Epidemiology of Hospital Admissions with Influenza during the 2013/2014 Northern Hemisphere Influenza Season: Results from the Global Influenza Hospital Surveillance Network

Considerations when treating influenza infections with oseltamivir

INTRODUCTION

Since the coronavirus disease 2019-mandated social distancing policy has been lifted worldwide, the circulation of influenza is expected to resume. Currently, oseltamivir is approved as the first-line agent for influenza prevention and treatment.

AREAS COVERED

This paper reviews the updated evidence in the pharmacology, resistance mechanisms, clinical pharmacy management, and real-world data on oseltamivir for influenza.

EXPERT OPINION

Oseltamivir is an oral prodrug of oseltamivir carboxylate, an influenza A and B neuraminidase inhibitor. Recently, the therapeutic efficacy of oseltamivir has been demonstrated in several trials. Oseltamivir is generally well-tolerated but may lead to neuropsychiatric events and bleeding. Oseltamivir-resistant influenza virus has been associated with the H275Y mutation in the influenza A(H1N1)pdm09 virus, while most strains are still sensitive to oseltamivir. Dose adjustment for oseltamivir should be based on creatinine clearance and body weight in pediatric patients with renal failure. According to real-world data from Nanfang Hospital, the annual number of patients prescribed oseltamivir declined from 35,711 in 2019 to 8,971 in 2020, with marked increases in 2022 (20,213) and 2023 (18,071). Among the 206 inpatients, children aged < 6 years who were treated with oseltamivir had the shortest duration to defervescence.

Vaccination in Patients with Liver Cirrhosis: A Neglected Topic

Patients with liver cirrhosis, due to their weakened innate and adaptive immunity, are more prone to frequent and severe vaccine-preventable infections. Moreover, impaired adaptive immunity results in a limited antibody response to vaccines. Despite this suboptimal antibody response, vaccines have proven to be very effective in reducing severe outcomes and deaths in these patients. In the Western world, regulatory authorities and scientific liver societies (e.g., AASLD and EASL) have recommended vaccinations for cirrhotic patients. However, despite these strong recommendations, vaccine coverage remains suboptimal. Improving vaccine effectiveness and safety information, providing comprehensive counseling to patients, fact-checking to combat fake news and disinformation and removing barriers to vaccination for disadvantaged individuals may help overcome the low coverage rate. In view of this, vaccines should be administered early in the course of chronic liver diseases, as their efficacy declines with the increasing severity of the disease.

Prevention of influenza complications in patients with liver disease: a retrospective cohort study

Introduction

Patients with chronic liver disease are highly prone to acquiring influenza infection diseases and experiencing associated complications. National and international guidelines recommend the influenza vaccine for patients with liver disorders to reduce the risk of influenza complications. Our study aims to evaluate the risk of flu complications faced by patients with liver disease and assess influenza vaccination coverage.

Methods

The archive of hospital discharge forms was used to define the list of Apulian patients with liver disease, considering data from 2017 through 2022. The vaccination status of these patients was assessed via data collected from the Regional Immunization Database. We focused on influenza vaccine shots administered during the 2020/21, 2021/22, and 2022/23 flu seasons.

Results

A declining trend across the flu seasons was observed, with a VC of 49.5% in the 2020/21 flu season, 48.1% in the 2021/22 season, and 45.0% in the 2022/23 season. Subjects with multiple comorbidities have higher vaccination rates. Additionally, the multivariate models demonstrate that vaccination compliance increases with age and is strongly associated with having received a previous influenza vaccine shot.

Conclusion

The VC rates reported in our study are unsatisfactory and did not reach the minimum achievable goal (75%) the Italian Ministry of Health set. A multifactorial approach is required to raise the immunization rates and therefore protect the patients from the influenza-associated risk of collateral liver damage; the role of gastroenterologists and hepatologists is crucial, as their responsibilities should extend beyond patient care to the prevention of complications after infectious diseases.

Frequency of respiratory virus-associated infection among children and adolescents from a tertiary-care hospital in Mexico City

Acute respiratory infections (ARIs) are a major cause of morbidity and mortality among children. The causative pathogens show geographic and seasonal variations. We retrospectively evaluated the frequency and seasonality of respiratory pathogens in children and adolescents (age: 0-19 years) with ARIs treated between January 1, 2021, and March 31, 2022, at a single center in Mexico. Out of 2400 patients, 1,603 were diagnosed with SARS-CoV-2 infection and 797 were diagnosed with other common respiratory pathogens (CRPs). Of the 797 patients, 632 were infected with one CRP and 165 with > 2 CRPs. Deaths occurred only in SARS-CoV-2-infected patients. Rhinovirus/Enterovirus, respiratory syncytial virus B, and parainfluenza virus 3 were the most prevalent in cases with single and multiple infections. CRP showed a high frequency between autumn and winter of 2021, with higher incidence of hospitalization compared to COVID-19. The main comorbidities were immunosuppression, cardiovascular disease (CD), and asthma. The frequency of CRPs showed a downward trend throughout the first half of 2021. CRPs increased in single- and co-infection cases between the fourth and fifth waves of COVID-19, probably due to decreased nonpharmaceutical interventions and changes in diagnostic tests. Age, cyanosis (symptom), and immunosuppression (comorbidity) were found to differentiate between SARS-CoV-2 infection and CRP infection.

Characteristics and outcomes of COVID-19 patients with and without asthma from the United States, South Korea, and Europe

Objective: Large international comparisons describing the clinical characteristics of patients with COVID-19 are limited. The aim of the study was to perform a large-scale descriptive characterization of COVID-19 patients with asthma.Methods: We included nine databases contributing data from January to June 2020 from the US, South Korea (KR), Spain, UK and the Netherlands. We defined two cohorts of COVID-19 patients ('diagnosed' and 'hospitalized') based on COVID-19 disease codes. We followed patients from COVID-19 index date to 30 days or death. We performed descriptive analysis and reported the frequency of characteristics and outcomes in people with asthma defined by codes and prescriptions.Results: The diagnosed and hospitalized cohorts contained 666,933 and 159,552 COVID-19 patients respectively. Exacerbation in people with asthma was recorded in 1.6-8.6% of patients at presentation. Asthma prevalence ranged from 6.2% (95% CI 5.7-6.8) to 18.5% (95% CI 18.2-18.8) in the diagnosed cohort and 5.2% (95% CI 4.0-6.8) to 20.5% (95% CI 18.6-22.6) in the hospitalized cohort. Asthma patients with COVID-19 had high prevalence of comorbidity including hypertension, heart disease, diabetes and obesity. Mortality ranged from 2.1% (95% CI 1.8-2.4) to 16.9% (95% CI 13.8-20.5) and similar or lower compared to COVID-19 patients without asthma. Acute respiratory distress syndrome occurred in 15-30% of hospitalized COVID-19 asthma patients.Conclusion: The prevalence of asthma among COVID-19 patients varies internationally. Asthma patients with COVID-19 have high comorbidity. The prevalence of asthma exacerbation at presentation was low. Whilst mortality was similar among COVID-19 patients with and without asthma, this could be confounded by differences in clinical characteristics. Further research could help identify high-risk asthma patients.[Box: see text]Supplemental data for this article is available online at https://doi.org/10.1080/02770903.2021.2025392 .

Association between Influenza and COVID-19 Viruses and the Risk of Atherosclerosis: Meta-Analysis Study and Systematic Review

There is a lot of evidence to suggest that patients infected with the COVID-19 and influenza viruses are at risk of atherosclerosis. Additionally, there are heterogeneous studies on the risk of arthrosclerosis in patients infected with the influenza and COVID-19 viruses. We conducted a case−control and cross-sectional study and examined the association between the risk of atherosclerosis, and influenza virus (IV-A and IV-B) and COVID-19 infections in this study. We searched for keywords such as influenza virus, COVID-19 and atherosclerosis in English and Persian in well-known databases such as PubMed, SID, Magiran and Google Scholar. In this study, we analyzed the information using a meta-analysis, the random effect model, the I2 index and STAT (version 11.2). The results from the analysis of ten studies on influenza virus and nine studies on COVID-19 reviewed individually (totaling 6428 samples for influenza virus infections and 10,785 samples for COVID-19 infections) demonstrated a risk of arthrosclerosis in patients with influenza and COVID-19 infections, with an OR (odds ratio) = 0.45 ((95% CI): 0.25 to 0.64) and an OR (odds ratio) = 1.04 ((95% CI): 0.82 to 1.26), respectively. The present study provides new insights into the risk of atherosclerosis in patients infected with the COVID-19 and influenza viruses. Therefore, it seems necessary to consider different strategies for managing and eradicating viral infections among individuals.

Predictors of influenza severity among hospitalized adults with laboratory confirmed influenza: Analysis of nine influenza seasons from the Valencia region, Spain

Purpose

Influenza hospitalizations contribute substantially to healthcare disruption. We explored the impact of ageing, comorbidities and other risk factors to better understand associations with severe clinical outcomes in adults hospitalized with influenza.

Methods

We analysed multi‐season data from adults ≥18 years, hospitalized with laboratory‐confirmed influenza in Valencia, Spain. Severity was defined as intensive care unit (ICU) admission, assisted ventilation and/or death. Generalized estimating equations were used to estimate associations between risk factors and severity. Rate of hospital discharge was analysed with a cumulative incidence function.

Results

Only 26% of influenza patients had their primary discharge diagnosis coded as influenza. Comorbidities were associated with severity among adults aged 50–79 years, with the highest odds ratio (OR) in patients with ≥3 comorbidities aged 50–64 years (OR = 6.7; 95% CI: 1.0–44.6). Morbid obesity and functional dependencies were also identified risk factors (ORs varying from 3 to 5 depending on age). The presence of increasing numbers of comorbidities was associated with prolonged hospital stay.

Conclusions

Influenza clinical outcomes are aggravated by the presence of comorbidities and ageing. Increased awareness of influenza among hospitalized patients could prompt clinical and public health interventions to reduce associated burden.

Optimizing Immunization Strategies in Adult Patients With Chronic Liver Disease and Liver Transplant Recipients

Patients with chronic liver disease (CLD) and liver transplant recipients are at increased risk for infections from vaccine-preventable diseases. Gastroenterologists and hepatologists should assess patient immunization history, and necessary vaccinations should be given as soon as possible. Vaccines demonstrate superior immunogenicity when given earlier in the course of liver disease and prior to transplant. This article summarizes recommendations from the Advisory Committee on Immunization Practices for vaccinations in patients with CLD and liver transplant recipients, and includes a discussion of the influenza, herpes zoster, hepatitis A, hepatitis B, pneumococcal, human papillomavirus, and COVID-19 vaccines.

A Systematic Review of Influenza Epidemiology and Surveillance in the Eastern Mediterranean and North African Region

Seasonal influenza represents a huge health burden, resulting in significant mortality and morbidity. Following the 2009 H1N1 pandemic, focus has been directed on the burden of influenza globally. Country and regional disease burden estimates play important roles in helping inform decisions on national influenza intervention programmes. Despite improvements in influenza surveillance following the 2009 pandemic, many opportunities remain unexplored in the Eastern Mediterranean and North African (EMNA) region, which has a high prevalence of patients with chronic disease and thus a population at high risk of influenza complications. We conducted a systematic literature review of Embase, Medline, Scopus and the Cochrane Database of Systematic Reviews from 1 January 1998 to 31 January 2020 covering the EMNA region with the aim to describe the epidemiology of influenza in the region and assess the influenza epidemiological surveillance research landscape. Relevant data on study characteristics, population, clinical/virology characteristics and epidemiology were extracted and summarised descriptively. Of the 112 studies identified for inclusion, 90 were conducted in the Eastern Mediterranean region, 19 in North Africa and three across the EMNA region. Data were reported on 314,058 laboratory-confirmed influenza cases, 96 of which were derived from surveillance systems. Amongst the surveillance studies, the percentage of positive cases reported ranged from 1% to 100%. The predominantly identified influenza strain was strain A; H1N1 was the most prominent circulating subtype. Typing was performed in approximately 75% and subtyping in 50% of studies, respectively. Data on those considered most at risk for influenza complications were collected in 21% of studies, highlighting a regional gap for these data. Our review reveals existing gaps in regional estimates of influenza health and economic burden, hospitalisation rates and duration, and highlights the need for robust and high-quality epidemiology data to help inform public health interventions.

A TLR7 antagonist restricts interferon-dependent and -independent immunopathology in a mouse model of severe influenza

Cytokine-mediated immune-cell recruitment and inflammation contribute to protection in respiratory virus infection. However, uncontrolled inflammation and the "cytokine storm" are hallmarks of immunopathology in severe infection. Cytokine storm is a broad term for a phenomenon with diverse characteristics and drivers, depending on host genetics, age, and other factors. Taking advantage of the differential use of virus-sensing systems by different cell types, we test the hypothesis that specifically blocking TLR7-dependent, immune cell-produced cytokines reduces influenza-related immunopathology. In a mouse model of severe influenza characterized by a type I interferon (IFN-I)-driven cytokine storm, TLR7 antagonist treatment leaves epithelial antiviral responses unaltered but acts through pDCs and monocytes to reduce IFN-I and other cytokines in the lung, thus ameliorating inflammation and severity. Moreover, even in the absence of IFN-I signaling, TLR7 antagonism reduces inflammation and mortality driven by monocyte-produced chemoattractants and neutrophil recruitment into the infected lung. Hence, TLR7 antagonism reduces diverse types of cytokine storm in severe influenza.

Spotlight influenza: Laboratory-confirmed seasonal influenza in people with acute respiratory illness: a literature review and meta-analysis, WHO European Region, 2004 to 2017

BackgroundAcross the World Health Organization European Region, there are few estimates of the proportion of people seeking medical care for influenza-like illness or acute respiratory infections and who have laboratory-confirmed seasonal influenza infection.MethodsWe conducted a meta-analysis of data extracted from studies published between 2004 and 2017 and from sentinel data from the European surveillance system (TESSy) between 2004 and 2018. We pooled within-season estimates by influenza type/subtype, setting (outpatient (OP)/inpatient (IP)) and age group to estimate the proportion of people tested who have laboratory-confirmed and medically-attended seasonal influenza in Europe.ResultsIn the literature review, the pooled proportion for all influenza types was 33% (95% confidence interval (CI): 30-36), higher among OP 36% (95% CI: 33-40) than IP 24% (95% CI: 20-29). Pooled estimates for all influenza types by age group were: 0-17 years, 26% (22-31); 18-64 years, 41% (32-50); ≥ 65 years, 33% (27-40). From TESSy data, 33% (31-34) of OP and 24% (21-27) of IP were positive. The highest proportion of influenza A was in people aged 18-64 years (22%, 16-29). By subtype, A(H1N1)pdm09 was highest in 18-64 year-olds (16%, 11-21%) whereas A(H3N2) was highest in those ≥ 65 years (10%, 2-22). For influenza B, the highest proportion of infections was in those aged 18-64 years (15%, 9-24).ConclusionsLaboratory-confirmed influenza accounted for approximately one third of all acute respiratory infections for which medical care was sought during the influenza season.

Comparison between Patients Hospitalized with Influenza and COVID-19 at a Tertiary Care Center

BACKGROUND

Widespread reports suggest the characteristics and disease course of coronavirus disease 2019 (COVID-19) and influenza differ, yet detailed comparisons of their clinical manifestations are lacking.

OBJECTIVE

Comparison of the epidemiology and clinical characteristics of COVID-19 patients during the pandemic with those of influenza patients in previous influenza seasons at the same hospital DESIGN: Admission rates, clinical measurements, and clinical outcomes from confirmed COVID-19 cases between March 1 and April 30, 2020, were compared with those from confirmed influenza cases in the previous five influenza seasons (8 months each) beginning September 1, 2014.

SETTING

Large tertiary care teaching hospital in Boston, MA PARTICIPANTS: Laboratory-confirmed COVID-19 and influenza inpatients MEASUREMENTS: Patient demographics and medical history, mortality, incidence and duration of mechanical ventilation, incidences of vasopressor support and renal replacement therapy, and hospital and intensive care admissions.

RESULTS

Data was abstracted from medical records of 1052 influenza patients and 582 COVID-19 patients. An average of 210 hospital admissions for influenza occurred per 8-month season compared to 582 COVID-19 admissions over 2 months. The median weekly number of COVID-19 patients requiring mechanical ventilation was 17 (IQR: 4, 34) compared to a weekly median of 1 (IQR: 0, 2) influenza patient (p=0.001). COVID-19 patients were significantly more likely to require mechanical ventilation (31% vs 8%) and had significantly higher mortality (20% vs. 3%; p<0.001 for all). Relatively more COVID-19 patients on mechanical ventilation lacked pre-existing conditions compared with mechanically ventilated influenza patients (25% vs 4%, p<0.001). Pneumonia/ARDS secondary to the virus was the predominant cause of mechanical ventilation in COVID-19 patients (94%) as opposed to influenza (56%).

LIMITATION

This is a single-center study which could limit generalization.

CONCLUSION

COVID-19 resulted in more weekly hospitalizations, higher morbidity, and higher mortality than influenza at the same hospital.

Pre-existing conditions in Hispanics/Latinxs that are COVID-19 risk factors

Coronavirus disease 2019 (COVID-19) has exposed health care disparities in minority groups including Hispanics/Latinxs (HL). Studies of COVID-19 risk factors for HL have relied on county-level data. We investigated COVID-19 risk factors in HL using individual-level, electronic health records in a Los Angeles health system between March 9, 2020, and August 31, 2020. Of 9,287 HL tested for SARS-CoV-2, 562 were positive. HL constituted an increasing percentage of all COVID-19 positive individuals as disease severity escalated. Multiple risk factors identified in Non-Hispanic/Latinx whites (NHL-W), like renal disease, also conveyed risk in HL. Pre-existing nonrheumatic mitral valve disorder was a risk factor for HL hospitalization but not for NHL-W COVID-19 or HL influenza hospitalization, suggesting it may be a specific HL COVID-19 risk. Admission laboratory values also suggested that HL presented with a greater inflammatory response. COVID-19 risk factors for HL can help guide equitable government policies and identify at-risk populations.

Complicated hospitalization due to influenza: results from the Global Hospital Influenza Network for the 2017-2018 season

BACKGROUND

Since 2011, the Global Influenza Hospital Surveillance Network (GIHSN) has used active surveillance to prospectively collect epidemiological and virological data on patients hospitalized with influenza virus infection. Here, we describe influenza virus strain circulation in the GIHSN participant countries during 2017-2018 season and examine factors associated with complicated hospitalization among patients admitted with laboratory-confirmed influenza illness.

METHODS

The study enrolled patients who were hospitalized in a GIHSN hospital in the previous 48 h with acute respiratory symptoms and who had symptoms consistent with influenza within the 7 days before admission. Enrolled patients were tested by reverse transcription-polymerase chain reaction to confirm influenza virus infection. "Complicated hospitalization" was defined as a need for mechanical ventilation, admission to an intensive care unit, or in-hospital death. In each of four age strata (< 15, 15-< 50, 50-< 65, and ≥ 65 years), factors associated with complicated hospitalization in influenza-positive patients were identified by mixed effects logistic regression and those associated with length of hospital stay using a linear mixed-effects regression model.

RESULTS

The study included 12,803 hospitalized patients at 14 coordinating sites in 13 countries, of which 4306 (34%) tested positive for influenza. Influenza viruses B/Yamagata, A/H3N2, and A/H1N1pdm09 strains dominated and cocirculated, although the dominant strains varied between sites. Complicated hospitalization occurred in 10.6% of influenza-positive patients. Factors associated with complicated hospitalization in influenza-positive patients included chronic obstructive pulmonary disease (15-< 50 years and ≥ 65 years), diabetes (15-< 50 years), male sex (50-< 65 years), hospitalization during the last 12 months (50-< 65 years), and current smoking (≥65 years). Chronic obstructive pulmonary disease (50-< 65 years), other chronic conditions (15-< 50 years), influenza A (50-< 65 years), and hospitalization during the last 12 months (< 15 years) were associated with a longer hospital stay. The proportion of patients with complicated influenza did not differ between influenza A and B.

CONCLUSIONS

Complicated hospitalizations occurred in over 10% of patients hospitalized with influenza virus infection. Factors commonly associated with complicated or longer hospitalization differed by age group but commonly included chronic obstructive pulmonary disease, diabetes, and hospitalization during the last 12 months.

Encephalopathy and Encephalitis Associated with Cerebrospinal Fluid Cytokine Alterations and Coronavirus Disease, Atlanta, Georgia, USA, 2020

There are few detailed investigations of neurologic complications in severe acute respiratory syndrome coronavirus 2 infection. We describe 3 patients with laboratory-confirmed coronavirus disease who had encephalopathy and encephalitis develop. Neuroimaging showed nonenhancing unilateral, bilateral, and midline changes not readily attributable to vascular causes. All 3 patients had increased cerebrospinal fluid (CSF) levels of anti-S1 IgM. One patient who died also had increased levels of anti-envelope protein IgM. CSF analysis also showed markedly increased levels of interleukin (IL)-6, IL-8, and IL-10, but severe acute respiratory syndrome coronavirus 2 was not identified in any CSF sample. These changes provide evidence of CSF periinfectious/postinfectious inflammatory changes during coronavirus disease with neurologic complications.

Epidemiology and Clinical Outcomes of Hospitalizations for Acute Respiratory or Febrile Illness and Laboratory-Confirmed Influenza Among Pregnant Women During Six Influenza Seasons, 2010-2016

BACKGROUND

Pregnant women are at increased risk of seasonal influenza hospitalizations, but data about the epidemiology of severe influenza among pregnant women remain largely limited to pandemics.

METHODS

To describe the epidemiology of hospitalizations for acute respiratory infection or febrile illness (ARFI) and influenza-associated ARFI among pregnant women, administrative and electronic health record data were analyzed from retrospective cohorts of pregnant women hospitalized with ARFI who had testing for influenza viruses by reverse-transcription polymerase chain reaction (RT-PCR) in Australia, Canada, Israel, and the United States during 2010-2016.

RESULTS

Of 18 048 ARFI-coded hospitalizations, 1064 (6%) included RT-PCR testing for influenza viruses, 614 (58%) of which were influenza positive. Of 614 influenza-positive ARFI hospitalizations, 35% were in women with low socioeconomic status, 20% with underlying conditions, and 67% in their third trimesters. The median length of influenza-positive hospitalizations was 2 days (interquartile range, 1-4), 18% (95% confidence interval [CI], 15%-21%) resulted in delivery, 10% (95% CI, 8%-12%) included a pneumonia diagnosis, 5% (95% CI, 3%-6%) required intensive care, 2% (95% CI, 1%-3%) included a sepsis diagnosis, and <1% (95% CI, 0%-1%) resulted in respiratory failure.

CONCLUSIONS

Our findings characterize seasonal influenza hospitalizations among pregnant women and can inform assessments of the public health and economic impact of seasonal influenza on pregnant women.

Cost-effectiveness of quadrivalent versus trivalent influenza vaccine for elderly population in China

BACKGROUND

Influenza-associated excess death occurred most in the elderly. We aimed to assess the cost-effectiveness of quadrivalent influenza vaccine (QIV) versus trivalent influenza vaccine (TIV) for prevention of influenza infection among elderly population in China.

METHODS

A decision-analytic model was developed to compare 1-year clinical and economic outcomes of three influenza vaccination options (no vaccination, TIV, and QIV) in a hypothetical cohort of Chinese elderly aged 69 years. Outcome measures included cost, influenza infection rate, influenza-related mortality rate, quality-adjusted life-years (QALY) loss, and incremental cost-effectiveness ratio (ICER) from societal perspective. Sensitivity analyses were performed to examine the uncertainty of model inputs.

RESULTS

Base-case results showed no vaccination was dominated (more costly at higher QALY loss) by TIV and QIV. QIV was more costly (USD56.29 versus USD54.28) with lower influenza infection rate (0.608 versus 0.623), mortality rate (0.00199 versus 0.00204), and QALY loss (0.01213 versus 0.01243) than TIV. QIV was cost-effective compared to TIV with ICER of 6,700 USD/QALY below the willingness-to-pay threshold (29,580 USD/QALY). One-way sensitivity analysis found the cost-effectiveness of QIV was subject to the relative risk of vaccine effectiveness of QIV versus TIV, and TIV would be cost-effective if the relative risk was below 1.05. In 10,000 Monte Carlo simulations, the probabilities of QIV, TIV, and no vaccination to be cost-effective were 86.3%, 13.7%, and 0%, respectively.

CONCLUSION

QIV appears to be a cost-effective option compared to TIV and no influenza vaccination for elderly population in China.

Effectiveness of influenza vaccines in adults with chronic liver disease: a systematic review and meta-analysis

OBJECTIVES

Patients with liver disease frequently require hospitalisation with infection often the trigger. Influenza vaccination is an effective infection prevention strategy in healthy and elderly but is often perceived less beneficial in patients with liver disease. We investigated whether influenza vaccination triggered serological response and prevented hospitalisation and death in liver disease.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

MEDLINE, EMBASE, PubMed and CENTRAL up to January 2019.

ELIGIBILITY CRITERIA

Randomised or observational studies of the effects of influenza vaccine in adults with liver disease.

DATA EXTRACTION AND SYNTHESIS

Two reviewers screened studies, extracted data and assessed risk of bias and quality of evidence. Primary outcomes were all-cause hospitalisation and mortality. Secondary outcomes were cause-specific hospitalisation and mortality, and serological vaccine response. Random-effects meta-analysis was used to estimate pooled effects of vaccination.

RESULTS

We found 10 041 unique records, 286 were eligible for full-text review and 12 were included. Most patients had viral liver disease. All studies were of very low quality. Liver patients both with and without cirrhosis mounted an antibody response to influenza vaccination, and vaccination was associated with a reduction in risk of hospital admission from 205/1000 to 149/1000 (risk difference -0.06, 95% CI -0.07 to 0.04) in patients with viral liver disease. Vaccinated patients were 27% less likely to be admitted to hospital compared with unvaccinated patients (risk ratio 0.73, 95% CI 0.66 to 0.80). No effect against all-cause or cause-specific mortality or cause-specific hospitalisation was found.

CONCLUSIONS

The low quantity and quality of the evidence means that the protective vaccine effect may be uncertain. Considering the high risk of serious health outcomes from influenza infection in patients with liver disease and the safety and low cost of vaccination, overall, the potential benefits of seasonal vaccination both to patients and the healthcare systems are likely to outweigh the costs and risks associated with vaccination.

PROSPERO REGISTRATION NUMBER

CRD42017067277.

Comparative epidemiology of influenza B by lineage in intensive care unit-admitted patients with complications: A nationwide study in Taiwan, 2013-2017

BACKGROUND

We describe the relative proportions and epidemiological features of influenza B/Victoria and B/Yamagata, using data from nationwide surveillance systems.

METHODS

We collected respiratory samples from outpatients with influenza-like illness (ILI) and intensive care unit (ICU)-admitted patients with complications (pulmonary or neurological complications, myocarditis/pericarditis or invasive bacterial infection) for virus isolation and lineage typing. Demographics, epidemiological features, and vaccination history from ICU-admitted patients with complications were analyzed.

RESULTS

From July 2013-June 2017, 21% of 11517 influenza isolates were influenza B. B/Victoria was the predominant circulating strain in 2013-2014, accounted for 56% of all influenza B positive samples and B/Yamagata was predominant in 2014-2017 (82%, 69%, and 85%, respectively). Among all typed viruses, the proportion of B/Yamagata was higher among specimens from ICU-admitted patients with complications (77%, 154/199) than from ILI outpatients (66%, 276/418, p<0.005). Compared to B/Victoria, B/Yamagata infected ICU-admitted patients with complications were older, median age (71 vs. 59 years, p<0.05), had longer durations of hospitalization (15 vs. 7.5 days, p<0.05) and ICU stays (8.5 vs. 5.5 days, p<0.05).

CONCLUSIONS

Two lineages of influenza B viruses co-circulate annually in Taiwan. Among ICU-admitted patients with complications, B/Yamagata causes more severe illness than B/Victoria.

Influenza epidemiology and influenza vaccine effectiveness during the 2015-2016 season: results from the Global Influenza Hospital Surveillance Network

BACKGROUND

The Global Influenza Hospital Surveillance Network is an international platform whose primary objective is to study severe cases of influenza requiring hospitalization.

METHODS

During the 2015-2016 influenza season, 11 sites in the Global Influenza Hospital Surveillance Network in nine countries (Russian Federation, Czech Republic, Turkey, France, China, Spain, Mexico, India, and Brazil) participated in a prospective, active-surveillance, hospital-based epidemiological study. Influenza infection was confirmed by reverse transcription-polymerase chain reaction. Influenza vaccine effectiveness (IVE) against laboratory-confirmed influenza was estimated using a test-negative approach.

RESULTS

9882 patients with laboratory results were included of which 2415 (24.4%) were positive for influenza, including 1415 (14.3%) for A(H1N1)pdm09, 235 (2.4%) for A(H3N2), 180 (1.8%) for A not subtyped, 45 (0.5%) for B/Yamagata-lineage, 532 (5.4%) for B/Victoria-lineage, and 33 (0.3%) for B not subtyped. Of included admissions, 39% were < 5 years of age and 67% had no underlying conditions. The odds of being admitted with influenza were higher among pregnant than non-pregnant women (odds ratio, 2.82 [95% confidence interval (CI), 1.90 to 4.19]). Adjusted IVE against influenza-related hospitalization was 16.3% (95% CI, 0.4 to 29.7). Among patients targeted for influenza vaccination, adjusted IVE against hospital admission with influenza was 16.2% (95% CI, - 3.6 to 32.2) overall, 23.0% (95% CI, - 3.3 to 42.6) against A(H1N1)pdm09, and - 25.6% (95% CI, - 86.3 to 15.4) against B/Victoria lineage.

CONCLUSIONS

The 2015-2016 influenza season was dominated by A(H1N1)pdm09 and B/Victoria-lineage. Hospitalization with influenza often occurred in healthy and young individuals, and pregnant women were at increased risk of influenza-related hospitalization. Influenza vaccines provided low to moderate protection against hospitalization with influenza and no protection against the predominant circulating B lineage, highlighting the need for more effective and broader influenza vaccines.

Influenza epidemiology and influenza vaccine effectiveness during the 2016-2017 season in the Global Influenza Hospital Surveillance Network (GIHSN)

BACKGROUND

The Global Influenza Hospital Surveillance Network (GIHSN) aims to determine the burden of severe influenza disease and Influenza Vaccine Effectiveness (IVE). This is a prospective, active surveillance and hospital-based epidemiological study to collect epidemiological data in the GIHSN. In the 2016-2017 influenza season, 15 sites in 14 countries participated in the GIHSN, although the analyses could not be performed in 2 sites. A common core protocol was used in order to make results comparable. Here we present the results of the GIHSN 2016-2017 influenza season.

METHODS

A RT-PCR test was performed to all patients that accomplished the requirements detailed on a common core protocol. Patients admitted were included in the study after signing the informed consent, if they were residents, not institutionalised, not discharged in the previous 30 days from other hospitalisation with symptoms onset within the 7 days prior to admission. Patients 5 years old or more must also complied the Influenza-Like Illness definition. A test negative-design was implemented to perform IVE analysis. IVE was estimated using a logistic regression model, with the formula IVE = (1-aOR) × 100, where aOR is the adjusted Odds Ratio comparing cases and controls.

RESULTS

Among 21,967 screened patients, 10,140 (46.16%) were included, as they accomplished the inclusion criteria, and tested, and therefore 11,827 (53.84%) patients were excluded. Around 60% of all patients included with laboratory results were recruited at 3 sites. The predominant strain was A(H3N2), detected in 63.6% of the cases (1840 patients), followed by B/Victoria, in 21.3% of the cases (618 patients). There were 2895 influenza positive patients (28.6% of the included patients). A(H1N1)pdm09 strain was mainly found in Mexico. IVE could only be performed in 6 sites separately. Overall IVE was 27.24 (95% CI 15.62-37.27. Vaccination seemed to confer better protection against influenza B and in people 2-4 years, or 85 years old or older. The aOR for hospitalized and testing positive for influenza was 3.02 (95% CI 1.59-5.76) comparing pregnant with non-pregnant women.

CONCLUSIONS

Vaccination prevented around 1 in 4 hospitalisations with influenza. Sparse numbers didn't allow estimating IVE in all sites separately. Pregnancy was found a risk factor for influenza, having 3 times more risk of being admitted with influenza for pregnant women.

Post-pandemic influenza-associated mortality in Mexico

Influenza is a leading cause of respiratory tract infections worldwide and there is limited information on the impact of the influenza A(H1N1)pdm virus on mortality after the 2009 pandemic. Using national mortality register data through 1998-2015 in Mexico, influenza-associated mortality was estimated for respiratory, cardiovascular, and all-cause events. The proportion of influenza-associated respiratory and cardiovascular deaths among different age groups were compared. There were 8,853,986 death registries included for the 1998-2015 winter seasons, average influenza-associated respiratory, cardiovascular, and all-cause mortality rates were 5.2, 6.3, and 19.6 deaths/100,000 population, respectively. The largest number of respiratory influenza-associated deaths occurred in adults 60 years of age and older, followed by children <5 years of age; during the 2009 pandemic, 2011-2012, and 2013-2014 winter seasons there was a larger number of deaths in the 20-59 years old group. Influenza-associated mortality rates showed a continuous reduction in children <5 years of age. After the 2009 pandemic, influenza A(H1N1)pdm09 virus-associated mortality in Mexico showed a persistent change in the demographic pattern of the most severely affected population, particularly during the 2013-2014 season. Influenza associated-mortality has decreased in children <5 years of age and continue to be elevated in adults >60 years of age.

Circulation of influenza A and B in the Czech Republic from 2000-2001 to 2015-2016

Background

To improve national influenza vaccination recommendations, additional data on influenza A and B virus circulation are needed. Here, we describe the circulation of influenza A and B in the Czech Republic during 16 seasons.

Methods

This was a retrospective analysis of data collected from the 2000–2001 to 2015–2016 influenza seasons by the Czech Republic national influenza surveillance network. Influenza was confirmed and viral isolates subtyped by virological assays followed by antigen detection or by reverse transcriptase-polymerase chain reaction.

Results

Of 16,940 samples collected, 5144 (30.4%) were influenza-positive. Influenza A represented 78.6% of positive cases overall and accounted for more than 55.0% of all influenza cases in every season, except for 2005–2006 (6.0%). Both A/H1N1 and A/H3N2 were detected in most seasons, except for 2001–2002 and 2003–2004 (only A/H3N2), and 2007–2008 and 2009–2010 (only A/H1N1). Influenza B represented 21.4% of positive cases overall (range, 0.0–94.0% per season). Both influenza B lineages were detected in three seasons, a single B lineage in 11, and no B strain in two. For the 11 seasons where influenza B accounted for ≥20% of positive cases, the dominant lineage was Yamagata in six and Victoria in four. In the remaining season, the two lineages co-circulated. For two seasons (2005–2006 and 2007–2008), the B lineage in the trivalent influenza vaccine did not match the dominant circulating B lineage.

Conclusions

In the Czech Republic, during the 2000–2001 to 2015–2016 influenza seasons, influenza virus circulation varied considerably. Although influenza A accounted for the most cases in almost all seasons, influenza B made a substantial, sometimes dominant, contribution to influenza disease.

Excess Deaths Attributable to Influenza-Like Illness in the ESRD Population

BACKGROUND

Morbidity and mortality vary seasonally. Timing and severity of influenza seasons contribute to those patterns, especially among vulnerable populations such as patients with ESRD. However, the extent to which influenza-like illness (ILI), a syndrome comprising a range of potentially serious respiratory tract infections, contributes to mortality in patients with ESRD has not been quantified.

METHODS

We used data from the Centers for Disease Control and Prevention (CDC) Outpatient Influenza-like Illness Surveillance Network and Centers for Medicare and Medicaid Services ESRD death data from 2000 to 2013. After addressing the increasing trend in deaths due to the growing prevalent ESRD population, we calculated quarterly relative mortality compared with average third-quarter (summer) death counts. We used linear regression models to assess the relationship between ILI data and mortality, separately for quarters 4 and 1 for each influenza season, and model parameter estimates to predict seasonal mortality counts and calculate excess ILI-associated deaths.

RESULTS

An estimated 1% absolute increase in quarterly ILI was associated with a 1.5% increase in relative mortality for quarter 4 and a 2.0% increase for quarter 1. The average number of annual deaths potentially attributable to ILI was substantial, about 1100 deaths per year.

CONCLUSIONS

We found an association between community ILI activity and seasonal variation in all-cause mortality in patients with ESRD, with ILI likely contributing to >1000 deaths annually. Surveillance efforts, such as timely reporting to the CDC of ILI activity within dialysis units during influenza season, may help focus attention on high-risk periods for this vulnerable population.

Effect of vaccination, comorbidities and age on mortality and severe disease associated with influenza during the season 2016-2017 in a Spanish tertiary hospital

BACKGROUND

Identifying risk factors for complications or death associated with influenza remains crucial to target preventive interventions. Scores like the Charlson comorbidity index (CCI) may be of help. The aims of this study were to assess the effect of vaccination and comorbidities on severe influenza disease and influenza-related death among hospitalized patients during the season 2016/17; and to evaluate the validity of the CCI to predict death among these patients.

METHODS

Data from adult patients (≥18 years old) with influenza infection admitted to La Paz University Hospital (LPUH) were recorded during the 2016/17 epidemic. The effect of influenza vaccine to prevent severe influenza or death was evaluated using multivariate logistic regression models. The area under the curve of the CCI and the age-adjusted CCI were compared to assess the predictive effect on mortality.

RESULTS

A total of 342 adult patients with influenza infection were admitted, of which 83 developed severe influenza and 25 died during hospitalization. There were no differences between patients who survived and those who died concerning the CCI, but the age-adjusted CCI was higher in fatal cases (p-value=0.005). Influenza vaccine had no statistically significant effect on the risk of mortality (p-value=0.162) while age (OR: 1.12, p-value<0.001) and dementia (OR: 3.05, p-value=0.016) proved to be independent predictors for mortality. The seasonal vaccine was found to be protective for severe infection (OR: 0.54, p-value=0.019). The age-adjusted CCI was a better predictor of mortality than the crude CCI.

CONCLUSIONS

Age and dementia are significant independent risk factors for mortality associated with influenza among hospitalized patients. The age-adjusted CCI seems to be a better predictor of mortality than the crude CCI. Influenza vaccine has shown to be effective in preventing severe influenza in the season 2016/17 among hospitalized patients and should be promoted in population at risk.

Hormonal Regulation of Physiology, Innate Immunity and Antibody Response to H1N1 Influenza Virus Infection During Pregnancy

In 2009, the H1N1 swine flu pandemic highlighted the vulnerability of pregnant women to influenza viral infection. Pregnant women infected with influenza A virus were at increased risk of hospitalization and severe acute respiratory distress syndrome (ARDS), which is associated with high mortality, while their newborns had an increased risk of pre-term birth or low birth weight. Pregnant women have a unique immunological profile modulated by the sex hormones required to maintain pregnancy, namely progesterone and estrogens. The role of these hormones in coordinating maternal immunotolerance in uterine tissue and cellular subsets has been well researched; however, these hormones have wide-ranging effects outside the uterus in modulating the immune response to disease. In this review, we compile research findings in the clinic and in animal models that elaborate on the unique features of H1N1 influenza A viral pathogenesis during pregnancy, the crosstalk between innate immune signaling and hormonal regulation during pregnancy, and the role of pregnancy hormones in modulating cellular responses to influenza A viral infection at mid-gestation. We highlight the ways in which lung architecture and function is stressed by pregnancy, increasing baseline inflammation prior to infection. We demonstrate that infection disrupts progesterone production and upregulates inflammatory mediators, such as cyclooxygenase-2 (COX-2) and prostaglandins, resulting in pre-term labor and spontaneous abortions. Lastly, we profile the ways in which pregnancy alters innate and adaptive cellular immune responses to H1N1 influenza viral infection, and the ways in which these protect fetal development at the expense of effective long-term immune memory. Thus, we highlight advancements in the field of reproductive immunology in response to viral infection and illustrate how that knowledge might be used to develop more effective post-infection therapies and vaccination strategies.

Exploring the risk of severe outcomes and the role of seasonal influenza vaccination in pregnant women hospitalized with confirmed influenza, Spain, 2010/11-2015/16

Based on previous observations during pandemics and seasonal epidemics, pregnant women are considered at risk of developing severe influenza outcomes after influenza infection. With the aim of preventing severe influenza illness, the World Health Organization (WHO) includes pregnant women as a target group for seasonal influenza vaccination. However, influenza vaccine uptake during pregnancy remains low in many countries, including Spain. The objectives of this study were to increase the evidence of pregnancy as a risk factor for severe influenza illness and to study the potential role of seasonal influenza vaccination in the prevention of severe outcomes in infected pregnant women. Using information from the surveillance of Severe Hospitalized Confirmed Influenza Cases (SHCIC) in Spain, from seasons 2010/11 to 2015/16, we estimated that pregnant women in our study had a relative risk of hospitalization with severe influenza nearly 7.8 times higher than non-pregnant women of reproductive age. Only 5 out of 167 pregnant women with known vaccination status in our study had been vaccinated (3.6%). Such extremely low vaccination coverage only allowed obtaining crude estimates suggesting a protective effect of the vaccine against influenza complications (ICU admission or death). Our overall results support that pregnant women could benefit from seasonal influenza vaccination, in line with national and international recommendations.

Clinical characteristics and severity of influenza infections by virus type, subtype, and lineage: A systematic literature review

Aim

Studies carried out in the early 2000s found that the number of influenza‐associated hospitalizations and deaths was highest in seasons dominated by A(H3N2), suggesting that the clinical presentation and severity of influenza may differ across virus types, subtypes, and lineages. We aimed to review the studies that examined this hypothesis.

Method

We conducted a literature review of studies published until January 2017 that compared the clinical presentation, disease severity, and case‐fatality ratio of influenza patients infected with different virus types (A, B), subtypes (pre‐pandemic A(H1N1), A(H1N1)p, A(H3N2)), and lineages (Victoria, Yamagata).

Results

The literature search resulted in over 1700 entries: After applying in‐ and exclusion criteria, 47 studies were included in the literature review. Studies showed a wide diversity in setting and populations. Only a minority of studies provided results adjusted by patient's age and other potential confounders. There were very few differences in the clinical presentation of patients infected with different influenza viruses. We found weak evidence that the A(H1N1)p subtype in the post‐pandemic period was more often associated with secondary bacterial pneumonia, ICU admission, and death, than the other influenza virus (sub)types.

Conclusion

Contrary to what is commonly assumed, the causal virus subtype does not seem to be a major determinant of clinical presentation and severity of influenza illness. However, drawing conclusions was made difficult by the low comparability and methodological shortcomings of included studies, and more well‐designed studies are warranted.

A Snapshot of Influenza Surveillance, Vaccine Recommendations, and Vaccine Access, Drivers, and Barriers in Selected Middle Eastern and North African Countries

Objectives

Influenza is a vaccine-preventable acute respiratory viral infection that causes epidemics annually around the globe. A regional influenza stakeholder network (MENA-ISN) comprised of experts assessed the status of influenza prevention and control using a structured survey.

Methods

A survey questionnaire was used to obtain information from each participating country on surveillance system, the burden of disease, influenza vaccination programs, recommendations, funding and access for vaccine and vaccination, target rate, coverage rate monitoring, and drivers and barriers to influenza vaccination.

Results

Out of the 10 countries that participated, nine had an influenza surveillance system and vaccination policy, and seven had World Health Organization (WHO) accredited reference laboratory. Three countries had burden of disease data available and eight had a reimbursement vaccine policy. Influenza vaccine was available in five countries through the Ministry of Health whereas in others, pharmacies also dispensed for the private sector. In all countries, prescribers were physicians, and vaccinators, which could be physicians, nurses, and pharmacists. Eight countries had a set vaccination target rate and only three monitored the influenza coverage rates. Drivers and barriers of vaccination were similar in all countries.

Conclusions

Despite existing policies, influenza vaccination coverage remains far below the WHO recommendations. Increased awareness and effective implementation of policies with collaboration of stakeholders can help increase the rates to reach WHO targets.

Effectiveness of pneumococcal and influenza vaccines to prevent serious health complications in adults with chronic liver disease: a protocol for a systematic review

INTRODUCTION

In advanced chronic liver disease, diseases caused by common bacteria Streptococcus pneumoniae or influenza virus put people at an increased risk of serious health complications and death. The effectiveness of the available vaccines in reducing the risk of poor health outcomes, however, is less clear.

METHODS AND ANALYSIS

We will search Medline (Ovid), Embase (Ovid), PubMed and Cochrane Central Register of Controlled Trials for published reports on randomised controlled trials and observational studies on the effectiveness of pneumococcal and influenza vaccines in people with chronic liver disease. Two independent reviewers will screen the studies for eligibility, extract data and assess study quality and risk of bias. Random effects meta-analyses will be performed as appropriate.

ETHICS AND DISSEMINATION

Formal ethical approval is not required, as no primary data will be collected for this study. We will publish results of this study in relevant peer-reviewed medical journal or journals. Where possible, the study results will also be presented as posters or talks at relevant medical conferences and meetings.

PROSPERO REGISTRATION NUMBER

CRD42017067277.

Cost-effectiveness analysis of different seasonal influenza vaccines in the elderly Italian population

In the perspective of reaching at least 75% influenza vaccination coverage in the elderly and substantial budget constraints, Italian decision makers are facing important challenges in determining an optimal immunization strategy for this growing and particularly vulnerable population. Four different influenza vaccines are currently available for Italian older adults aged 65 years or above, namely trivalent inactivated vaccines (TIVs), MF59-adjuvanted TIV (MF59-TIV), intradermal TIV (ID-TIV) and quadrivalent inactivated vaccines (QIVs). The present study is the first to compare the cost-effectiveness profiles of virtually all possible public health strategies, including the aforementioned four vaccine formulations as well non-vaccination. For this purpose, a decision tree model was built ex novo; the analysis was conducted from the third-payer perspective in the timeframe of one year. All available vaccines were cost-effective compared with non-vaccination. However, MF59-TIV had the most favorable economic profile in the Italian elderly population. Indeed, compared with non-vaccination, it was deemed highly cost-effective with an incremental cost-effectiveness ratio (ICER) of €10,750 per quality-adjusted life year (QALY). The ICER was much lower (€4,527/QALY) when MF59-TIV was directly compared with TIV. ID-TIV and QIV were dominated by MF59-TIV as the former comparators were associated with greater total costs and lower health benefits. Both deterministic and probabilistic sensitivity analyses confirmed robustness of the base case results. From the economic perspective, MF59-TIV should be considered as a preferential choice for Italian older adults aged 65 years or above.

Infections and vasculitis

PURPOSE OF REVIEW

To review recent evidence for infection rates in patients with systemic vasculitides, the role of specific infectious agents in the pathogenesis of vasculitis and recent breakthroughs in the treatment of virus-associated vasculitides.

RECENT FINDINGS

In well designed recent studies, infections were found to be common during the first 6-12 months in patients with anti-neutrophil cytoplasmic antibodies (ANCA)-associated vasculitides (AAV) and giant cell arteritis (GCA) and to contribute significantly to increased mortality during this period. New therapeutic schemes with lower cyclophosphamide doses and shorter corticosteroid courses were associated with decreased infectious rates in elderly patients with AAV whereas a prednisone dose greater than 10 mg/day at the end of the first year were associated with increased infectious-related mortality in patients with GCA. Recently, a potential role for varicella zoster virus in GCA pathogenesis has been proposed but more data are needed in order to establish a causal relationship. Finally, preliminary data show excellent short-term efficacy and safety of the new, interferon-free, oral antiviral agents in the treatment of hepatitis C virus-associated cryoglobulinemic vasculitis.

SUMMARY

Infections continue to be one of the main causes of mortality in patients with systemic vasculitides, emphasizing the need for safer immunosuppressive therapies and appropriate prophylaxis.

Better knowledge and regular vaccination practices correlate well with higher seasonal influenza vaccine uptake in people at risk: Promising survey results from a university outpatient clinic

BACKGROUND

The knowledge, beliefs, opinions, and attitudes of patients and their relatives regarding seasonal influenza vaccination were evaluated.

METHODS

This descriptive study was undertaken in the outpatient clinics of Baskent University Hospital. There were 566 responders who completed a self-administered questionnaire.

RESULTS

The mean age of participants was 48.35 years, and 16.8% were ≥65 years. Of the responders, 21.7% were vaccinated this year, whereas 57.8% did not desire to get it. Vaccination rates were significantly higher among responders ≥65 years of age (56.4%), those having at least 1 chronic illness (46.5%), and those who were vaccinated regularly every year (22.2%). Half of the responders did not know that the vaccine was reimbursed for people at risk. The most common reason for refusing the influenza vaccine was not getting the flu frequently (51.2%). Fear of side effects, concerns about vaccine's effectiveness, and belief that vaccine causes the flu were other common reasons for not being vaccinated. Of the responders, 77% believed that getting official information or a recommendation from a physician would influence their decision about seasonal influenza vaccination.

CONCLUSIONS

People who are at risk or vaccinated regularly display a higher vaccine uptake and better knowledge of influenza and vaccination. The opinions and attitudes of this study population may assist in developing strategies for changing attitudes of the public toward influenza vaccination.

Epidemiology and Clinical Complication Patterns of Influenza A (H1N1 Virus) in Northern Saudi Arabia

The aim of the present study is to describe epidemiologic and clinical presentation, clinical complications and outcomes of patients diagnosed with influenza A infection (H1N1) during a one-year period. We retrospectively investigated 300 patients with influenza-like clinical presentation during the period January 2015 – January 2016 in King Khalid Hospital, Saudi Arabia. Fifty-four patients out of 300 (18%) were diagnosed with H1N1 virus infection; their age ranged from 7 months to 85 years, with a mean age of 25 years. Among them, 34 (63%) were males and 20 (37%) were females, with a M:F ratio of 1.70. The findings of this study show the great spread of influenza A outside the main holy cities of Saudi Arabia, and underline the absolute need for strict prevention strategies including vaccinations, public awareness and hygiene measures.

Influenza epidemiology and influenza vaccine effectiveness during the 2014-2015 season: annual report from the Global Influenza Hospital Surveillance Network

The Global Influenza Hospital Surveillance Network (GIHSN) has established a prospective, active surveillance, hospital-based epidemiological study to collect epidemiological and virological data for the Northern and Southern Hemispheres over several consecutive seasons. It focuses exclusively on severe cases of influenza requiring hospitalization. A standard protocol is shared between sites allowing comparison and pooling of results. During the 2014-2015 influenza season, the GIHSN included seven coordinating sites from six countries (St. Petersburg and Moscow, Russian Federation; Prague, Czech Republic; Istanbul, Turkey; Beijing, China; Valencia, Spain; and Rio de Janeiro, Brazil). Here, we present the detailed epidemiological and influenza vaccine effectiveness findings for the Northern Hemisphere 2014-2015 influenza season.