Clinical predictors of disease severity during the 2009–2010 A(HIN1) influenza virus pandemic in a paediatric population

2015 ◽  
Vol 143 (14) ◽  
pp. 2939-2949 ◽  
Author(s):  
M. N. GARCIA ◽  
D. C. PHILPOTT ◽  
K. O. MURRAY ◽  
A. ONTIVEROS ◽  
P. A. REVELL ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Disease Severity ◽  
Influenza A ◽  
Severe Disease ◽  
Paediatric Population ◽  
The United States ◽  
Clinical Predictors ◽  
Presenting Symptoms ◽  
Severe Influenza ◽  
Influenza A H1n1

SUMMARYA novel influenza virus emerged in the United States in spring 2009, rapidly becoming a global pandemic. Children were disproportionally affected by the novel influenza A(H1N1) pandemic virus [A(H1N1)pdm]. This retrospective electronic medical record review study aimed to identify clinical predictors of disease severity of influenza A(HIN1)pdm infection in paediatric patients. Disease severity was defined on an increasing three-level scale from non-hospitalized, hospitalized, and admitted to the intensive care unit (ICU). From April 2009 to June 2010, 696 children presented to Texas Children's Hospital's emergency department, 38% were hospitalized, and 17% were admitted to the ICU. Presenting symptoms associated with severe influenza were dyspnoea [odds ratio (OR) 5·82], tachycardia (OR 2·61) and fatigue (OR 1·96). Pre-existing health conditions associated with disease severity included seizure disorder (OR 4·71), obesity (OR 3·28), lung disease (OR 2·84), premature birth (OR 2·53), haematological disease (OR 2·22), and developmental delay (OR 2·20). According to model fitness tests, presenting symptoms were more likely to predict severe influenza than underlying medical conditions. However, both are important risk factors. Recognition of clinical characteristics associated with severe disease can be used for triaging case management of children during future influenza outbreaks.

Impact of influenza virus during pregnancy: from disease severity to vaccine efficacy

2020 ◽  
Vol 15 (7) ◽  
pp. 441-453
Author(s):  
Ana Vazquez-Pagan ◽  
Rebekah Honce ◽  
Stacey Schultz-Cherry
Keyword(s):  
Influenza Virus ◽  
Virus Infection ◽  
Immune Responses ◽  
Pregnant Women ◽  
Disease Severity ◽  
Influenza A ◽  
Antiviral Treatment ◽  
Influenza Virus Infection ◽  
Severe Influenza ◽  
The Impact

Pregnant women are among the individuals at the highest risk for severe influenza virus infection. Infection of the mother during pregnancy increases the probability of adverse fetal outcomes such as small for gestational age, preterm birth and fetal death. Animal models of syngeneic and allogeneic mating can recapitulate the increased disease severity observed in pregnant women and are used to define the mechanism(s) of that increased severity. This review focuses on influenza A virus pathogenesis, the unique immunological landscape during pregnancy, the impact of maternal influenza virus infection on the fetus and the immune responses at the maternal–fetal interface. Finally, we summarize the importance of immunization and antiviral treatment in this population and highlight issues that warrant further investigation.

scholarly journals Quantifying the mortality caused by the H1N1 influenza virus during the 2009 pandemic in Mexico

2014 ◽  
Vol 8 (06) ◽  
pp. 742-748 ◽  
Author(s):  
Eusebio Perez-Flores ◽  
Juan Carlos Izquierdo-Puente ◽  
Jose Juan Castillo-Perez ◽  
Gustavo Ramírez-Rosales ◽  
Israel Grijalva-Otero ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Cause Of Death ◽  
Influenza A ◽  
H1n1 Influenza ◽  
The United States ◽  
Study Data ◽  
Death Certificates ◽  
Influenza A H1n1 ◽  
Uniform Probability Distribution ◽  
Source Of Error

Introduction: The frequency and mortality of the pandemic caused by influenza A(H1N1)pdm09 might have been underestimated, especially in developing countries. This study was designed to quantify the possible underestimation of pandemic influenza mortality and evaluate the concordance between the data reported for A(H1N1)pdm09 mortality and the causes of death reported during the pandemic period of April 2009 to February 2010. Methodology: The death certificates of 754 confirmed cases of A(H1N1)pdm09 infection were included in the study. Data was analyzed using the United States Centers for Disease Control and Prevention’s statistical model accounts for the variability in the proportion at each step using the Monte Carlo probabilistic model sampled from a uniform probability distribution. Results: A total of 1,969 deaths were estimated, with an estimated lethality of 5.53 per 100,000 (range, 3.5-8.76 per 100,000) in contrast with the 754 deaths and a lethality of 1.98 per 100,000 infected patients officially reported. In 631 of 754 (83.7%) death certificates from A(H1N1)pdm09 influenza-positive patients, influenza was not mentioned as a cause of death. Conclusions: It is possible that the mortality of the pandemic was three times higher than officially reported in Mexico. One source of error that could explain this underestimation is in the completion of death certificates, because in > 80% of confirmed cases of infection with influenza virus, it was not reported as the cause of death.

scholarly journals Pathogenesis of Pandemic Influenza A (H1N1) and Triple-Reassortant Swine Influenza A (H1) Viruses in Mice

2010 ◽  
Vol 84 (9) ◽  
pp. 4194-4203 ◽  
Author(s):  
Jessica A. Belser ◽  
Debra A. Wadford ◽  
Claudia Pappas ◽  
Kortney M. Gustin ◽  
Taronna R. Maines ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
H1n1 Virus ◽  
Swine Influenza Virus ◽  
Swine Influenza ◽  
The United States ◽  
Chemokine Production ◽  
Highly Pathogenic ◽  
Influenza A H1n1 ◽  
2009 H1n1

ABSTRACT The pandemic H1N1 virus of 2009 (2009 H1N1) continues to cause illness worldwide, primarily in younger age groups. To better understand the pathogenesis of these viruses in mammals, we used a mouse model to evaluate the relative virulence of selected 2009 H1N1 viruses and compared them to a representative human triple-reassortant swine influenza virus that has circulated in pigs in the United States for over a decade preceding the current pandemic. Additional comparisons were made with the reconstructed 1918 virus, a 1976 H1N1 swine influenza virus, and a highly pathogenic H5N1 virus. Mice were inoculated intranasally with each virus and monitored for morbidity, mortality, viral replication, hemostatic parameters, cytokine production, and lung histology. All 2009 H1N1 viruses replicated efficiently in the lungs of mice and possessed a high degree of infectivity but did not cause lethal disease or exhibit extrapulmonary virus spread. Transient weight loss, lymphopenia, and proinflammatory cytokine and chemokine production were present following 2009 H1N1 virus infection, but these levels were generally muted compared with a triple-reassortant swine virus and the 1918 virus. 2009 H1N1 viruses isolated from fatal cases did not demonstrate enhanced virulence in this model compared with isolates from mild human cases. Histologically, infection with the 2009 viruses resulted in lesions in the lung varying from mild to moderate bronchiolitis with occasional necrosis of bronchiolar epithelium and mild to moderate peribronchiolar alveolitis. Taken together, these studies demonstrate that the 2009 H1N1 viruses exhibited mild to moderate virulence in mice compared with highly pathogenic viruses.

scholarly journals TNFA and IL10 Polymorphisms and IL-6 and IL-10 Levels Influence Disease Severity in Influenza A(H1N1)pdm09 Virus Infected Patients

Genes ◽  
2021 ◽  
Vol 12 (12) ◽  
pp. 1914
Author(s):  
Kalichamy Alagarasu ◽  
Himanshu Kaushal ◽  
Pooja Shinde ◽  
Mahadeo Kakade ◽  
Urmila Chaudhary ◽  
...  
Keyword(s):  
Disease Severity ◽  
Influenza A ◽  
Severe Disease ◽  
Fatal Outcome ◽  
Nucleotide Polymorphisms ◽  
Single Nucleotide ◽  
Mild Disease ◽  
Pdm09 Virus ◽  
Potential Biomarker ◽  
Influenza A H1n1

Cytokines are key modulators of immune response, and dysregulated production of proinflammatory and anti-inflammatory cytokines contributes to the pathogenesis of influenza A(H1N1)pdm09 virus infection. Cytokine production is impacted by single nucleotide polymorphisms (SNPs) in the genes coding for them. In the present study, SNPs in the IL6, TNFA, IFNG, IL17A, IL10, and TGFB were investigated for their association with disease severity and fatality in influenza A(H1N1)pdm09-affected patients with mild disease (n = 293) and severe disease (n = 86). Among those with severe disease, 41 patients had fatal outcomes. In a subset of the patients, levels of IL-2, IL-4, IL-6, IL-10, TNF, IFN-γ, and IL-17 were assayed in the plasma for their association with severe disease. The frequency of TNFA rs1800629 G/A allele was significantly higher in severe cases and survived severe cases group compared to that of those with mild infection (OR with 95% for mild vs. severe cases 2.95 (1.52–5.73); mild vs. survived severe cases 4.02 (1.84–8.82)). IL10 rs1800896-rs1800872 G-C haplotype was significantly lower (OR with 95% 0.34 (0.12–0.95)), while IL10 rs1800896-rs1800872 G-A haplotype was significantly higher (OR with 95% 12.11 (2.23–76.96)) in fatal cases group compared to that of the mild group. IL-6 and IL-10 levels were significantly higher in fatal cases compared to that of survived severe cases. IL-6 levels had greater discriminatory power than IL-10 to predict progression to fatal outcome in influenza A(H1N1)pdm09 virus-infected patients. To conclude, the present study reports the association of TNFA and IL10 SNPs with severe disease in Influenza A(H1N1)pdm09 virus-infected subjects. Furthermore, IL-6 levels can be a potential biomarker for predicting fatal outcomes in Influenza A(H1N1)pdm09 virus infected subjects.

scholarly journals Association between plasma glycocalyx component levels and poor prognosis in severe influenza type A (H1N1)

2022 ◽  
Vol 12 (1) ◽  
Author(s):  
Xiao Huang ◽  
Feng Lu ◽  
Huanhuan Tian ◽  
Haoran Hu ◽  
Fangyu Ning ◽  
...  
Keyword(s):  
Heparan Sulfate ◽  
Disease Severity ◽  
Plasma Levels ◽  
Influenza A ◽  
Strong Association ◽  
H1n1 Influenza ◽  
Endothelial Glycocalyx ◽  
Inflammatory Factors ◽  
Severe Influenza ◽  
Influenza A H1n1

AbstractInfluenza A virus infection causes a series of diseases, but the factors associated with disease severity are not fully understood. Disruption of the endothelial glycocalyx contributes to acute lung injury in sepsis, but has not been well studied in H1N1 influenza. We aim to determine whether the plasma glycocalyx components levels are predictive of disease severity in H1N1 influenza. This prospective observational study included 53 patients with influenza A (H1N1) during the influenza season, and 30 healthy controls in our hospital. Patients were grouped by severity and survival. We collected clinical data and blood samples at admission. Inflammatory factors (tumor necrosis factor-α, interleukin-6, interleukin-10) and endothelial glycocalyx components (syndecan-1, hyaluronan, heparan sulfate) were measured. The plasma levels of syndecan-1, hyaluronan, and heparan sulfate were significantly higher in patients with severe influenza A (H1N1) than in mild cases. Syndecan-1 and hyaluronan were positively correlated with disease severity, which was indicated by the APACHE II and SOFA scores and lactate levels, and negatively correlated with albumin levels. At a cutoff point ≥ 173.9 ng/mL, syndecan-1 had a 81.3% sensitivity and 70.3% specificity for predicting of 28-day mortality. Kaplan–Meier analysis demonstrated a strong association between syndecan-1 levels and 28-day mortality (log-rank 11.04, P = 0.001). Elevated plasma levels of syndecan-1 has a potential role in systemic organ dysfunction and may be indicative of disease severity in patients with influenza A (H1N1).

scholarly journals Comparison of the Outcomes of Individuals With Medically Attended Influenza A and B Virus Infections Enrolled in 2 International Cohort Studies Over a 6-Year Period: 2009–2015

2017 ◽  
Vol 4 (4) ◽  
Author(s):  
Dominic E Dwyer ◽  
Ruth Lynfield ◽  
Marcelo H Losso ◽  
Richard T Davey ◽  
Alessandro Cozzi-Lepri ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Severe Disease ◽  
Hospitalized Patients ◽  
Sensitivity Analyses ◽  
Influenza B ◽  
Virus Infections ◽  
Influenza A H1n1 ◽  
B Virus

Abstract Background Outcome data from prospective follow-up studies comparing infections with different influenza virus types/subtypes are limited. Methods Demographic, clinical characteristics and follow-up outcomes for adults with laboratory-confirmed influenza A(H1N1)pdm09, A(H3N2), or B virus infections were compared in 2 prospective cohorts enrolled globally from 2009 through 2015. Logistic regression was used to compare outcomes among influenza virus type/subtypes. Results Of 3952 outpatients, 1290 (32.6%) had A(H1N1)pdm09 virus infection, 1857 (47.0%) had A(H3N2), and 805 (20.4%) had influenza B. Of 1398 inpatients, 641 (45.8%) had A(H1N1)pdm09, 532 (38.1%) had A(H3N2), and 225 (16.1%) had influenza B. Outpatients with A(H1N1)pdm09 were younger with fewer comorbidities and were more likely to be hospitalized during the 14-day follow-up (3.3%) than influenza B (2.2%) or A(H3N2) (0.7%; P < .0001). Hospitalized patients with A(H1N1)pdm09 (20.3%) were more likely to be enrolled from intensive care units (ICUs) than those with A(H3N2) (11.3%) or B (9.8%; P < .0001). However, 60-day follow-up of discharged inpatients showed no difference in disease progression (P = .32) or all-cause mortality (P = .30) among influenza types/subtypes. These findings were consistent after covariate adjustment, in sensitivity analyses, and for subgroups defined by age, enrollment location, and comorbidities. Conclusions Outpatients infected with influenza A(H1N1)pdm09 or influenza B were more likely to be hospitalized than those with A(H3N2). Hospitalized patients infected with A(H1N1)pdm09 were younger and more likely to have severe disease at study entry (measured by ICU enrollment), but did not have worse 60-day outcomes.

scholarly journals Comparable Disease Severity by Influenza Virus Subtype in the Acute Respiratory Infection Consortium Natural History Study

2020 ◽  
Vol 185 (7-8) ◽  
pp. e1008-e1015
Author(s):  
Christina Schofield ◽  
Rhonda E Colombo ◽  
Stephanie A Richard ◽  
Wei-Ju Chen ◽  
Mary P Fairchok ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Disease Severity ◽  
Department Of Defense ◽  
Symptom Severity ◽  
Influenza A ◽  
H1n1 Influenza ◽  
Influenza B ◽  
Prevention Measures ◽  
Severity Scores ◽  
Influenza A H1n1

Abstract Introduction Since the influenza A/H1N1 pandemic of 2009 to 2010, numerous studies have described the clinical course and outcome of the different subtypes of influenza (A/H1N1, A/H3N2, and B). A recent systematic literature review concluded that there were no appreciable differences in either clinical presentation or disease severity among these subtypes, but study parameters limit the applicability of these results to military populations. We sought to evaluate differences in disease severity among influenza subtypes in a cohort of healthy, primarily outpatient adult U.S. Department of Defense beneficiaries. Materials and Methods From 2009 to 2014, we enrolled otherwise healthy adults age 18 to 65 years with influenza-like illness in an observational cohort study based in 5 U.S. military medical centers. Serial nasopharyngeal swabs were collected for determination of etiology and viral shedding by polymerase chain reaction. The presence and severity of symptoms was assessed by interview and patient diary. Results Over a 5-year period, a total of 157 adults with laboratory-confirmed influenza and influenza subtype were enrolled. Of these, 69 (44%) were positive for influenza A(H1N1), 69 (44%) for influenza A(H3N2), and 19 (12%) for influenza B. About 61% were male, 64% were active duty military personnel, and 72% had received influenza vaccine in the past 8 months. Almost 10% were hospitalized with influenza. Seasonal influenza virus distribution among enrollees mirrored that of nationwide trends each year of study. Individuals with A/H1N1 had upper respiratory composite scores that were lower than those with A/H3N2. Multivariate models indicated that individuals with A(H1N1) and B had increased lower respiratory symptom scores when compared to influenza A(H3N2) (A[H1N1]: 1.51 [95% CI 0.47, 2.55]; B: 1.46 [95% CI 0.09, 2.83]), whereas no other differences in symptom severity scores among influenza A(H1N1), influenza A(H3N2), and influenza B infection were observed. Overall, influenza season (maximum in 2012–2013 season) and female sex of the participant were found to be associated with increased influenza symptom severity. Conclusions Our study of influenza in a cohort of otherwise healthy, outpatient adult Department of Defense beneficiaries over 5 influenza seasons revealed few differences between influenza A(H1N1), influenza A(H3N2), and influenza B infection with respect to self-reported disease severity or clinical outcomes. This study highlights the importance of routine, active, and laboratory-based surveillance to monitor ongoing trends and severity of influenza in various populations to inform prevention measures.

scholarly journals Interaction Among Influenza Viruses A/H1N1, A/H3N2, and B in Japan

2019 ◽  
Vol 16 (21) ◽  
pp. 4179 ◽  
Author(s):  
Ayako Suzuki ◽  
Kenji Mizumoto ◽  
Andrei R. Akhmetzhanov ◽  
Hiroshi Nishiura
Keyword(s):  
Influenza Virus ◽  
Virus Type ◽  
Influenza A ◽  
Seasonal Influenza ◽  
Winter Season ◽  
The United States ◽  
Influenza Viruses ◽  
Statistical Correlations ◽  
Epidemic Size ◽  
Influenza A H1n1

Seasonal influenza epidemics occur each winter season in temperate zones, involving up to 650,000 deaths each year globally. A published study demonstrated that the circulation of one influenza virus type during early influenza season in the United States interferes with the activity of other influenza virus types. However, this finding has yet to be validated in other settings. In the present work, we investigated the interaction among seasonal influenza viruses (A/H1N1, A/H3N2 and B) in Japan. Sentinel and virus surveillance data were used to estimate the type-specific incidence from 2010 to 2019, and statistical correlations among the type-specific incidence were investigated. We identified significant negative correlations between incidence of the dominant virus and the complementary incidence. When correlation was identified during the course of an epidemic, a linear regression model accurately predicted the epidemic size of a particular virus type before the epidemic peak. The peak of influenza type B took place later in the season than that of influenza A, although the epidemic peaks of influenza A/H1N1 and A/H3N2 nearly coincided. Given the interaction among different influenza viruses, underlying mechanisms including age and spatial dependence should be explored in future.

scholarly journals Severe Influenza in 33 US Hospitals, 2013–2014: Complications and Risk Factors for Death in 507 Patients

2015 ◽  
Vol 36 (11) ◽  
pp. 1251-1260 ◽  
Author(s):  
Nirav S. Shah ◽  
Jared A. Greenberg ◽  
Moira C. McNulty ◽  
Kevin S. Gregg ◽  
James Riddell ◽  
...  
Keyword(s):  
Risk Factors ◽  
Intensive Care Unit ◽  
Intensive Care ◽  
Influenza A ◽  
Influenza Season ◽  
Influenza Infection ◽  
Patient Characteristics ◽  
The United States ◽  
Severe Influenza ◽  
Influenza A H1n1

BACKGROUNDInfluenza A (H1N1) pdm09 became the predominant circulating strain in the United States during the 2013–2014 influenza season. Little is known about the epidemiology of severe influenza during this season.METHODSA retrospective cohort study of severely ill patients with influenza infection in intensive care units in 33 US hospitals from September 1, 2013, through April 1, 2014, was conducted to determine risk factors for mortality present on intensive care unit admission and to describe patient characteristics, spectrum of disease, management, and outcomes.RESULTSA total of 444 adults and 63 children were admitted to an intensive care unit in a study hospital; 93 adults (20.9%) and 4 children (6.3%) died. By logistic regression analysis, the following factors were significantly associated with mortality among adult patients: older age (>65 years, odds ratio, 3.1 [95% CI, 1.4–6.9], P=.006 and 50–64 years, 2.5 [1.3–4.9], P=.007; reference age 18–49 years), male sex (1.9 [1.1–3.3], P=.031), history of malignant tumor with chemotherapy administered within the prior 6 months (12.1 [3.9–37.0], P<.001), and a higher Sequential Organ Failure Assessment score (for each increase by 1 in score, 1.3 [1.2–1.4], P<.001).CONCLUSIONRisk factors for death among US patients with severe influenza during the 2013–2014 season, when influenza A (H1N1) pdm09 was the predominant circulating strain type, shifted in the first postpandemic season in which it predominated toward those of a more typical epidemic influenza season.Infect. Control Hosp. Epidemiol. 2015;36(11):1251–1260

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