third delivered vaginally. 45% of babies weighed more than 3 kg. Four babies weighed less than 2 kg. Ninety percent had APGAR scores more than 8 at 1 and 5 minutes after delivery. Twenty-five percent were admitted to the NICU with no neonatal mortalities.

Conclusions

H1N1 influenza A infection in pregnancy is associated with adverse maternal and perinatal outcomes. Medical and public awareness, low threshold for testing suspected pregnant patients, very early initiation of antiviral therapy, and a multidisciplinary approach in our series decreased the overall adverse effects of this infection.

Impact of multiplex molecular assay turn-around-time on antibiotic utilization and clinical management of hospitalized children with acute respiratory tract infections

BACKGROUND

Empiric antibiotic treatment is common among children with acute respiratory tract infections (ARTI), despite infections being predominately viral. The use of molecular respiratory panel assays has become increasingly common for medical care of patients with ARTIs.

STUDY DESIGN

This was a 6-year retrospective, single-centered study of pediatric inpatients who tested positive for an ARTI respiratory pathogen. We examined the relationship between clinical outcomes and whether the patient was tested using the Luminex Respiratory Viral Panel ([RVP]; in-use: Dec. 2009 - Jul. 2012) or Biofire Respiratory Pathogen Panel ([RP]; in-use Aug. 2012 - Jun. 2016). The prevalence and duration of pre-test empiric antibiotics, post-test oseltamivir administration to influenza patients, chest x-rays and length of stay between the two assays was compared.

RESULTS

A total of 5142 patients (1264 RVP; 3878 RP) were included. The median laboratory turn-around-time for RP was significantly shorter than RVP (1.4 vs. 27.1 h, respectively; p < .001). Patients tested with RP were less likely to receive empiric antibiotics (OR: 0.45; p < .001; 95% CI: 0.39, 0.52) and had a shorter duration of empiric broad-spectrum antibiotics (6.4 h vs. 32.9 h; p < .001) compared to RVP patients. RP influenza patients had increased oseltamivir use post- test compared to RVP influenza patients (OR: 13.56; p < .001; 95% CI: 7.29, 25.20).

CONCLUSIONS

Rapid molecular testing positively impacts patient management of ARTIs. Adopting assays with a shorter turn-around-time improves decision making by decreasing empirical antibiotic use and duration, decreasing chest x-rays, increasing timely oseltamivir administration, and reducing length of stay.

The fifth influenza A(H7N9) epidemic: A family cluster of infection in Suzhou city of China, 2016

OBJECTIVE

Influenza A(H7N9) virus is known for its high pathogenicity in human. A family cluster of influenza A(H7N9) virus infection was identified in Suzhou, China. This study aimed to investigate the possibility of human-to-human transmission of the virus and examine the virologic features of this family cluster.

METHODS

The clinical and epidemiologic data of two patients in the family cluster of influenza A(H7N9) virus infection were collected. Viral RNA in samples derived from the two patients, their close contacts, and the environments with likely influenza A(H7N9) virus transmission were tested by real-time reverse transcriptase polymerase chain reaction (rRT-PCR) assay. Hemagglutination inhibition (HI) assay was used to detect virus-specific antibodies. Genetic sequencing and phylogenetic analysis were also performed.

RESULTS

The index patient (Case 1), a 66-year old man, was virologically diagnosed with influenza A(H7N9) virus infection 12days after experiencing influenza-like symptoms, then died of multi-organ failure. His 39-year old daughter (Case 2), denying any other exposure to influenza A(H7N9) virus, became infected with influenza A(H7N9) virus following taking care of her father during his illness. Sequencing viral genomes isolated from the two patients showed nearly identical nucleotide sequence, and genetically resembled the viral genome isolated from a chicken in the wet market where the index patient once visited. All three influenza A(H7N9) viruses shared S138A, G186V, Q226L mutations in HA (H3) protein and a single basic amino acid (PEIPKGR↓G) at the cleavage site.

CONCLUSIONS

Human-to-human transmission of influenza A(H7N9) virus most likely occurred in this household. The three-amino-acid mutations in HA protein were discovered in this study, which might have increased the binding affinity of influenza A(H7N9) virus to the receptor on trachea epithelial cells to facilitate viral transmission among humans.

Safety and effectiveness of neuraminidase inhibitors in situations of pandemic and/or novel/variant influenza: a systematic review of the literature, 2009-15

Objectives

To review systematically the published literature evaluating neuraminidase inhibitor (NI) safety and effectiveness in situations of pandemic and novel/variant influenza.

Methods

We searched six online databases using comprehensive search criteria for observational studies and randomized controlled trials investigating the effects of NI treatment, prophylaxis or outbreak control in patients of all ages.

Results

Overall, 165 studies were included (95% observational), which were generally of low methodological quality due to lack of adjustment for confounding variables. In studies reporting adjusted estimates in general populations, NI treatment appeared likely to be effective against mortality (primarily if administered within 48 h of symptom onset) and potentially effective in reducing pneumonia. NIs appeared effective in reducing secondary transmission when indicated for prophylaxis. Limited, low-quality data suggest NIs are likely safe in general populations and may be safe in pregnant women and children. Data are scarce regarding safety of NIs in adults and high-risk individuals.

Conclusions

Most included studies were observational, statistically underpowered and at high risk of reporting biased and/or confounded effect estimates. NI treatment appeared likely effective in reducing mortality (cause unspecified) and pneumonia in general populations, with increasing benefit when administered with 48 h of symptom onset. NI pre- or post-exposure prophylaxis is likely effective in reducing secondary transmission of influenza in a general population. Our evidence suggests NIs are likely safe to use in the general population; however, data for children and pregnant women are limited. Knowledge gaps persist in specific populations such as Aboriginals, high-risk individuals and the elderly.

The need for strengthening the influenza virus detection ability of hospital clinical laboratories: an investigation of the 2009 pandemic

Most hospital clinical laboratories (HCLs) in China are unable to perform influenza virus detection. It remains unclear whether the influenza detection ability of HCLs influences the early identification and mortality rate of influenza. A total of 739 hospitalized patients with 2009 influenza A (H1N1) virus treated at 65 hospitals between May and December, 2009, in Zhejiang, China, were included based on identifications by HCLs and by public health laboratories (PHLs) of the Centers for Disease Control and Prevention. Of the patients, 407 (55.1%) were male, 17 died, resulting in an in-hospital mortality rate of 2.3%, and 297 patients were identified by HCLs and 442 by PHLs. The results indicated that a 24-hour delay in identification led to a 13% increase in the odds of death (OR = 1.13, P < 0.05). The time between onset and identification (3.9 days) of the HCL cohort was significantly shorter than that of the PHL cohort (4.8 days). The in-hospital mortality rate of the HCL group was significantly lower than that of the PHL group (1.0% vs. 3.2%, P < 0.05). HCL-based detection decreased the in-hospital mortality rate by 68.8%. HCL-based influenza virus detection facilitated early identification and reduced influenza mortality, and influenza detection ability of HCLs should be strengthened.

Postviral Complications: Bacterial Pneumonia

Secondary bacterial pneumonia after viral respiratory infection remains a significant source of morbidity and mortality. Susceptibility is mediated by a variety of viral and bacterial factors, and complex interactions with the host immune system. Prevention and treatment strategies are limited to influenza vaccination and antibiotics/antivirals respectively. Novel approaches to identifying the individuals with influenza who are at increased risk for secondary bacterial pneumonias are urgently needed. Given the threat of further pandemics and the heightened prevalence of these viruses, more research into the immunologic mechanisms of this disease is warranted with the hope of discovering new potential therapies.

The diagnosis and management of respiratory viral infections in cystic fibrosis

INTRODUCTION

Respiratory viruses, such as those that cause influenza and the common cold, are a regular feature of life for the entire human population. Among people with CF, these viruses are associated with prolonged respiratory illness and show a clear association with pulmonary exacerbations which in turn are associated with lung function decline and risk of death. Human rhinovirus is the most commonly encountered respiratory viral pathogen in CF although adenovirus, bocavirus, coronavirus, influenza, parainfluenza, metapneumovirus and respiratory syncytial virus are all also responsible for infections in this population. Areas covered: This article reviews the epidemiology, clinical impact and therapeutic options for respiratory virus infection in both children and adults with CF. Expert commentary: The management of CF to date has largely focused on airway clearance strategies, nutritional support and aggressive antibacterial therapy. We highlight the significant role that respiratory viruses play in CF lung disease and argue that these pathogens represent an under-exploited target in the battle to control patients' symptoms and disease progression.

Impact of HIV on the severity of influenza

Despite current antiretroviral therapy, HIV/AIDS is one of the most prelevant problems in healthcare worldwide. Similarly, influenza viruses are causes of epidemics outbreaks. HIV-infected patients are considered a high risk group for severe influenza infection, although several recent observational studies suggest that not all HIV-infected patients are equally susceptible to complications and that these patients should be stratified by their immunodeficiency status and other factors (such as smoking or comorbidities). Here, we have compiled the most recent data on the impact that HIV has on influenza infection.

Fatal cases of human infection with avian influenza A (H7N9) virus in Shanghai, China in 2013

We retrospectively reviewed the medical records of 17 fatal H7N9 cases in Shanghai in 2013, analyzed clinical variables and described their clinical and epidemiologic characteristics. The median age was 73 years, and 82.4% had underlying medical conditions. The most frequent symptoms were fever (100%), followed by productive cough (47.1%) and dry cough (35.5%). Thirteen (76.5%) patients had dyspnea or respiratory distress, five (29.4%) had shock, and four (23.5%) had acute kidney injury. Seventeen (100.0%) patients had lymphopenia. Involvement of both lungs was found by chest radiography in 14 (82.4%) patients at presentation. Fifteen (88.2%) patients were hospitalized. The median times from illness onset to hospitalization and to diagnosis confirmation were both six days. Eleven (64.7%) patients were admitted to the intensive care unit. Sixteen (94.1%) patients were treated with oseltamivir. The median time from illness onset to oseltamivir treatment was six days. Among six patients for whom the duration of viral shedding was available, the median duration of viral shedding after oseltamivir treatment was 17 days. The median time from illness onset to death was 11 days. Refractory hypoxemia accounted for most deaths. The clinical and epidemiologic characteristics in the Shanghai fatal series of patients do not differ from other reports of H7N9 patients in China. This investigation reflects a delay in the diagnosis and antiviral treatment of H7N9 patients in the early stage of the epidemic in Shanghai. Late antiviral treatment and a long duration of viral shedding may be associated with a fatal outcome in these patients.

Estimating the United States demand for influenza antivirals and the effect on severe influenza disease during a potential pandemic

Following the detection of a novel influenza strain A(H7N9), we modeled the use of antiviral treatment in the United States to mitigate severe disease across a range of hypothetical pandemic scenarios. Our outcomes were total demand for antiviral (neuraminidase inhibitor) treatment and the number of hospitalizations and deaths averted. The model included estimates of attack rate, healthcare-seeking behavior, prescription rates, adherence, disease severity, and the potential effect of antivirals on the risks of hospitalization and death. Based on these inputs, the total antiviral regimens estimated to be available in the United States (as of April 2013) were sufficient to meet treatment needs for the scenarios considered. However, distribution logistics were not examined and should be addressed in future work. Treatment was estimated to avert many severe outcomes (5200-248,000 deaths; 4800-504,000 hospitalizations); however, large numbers remained (25,000-425,000 deaths; 580,000-3,700,000 hospitalizations), suggesting that the impact of combinations of interventions should be examined.

Rates and effectiveness of antiviral use among hospitalized influenza patients

The influenza virus is currently a global public health problem. There are several thousand cases of classic and newly emerging atypical influenza virus infections around the world annually. Prevention, early diagnosis and treatment are the keys to managing influenza outbreaks. Some influenza treatments have proven to be more useful than others. A standard antiviral drug has been developed and is recommended for the management of hospitalized influenza patients. This article briefly outlines the rates and effectiveness of antiviral use among hospitalized influenza patients. It also discusses some important considerations regarding controversial issues and future perspectives on antiviral use for the management of hospitalized influenza patients.

Does Influenza Vaccination Modify Influenza Severity? Data on Older Adults Hospitalized With Influenza During the 2012-2013 Season in the United States

BACKGROUND

Some studies suggest that influenza vaccination might be protective against severe influenza outcomes in vaccinated persons who become infected. We used data from a large surveillance network to further investigate the effect of influenza vaccination on influenza severity in adults aged ≥50 years who were hospitalized with laboratory-confirmed influenza.

METHODS

We analyzed influenza vaccination and influenza severity using Influenza Hospitalization Surveillance Network (FluSurv-NET) data for the 2012-2013 influenza season. Intensive care unit (ICU) admission, death, diagnosis of pneumonia, and hospital and ICU lengths of stay served as measures of disease severity. Data were analyzed by multivariable logistic regression, parametric survival models, and propensity score matching (PSM).

RESULTS

Overall, no differences in severity were observed in the multivariable logistic regression model. Using PSM, adults aged 50-64 years (but not other age groups) who were vaccinated against influenza had a shorter length of ICU stay than those who were unvaccinated (hazard ratio for discharge, 1.84; 95% confidence interval, 1.12-3.01).

CONCLUSIONS

Our findings show a modest effect of influenza vaccination on disease severity. Analysis of data from seasons with different predominant strains and higher estimates of vaccine effectiveness are needed.

Hospital Readmissions Among Children With H1N1 Influenza Infection

OBJECTIVES

To describe readmissions among children hospitalized with H1N1 (influenza subtype, hemagglutinin1, neuraminidase 1) pandemic influenza and secondarily to determine the association of oseltamivir during index hospitalization with readmission.

METHODS

We reviewed data from 42 freestanding children's hospitals contributing to the Pediatric Health Information System from May through December 2009 when H1N1 was the predominant influenza strain. Children were divided into 2 groups by whether they experienced complications of influenza during index hospitalization. Primary outcome was readmission at 3, 7, and 30 days among both patient groups. Secondary outcome was the association of oseltamivir treatment with readmission.

RESULTS

The study included 8899 children; 6162 patients had uncomplicated index hospitalization, of whom 3808 (61.8%) received oseltamivir during hospitalization, and 2737 children had complicated influenza, of whom 1055 (38.5%) received oseltamivir. Median 3-, 7-, and 30-day readmission rates were 1.6%, 2.5%, and 4.7% for patients with uncomplicated index hospitalizations and 4.3%, 5.8%, and 10.3% among patients with complicated influenza. The 30-day readmission rates did not differ by treatment group among patients with uncomplicated influenza; however, patients with complicated index hospitalizations who received oseltamivir had lower all-cause 30-day readmissions than untreated patients. The most common causes of readmission were pneumonia and asthma exacerbations.

CONCLUSIONS

Oseltamivir use for hospitalized children did not decrease 30-day readmission rates in children after uncomplicated index hospitalization but was associated with a lower 30-day readmission rate among children with complicated infections during the 2009 H1N1 pandemic. Readmission rates for children who had complicated influenza infection during index hospitalizations are high.

Viral-bacterial interactions-therapeutic implications

Viral and bacterial respiratory tract infections are a leading cause of morbidity and mortality worldwide, despite the development of vaccines and potent antibiotics. Frequently, viruses and bacteria can co‐infect the same host, resulting in heightened pathology and severity of illness compared to single infections. Bacterial superinfections have been a significant cause of death during every influenza pandemic, including the 2009 H1N1 pandemic. This review will analyze the epidemiology and global impact of viral and bacterial co‐infections of the respiratory tract, with an emphasis on bacterial infections following influenza. We will next examine the mechanisms by which viral infections enhance the acquisition and severity of bacterial infections. Finally, we will discuss current management strategies for diagnosing and treating patients with suspected or confirmed viral‐bacterial infections of the respiratory tract. Further investigation into the interactions between viral and bacterial infections is necessary for developing new therapeutic approaches aimed at mitigating the severity of co‐infections.

Respiratory viral infections among hospitalized adults: experience of a single tertiary healthcare hospital

Background

Following the 2009 H1N1 pandemic, there have been a large number of studies focusing on the epidemiology and outcomes of influenza A infection; however, there have been fewer studies focused on other respiratory viral infections.

Objectives

To define the epidemiology and outcomes of non-influenza respiratory viral infections in hospitalized adults.

Patients/Methods

Data on all patients ≥18 years of age with a positive molecular respiratory viral assay who were hospitalized at a single tertiary healthcare system in Chicago, IL, from retrospectively collected and analyzed.

Results

Over the study period, 503 of 46 024 (1·1%) admitted patients had a positive RVP result. Human rhinovirus was the most commonly detected virus followed by influenza A, human metapneumovirus, respiratory syncytial virus, and parainfluenza virus, adenovirus, and influenza B, respectively. Infection in immunocompromised patients was associated with a higher rate of progression to pneumonia and death.

Conclusions

Non-influenza respiratory viral infections are commonly detected among adults admitted to the hospital and can cause serious illness. The data can inform the prioritization of research into novel antiviral therapies for these infections.

Antiviral treatment and vaccination for influenza A(H1N1)pdm09 virus: lessons learned from the pandemic

The influenza pandemic that was declared by the World Health Organization in June 2009 created a new scenario for the use of influenza antivirals and vaccination. The new strain, influenza A(H1N1)pdm09, was resistant to amantadine and rimantadine, and the most frequently used antiviral was oseltamivir. Randomized studies were not performed comparing neuraminidase inhibitors with placebo. Nevertheless, experience from prospective and retrospective cohorts indicated that these drugs were useful for improving the prognosis of patients admitted to hospitals, especially for those with more severe disease. Treatment with oseltamivir was associated with a reduction in days of fever, length of hospital stay, use of mechanical ventilation and mortality. Treatment was more effective if it was begun within the first 48 h after the onset of symptoms, but it was also useful if begun later. A safe and effective vaccine to prevent disease from this new influenza strain was available in developed countries soon after the pandemic began; thus, the rate of adverse effects was comparable to that of seasonal influenza vaccines. The main barrier to its use was the concern of target populations about its necessity and safety. Therefore, the challenges for future pandemics will be to increase the population coverage of the vaccine in developed countries and to make it affordable for developing countries.

Influenza A(H1N1)pdm09-related pneumonia and other complications

Influenza A(H1N1)pdm09 virus infection was associated with significant morbidity, mainly among children and young adults. The majority of patients had self-limited mild-to-moderate uncomplicated disease. However, some patients developed severe illness and some died. In addition to respiratory complications, several complications due to direct and indirect effects on other body systems were associated with influenza A(H1N1)pdm09 virus infection. The main complications reported in hospitalized adults with influenza A(H1N1)pdm09 were pneumonia (primary influenza pneumonia and concomitant/secondary bacterial pneumonia), exacerbations of chronic pulmonary diseases (mainly chronic obstructive pulmonary disease and asthma), the need for intensive unit care admission (including mechanical ventilation, acute respiratory distress syndrome and septic shock), nosocomial infections and acute cardiac events. In experimentally infected animals, the level of pulmonary replication of the influenza A(H1N1)pdm09 virus was higher than that of seasonal influenza viruses. Pathological studies in autopsy specimens indicated that the influenza A(H1N1)pdm09 virus mainly targeted the lower respiratory tract, resulting in diffuse alveolar damage (edema, hyaline membranes, inflammation, and fibrosis), manifested clinically by severe acute respiratory distress syndrome with refractory hypoxemia. Influenza A(H1N1)pdm09-related pneumonia and other complications were associated with increased morbidity and mortality among hospitalized patients.

Influenza A(H1N1)pdm09: beyond the pandemic

On August 2010, the World Health Organization declared the end to the 2009 A(H1N1) pandemic. However, influenza A(H1N1)pdm09 continues to circulate as a seasonal virus. Different viruses have predominated in different parts of the world. To date, influenza A(H1N1)pdm09 has demonstrated little antigenic drift, and its oseltamivir resistance has remained low. In some countries, a higher number of severe cases of influenza A(H1N1)pdm09 infection were documented during the 2010-2011 season than during the pandemic period. In addition, delays in oseltamivir administration, higher ages and comorbidities and low vaccination rates in patients with influenza A(H1N1)pdm09 infection were found during the first postpandemic season. Therefore, physicians should carefully consider the pandemic virus as a possible causative agent in patients with influenza-like illnesses admitted to emergency departments. In addition, surveillance systems and vaccination campaigns should continue after the pandemic period.

Risk factors for prolonged H1N1 influenza among hospitalized patients

In our study, 50% of 42 hospitalized patients with 2009 H1N1 pandemic influenza experienced symptoms longer than 1 week. Older age and delay in oseltamivir initiation were associated with prolonged illness. Patients with pneumonia and fever ≥7 days were more likely to have polymerase chain reaction-positive nasopharyngeal swabs beyond 1 week.

Neuraminidase inhibitors for critically ill children with influenza

OBJECTIVE

Timely treatment with neuraminidase inhibitor (NAI) drugs appears to improve survival in adults hospitalized with influenza. We analyzed California surveillance data to determine whether NAI treatment improves survival in critically ill children with influenza.

METHODS

We analyzed data abstracted from medical records to characterize the outcomes of patients aged 0 to 17 years hospitalized in ICUs with laboratory-confirmed influenza from April 3, 2009, through September 30, 2012.

RESULTS

Seven hundred eighty-four influenza cases aged <18 years hospitalized in ICUs had information on treatment. Ninety percent (532 of 591) of cases during the 2009 H1N1 pandemic (April 3, 2009-August 31, 2010) received NAI treatment compared with 63% (121 of 193) of cases in the postpandemic period (September 1, 2010-September 30, 2012; P < .0001). Of 653 cases NAI-treated, 38 (6%) died compared with 11 (8%) of 131 untreated cases (odds ratio = 0.67, 95% confidence interval: 0.34-1.36). In a multivariate model that included receipt of mechanical ventilation and other factors associated with disease severity, the estimated risk of death was reduced in NAI-treated cases (odds ratio 0.36, 95% confidence interval: 0.16-0.83). Treatment within 48 hours of illness onset was significantly associated with survival (P = .04). Cases with NAI treatment initiated earlier in illness were less likely to die.

CONCLUSIONS

Prompt treatment with NAIs may improve survival of children critically ill with influenza. Recent decreased frequency of NAI treatment of influenza may be placing untreated critically ill children at an increased risk of death.

Early therapy with neuraminidase inhibitors for influenza A (H1N1) pdm 2009 infection

BACKGROUND

Neuraminidase inhibitors have been reported to decrease mortality in patients infected with influenza A (H1N1) pdm 2009 (H1N1 pdm09), but it is not clear whether they are effective against H1N1pdm09 in apparently healthy children.

METHODS

The effect of early treatment with neuraminidase inhibitors on 70 otherwise healthy children with possible H1N1 pdm09 (pH1N1pdm09) infection was investigated. The children were simultaneously treated with a neuraminidase inhibitor (oseltamivir or zanamivir) and maoto, a Japanese traditional herbal medicine, which had been reported to be effective against seasonal influenza. Clinical severity was assessed using patient history, namely the worst values for clinical vital signs and laboratory data on admission. After refining these parameters with univariate, decision tree and multiple regression analysis, mean covariance structure equation analysis was used to investigate the association of estimated clinical severity to the selected parameters.

RESULTS

Total path analysis using a Bayesian method indicated that the estimated clinical severity of pH1N1pdm09 was positively associated with maximum body temperature, pulse rate, respiration rate, duration necessary for defervescence, admission duration and log urinary β2-microglobulin/creatinine level, and negatively associated with age and the presence and duration of treatment with the neuraminidase inhibitor in the outpatient clinic.

CONCLUSIONS

This study provides the first clinical evidence that early treatment with neuraminidase inhibitors in outpatient clinic decreased the estimated clinical severity of pH1N1pdm09 in apparently otherwise healthy pediatric inpatients.

Advances in antibiotic therapy for community-acquired pneumonia

PURPOSE OF REVIEW

Community-acquired pneumonia (CAP) is a major public health problem all over the world. The increasing number of antibiotic-resistant bacteria is a matter of concern for physicians when choosing antibiotic treatment in patients with CAP. This review focuses on the current recommendations of antibiotic treatment, recent information concerning antibiotic resistance of pathogens, and the advances in antibiotic therapy in the field of CAP.

RECENT FINDINGS

A significant increase in the frequency of resistance to the antibiotics commonly used against causative pathogens of CAP, such as β-lactams or macrolides, has been reported in recent years. At present, the prevalence of fluoroquinolone resistance in Streptococcus pneumoniae remains low. Community-acquired methicillin-resistant Staphylococcus aureus and influenza A(H1N1)pdm09 have been reported as causes of severe CAP. Several newly-developed antibiotics, including cepholosporins, ketolides and quinolones, present marked activity in vitro against the main causative pathogens of CAP. Many randomized controlled trials have demonstrated equivalent efficacy of the newer antibiotics compared with conventional antimicrobial therapy in mild-to-moderate CAP.

SUMMARY

An increase of resistance to the antibiotics used in CAP has been documented over the years. Several new antibiotics have been developed for treating CAP, with promising results. However, data regarding their efficacy and safety in patients with severe CAP are lacking.

Clinical and radiological characteristics of 2009 H1N1 influenza associated pneumonia in young male adults

PURPOSE

Pneumonia was an important cause of death in 2009 H1N1 influenza pandemic (pH1N1). Clinical characteristics of pH1N1 have been described well, but discriminative characteristics suggesting pH1N1 infection in pneumonia patients are not evident today. We evaluated differences between clinical and radiologic characteristics for those associated and not associated with pH1N1 influenza during the pandemic period.

MATERIALS AND METHODS

We reviewed all patients with pneumonia who visited the Armed Forces Capital Hospital between July 2009 and February 2010. During this period, all pneumonia patients were tested for pH1N1 by reverse transcription-polymerase chain reaction (RT-PCR) using nasopharyngeal specimens.

RESULTS

In total, 98 patients with pneumonia were enrolled. Their median age was 20 years and all patients were males. Forty-nine (50%) of patients had pH1N1 infection and the others (50%) had negative results in pH1N1 RT-PCR. Patients with pH1N1 infection complained of dyspnea more commonly (83.3% vs. 29.0%; p<0.001), had higher Acute Physiology and Chronic Health Evaluation (APACHE) II scores [5 (range, 0-12) vs. 3 (range, 0-11); p<0.01], fewer days of prehospital illness [2 (range, 0-10) vs. 4 (range, 0-14); p=0.001], and a higher chance of bilateral infiltrates on chest X-ray (CXR) (67.3% vs. 14.3%; p<0.001) and ground-glass opacity (GGO) lesions on computed tomography (CT; 48.9% vs. 22.0%; p<0.001) than patients without pH1N1 infection.

CONCLUSION

Dyspnea, bilateral infiltrates on CXR, and GGO on CT were dominant features in pH1N1-associated pneumonia. Understanding these characteristics can help selection of patients who require prompt antiviral therapy.

Report of the first Asia-Pacific Forum on antiviral treatment of influenza, Asia-Pacific Alliance for the Control of Influenza, Bangkok, 14 June 2012

On 14 June 2012, the Asia–Pacific Alliance for the Control of Influenza (APACI) convened the first Antiviral Forum jointly with the Influenza Foundation of Thailand and the Thailand Department of Disease Control. The goals of the meeting were to improve pandemic planning in the region from lessons learned during the 2009 pandemic, particularly with regard to the safety and efficacy of antiviral use; gain a better understanding of the therapeutic use of antivirals in seasonal influenza; review and analyse the official influenza control policies of Asia–Pacific countries and evidence gaps to support policy development; and to establish collaborative relationships to promote best practices in the use of antivirals for the treatment of influenza. The urgent need for education highlighting the importance of influenza and the benefits of antiviral drug use in the Asia–Pacific region was identified.

Management of influenza infection in solid-organ transplant recipients: consensus statement of the Group for the Study of Infection in Transplant Recipients (GESITRA) of the Spanish Society of Infectious Diseases and Clinical Microbiology (SEIMC) and the Spanish Network for Research in Infectious Diseases (REIPI)

BACKGROUND

Solid organ transplant (SOT) recipients are at greater risk than the general population for complications and mortality from influenza infection.

METHODS

Researchers and clinicians with experience in SOT infections have developed this consensus document in collaboration with several Spanish scientific societies and study networks related to transplant management. We conducted a systematic review to assess the management and prevention of influenza infection in SOT recipients. Evidence levels based on the available literature are given for each recommendation. This article was written in accordance with international recommendations on consensus statements and the recommendations of the Appraisal of Guidelines for Research and Evaluation II (AGREE II).

RESULTS

Recommendations are provided on the procurement of organs from donors with suspected or confirmed influenza infection. We highlight the importance of the possibility of influenza infection in any SOT recipient presenting upper or lower respiratory symptoms, including pneumonia. The importance of early antiviral treatment of SOT recipients with suspected or confirmed influenza infection and the necessity of annual influenza vaccination are emphasized. The microbiological techniques for diagnosis of influenza infection are reviewed. Guidelines for the use of antiviral prophylaxis in inpatients and outpatients are provided. Recommendations for household contacts of SOT recipients with influenza infection and health care workers in close contact with transplant patients are also included. Finally antiviral dose adjustment guidelines are presented for cases of impaired renal function and for pediatric populations.

CONCLUSIONS

The latest scientific information available regarding influenza infection in the context of SOT is incorporated into this document.

Reduced incidence of pneumonia in influenza-vaccinated solid organ transplant recipients with influenza disease

Clin Microbiol Infect

Abstract

Whether influenza vaccination influences the severity of illness in cases of clinical failure in solid organ transplant (SOT) recipients receiving influenza vaccine has not been extensively studied. Our goal was to evaluate the frequency of influenza vaccination among SOT recipients with influenza disease and its impact on the illness severity during the 2010–2011 season. Adult SOT recipients with confirmed influenza infection were included from December 2010 to April 2011. Follow‐up data were recorded and antibody titres were determined using a microneutralization assay. Sixty‐four SOT recipients were included in the study, ten (15.6%) with severe disease, requiring admission to intensive care units, of whom four (6.3%) died. In all, 34 (53.1%) received the 2010–2011 seasonal influenza vaccine and 32 (50.0%) received the 2009‐H1N1 pandemic vaccine, and none had detectable antibodies against influenza at the time of diagnosis of influenza infection. Twenty‐three (67.6%) of the patients that received the vaccine required hospital admission and presented less dyspnoea (10, 29.4% versus 14 (50.0%), p 0.09) and pneumonia (8, 23.8% versus 15, 50.0%, p 0.03, relative risk 0.3, 95% CI 0.1–0.9) than unvaccinated patients, with relative risk reductions of 60% and 70%, respectively. Although influenza vaccination confers protection on SOT recipients against developing influenza pneumonia, the rate of clinical failure is still high. New strategies to improve influenza immunization are needed for this group of patients.

A large, population-based study of 2009 pandemic Influenza A virus subtype H1N1 infection diagnosis during pregnancy and outcomes for mothers and neonates

BACKGROUND

Pregnant women were at increased risk for serious outcomes of 2009 pandemic influenza A virus subtype H1N1 (influenza A[H1N1]pdm09) infection, but little is known about the overall impact of the pandemic on neonatal and maternal outcomes.

METHODS

We identified live births that occurred from 1 July 2008 through 31 May 2010 in 5 Kaiser Permanente regions. Pregnant women were considered to have influenza if they had a positive result of a laboratory test for influenza virus or if they received a diagnosis of influenza during a period in which seasonal influenza virus or A(H1N1)pdm09 was the predominant circulating virus.

RESULTS

There were 111 158 births from 109 015 pregnancies involving 107 889 mothers; 368 pregnant women (0.3%) received a diagnosis of influenza due to seasonal virus, and 959 (0.9%) received a diagnosis of influenza due to A(H1N1)pdm09; 107 688 did not receive an influenza diagnosis. Pregnant women with influenza due to A(H1N1)pdm09 were more likely than women with seasonal influenza infection to be hospitalized within 30 days of the diagnosis (27% vs 12%; odds ratio [OR], 2.84 [95% confidence interval {CI}, 2.01-4.02]). Pregnant women with A(H1N1)pdm09 who started antiviral treatment ≥2 days after the diagnosis were significantly more likely to be hospitalized than those who started antiviral treatment <2 days after diagnosis (OR, 3.43 [95% CI, 1.55-7.56]). Mothers with seasonal influenza virus infection had an increased risk for having a small-for-gestational-age infant (OR, 1.59 [95% CI, 1.15-2.20]).

CONCLUSIONS

In this large, geographically diverse population, A(H1N1)pdm09 infection increased the risk for hospitalization during pregnancy. Late initiation of antiviral treatment was also associated with an increased risk for hospitalization.

Treatment with neuraminidase inhibitors for critically ill patients with influenza A (H1N1)pdm09

BACKGROUND

Neuraminidase inhibitor (NAI) antiviral drugs can shorten the duration of uncomplicated influenza when administered early (<48 hours after illness onset) to otherwise healthy outpatients, but the optimal timing of effective therapy for critically ill patients is not well established.

METHODS

We analyzed California surveillance data to characterize the outcomes of patients in intensive care units (ICUs) treated with NAIs for influenza A(H1N1)pdm09 (pH1N1). Demographic and clinical data were abstracted from medical records, using standardized case report forms.

RESULTS

From 3 April 2009 through 10 August 2010, 1950 pH1N1 cases hospitalized in ICUs were reported. Of 1859 (95%) with information available, 1676 (90%) received NAI treatment, and 183 (10%) did not. The median age was 37 years (range, 1 week-93 years), 1473 (79%) had ≥1 comorbidity, and 492 (26%) died. The median time from symptom onset to starting NAI treatment was 4 days (range, 0-52 days). NAI treatment was associated with survival: 107 of 183 untreated case patients (58%) survived, compared with 1260 of 1676 treated case patients (75%; P ≤ .0001). There was a trend toward improved survival for those treated earliest (P < .0001). Treatment initiated within 5 days after symptom onset was associated with improved survival compared to those never treated (P < .05).

CONCLUSIONS

NAI treatment of critically ill pH1N1 patients improves survival. While earlier treatment conveyed the most benefit, patients who started treatment up to 5 days after symptom onset also were more likely to survive. Further research is needed about whether starting NAI treatment >5 days after symptom onset may also convey benefit.

Antivirals for treatment of influenza: a systematic review and meta-analysis of observational studies

BACKGROUND

Systematic reviews of randomized, controlled trials in patients with influenza suggest a lack of evidence about the effects of antiviral therapy on several patient-important outcomes of influenza.

PURPOSE

To systematically review observational studies for benefits and harms of oseltamivir, zanamivir, amantadine, or rimantadine in the treatment of influenza.

DATA SOURCES

MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials, CINAHL, SIGLE, the Chinese Biomedical Literature Database, Panteleimon, and LILACS up to November 2010; contact with pharmaceutical companies; and reference lists.

STUDY SELECTION

Observational studies in any language that compared single antiviral therapy with no therapy or other antiviral therapy, or that had no comparator, for influenza or influenza-like illness.

DATA EXTRACTION

Two independent investigators extracted data. Confidence in the estimates of the obtained effects (quality of evidence) was assessed by using the Grading of Recommendations Assessment, Development, and Evaluation approach.

DATA SYNTHESIS

74 studies fulfilled the inclusion criteria. Meta-analyses of the few studies providing effects with adjustment for confounders suggest that, in high-risk populations, oral oseltamivir may reduce mortality (odds ratio, 0.23 [95% CI, 0.13 to 0.43]; low-quality evidence), hospitalization (odds ratio, 0.75 [CI, 0.66 to 0.89]; low-quality evidence), and duration of symptoms (33 hours [CI, 21 to 45 hours]; very low-quality evidence) compared with no treatment. Earlier treatment with oseltamivir was generally associated with better outcomes. Inhaled zanamivir may lead to shorter symptom duration (23 hours [CI, 17 to 28 hours]; moderate-quality evidence) and fewer hospitalizations (odds ratio, 0.66 [CI, 0.37 to 1.18]) but more complications than no treatment. Direct comparison of oral oseltamivir and inhaled zanamivir suggests no important differences in key outcomes. Data from 1 study suggest that oral amantadine may reduce mortality and pneumonia associated with influenza A. No included study evaluated rimantadine.

LIMITATIONS

Mortality was assessed in high-risk patients, and generalizability is limited. The overall body of evidence is limited by risk for confounding and selection, reporting, and publication bias.

CONCLUSION

Therapy with oral oseltamivir and inhaled zanamivir may provide a net benefit over no treatment of influenza. However, as with the randomized trials, the confidence in the estimates of the effects for decision making is low to very low. PRIMARY FUNDING SOURCES: World Health Organization and McMaster University.

Antivirals and resistance: influenza virus

Influenza causes annual epidemics of respiratory viral infections are associated with significant morbidity and mortality. Influenza vaccines have been shown to reduce the risk of infection and mitigate against some of the virus' sequellae. Likewise, two classes of antivirals, the adamantanes (amantadine and rimantadine) and the neuraminidase inhibitors (laninamivir, oseltamivir, peramivir, and zanamivir) are currently approved for the prevention and treatment of influenza; several other classes of antivirals and immune modulators are also currently under investigation. One of the greatest challenges to our armamentarium of antivirals is the emergence of resistant mutants. In this paper, we will review the currently approved and investigational antiviral agents and the mechanisms of resistance that impact their activity.