scholarly journals Direct and Indirect Protection with Pediatric Quadrivalent Live-Attenuated Influenza Vaccination in Europe Estimated by a Dynamic Transmission Model

10.36469/9801 ◽  
2017 ◽  
Vol 5 (1) ◽  
pp. 89-108 ◽  
Author(s):  
Laetitia Gerlier ◽  
Judith Hackett ◽  
Richard Lawson ◽  
Sofia Dos Santos Mendes ◽  
Catherine Weil-Olivier ◽  
...  
Keyword(s):  
Vaccination Coverage ◽  
Influenza A ◽  
Sensitivity Analyses ◽  
Transmission Model ◽  
Base Case ◽  
Reference Scenario ◽  
Natural Immunity ◽  
Healthy Children ◽  
Population Average ◽  
Indirect Protection

Objectives: To estimate the public health impact of annual vaccination of children with a quadrivalent live-attenuated influenza vaccine (QLAIV) across Europe. Methods: A deterministic, age-structured, dynamic model was used to simulate influenza transmission across 14 European countries, comparing current vaccination coverage using a quadrivalent inactivated vaccine (QIV) to a scenario whereby vaccination coverage was extended to 50% of 2–17 year-old children, using QLAIV. Differential equations described demographic changes, exposure to infectious individuals, recovery and immunity dynamics. For each country, the basic reproduction number (R0) was calibrated to published influenza incidence statistics. Assumed vaccine efficacy for children was 80% (QLAIV) and 59% (QIV). Symptomatic cases cumulated over 10 years were calculated per 100 000 person-years. One-way sensitivity analyses were conducted on QLAIV efficacy in 7–17 year-olds (59% instead of 80%), durations of natural (±3 years; base case: 6, 12 years for influenza A, B respectively) and QLAIV vaccine-induced immunity (100% immunity loss after 1 season; base case: 30%), and R0 (+/-10% around all-year average value). Results: Across countries, annual QLAIV vaccination additionally prevents 1366–3604 symptomatic cases per 100 000 population (average 2495 /100 000, ie, a reduction of 47.6% of the cases which occur in the reference scenario with QIV vaccination only). Among children (2–17 years), QLAIV prevents 551–1555 cases per 100 000 population (average 990 /100 000, ie, 67.2% of current cases). Among adults, QLAIV indirectly prevents 726-2047 cases per 100 000 population (average 1466 /100 000, ie, 40.0% of current cases). The most impactful drivers of total protection were duration of natural immunity against influenza A, R0 and QLAIV immunity duration and efficacy. In all evaluated scenarios, there was a large direct and even larger indirect protection compared with the reference scenario. Conclusions: The model highlights direct and indirect protection benefits when vaccinating healthy children with QLAIV in Europe, across a range of demographic structures, contact patterns and vaccination coverage rates.

scholarly journals Identifying silent COVID-19 infections among children is critical for controlling the pandemic

2021 ◽  
Author(s):  
Seyed M. Moghadas ◽  
Meagan C. Fitzpatrick ◽  
Affan Shoukat ◽  
Kevin Zhang ◽  
Alison P. Galvani
Keyword(s):  
Vaccination Coverage ◽  
Vaccine Efficacy ◽  
The United States ◽  
Sensitivity Analyses ◽  
Transmission Model ◽  
Base Case ◽  
Age Group ◽  
One Year ◽  
The Impact ◽  
Targeted Approach

Importance: A significant proportion of COVID-19 transmission occurs silently during the pre-symptomatic and asymptomatic stages of infection. Children, while being important drivers of silent transmission, are not included in COVID-19 vaccination campaigns given their exclusion from clinical trials thus far. Objective: To investigate the impact of a targeted approach to identifying silent infections among children as a proxy for their vaccination. Design: This study used an age-structured disease transmission model to simulate the synergistic impact of interventions in reducing attack rates over the course of one year. Setting: A synthetic population representative of the demographics of the United States (US). Participants: Six age groups of 0-4, 5-10, 11-18, 19-49, 50-64, 65+ years old, stratified for their population size based on US census data. Exposures: Vaccination of adults, self-isolation of all symptomatic cases within 24 hours of symptom onset, and detection of silent infections. Main Outcomes and Measures: Vaccination of adults was implemented to reach a 40% coverage over the course of one year with a vaccine efficacy of 95% against symptomatic and severe COVID-19. Without vaccination of children, we determined the proportion and speed that would be required for identifying silent infections among this age group to suppress future attack rates below 5%. Results: A targeted approach that identifies 20.6% and 28.6% of silent infections among children within 2 or 3 days post-infection, respectively, would be required to bring attack rates under 5% with vaccination of adults. If silent infections among children remained undetected, achieving the same attack rates would require an unrealistically high vaccination coverage (at least 82%) of this age group, in addition to the base-case 40% vaccination coverage of adults. The results were robust in sensitivity analyses with respect to vaccine efficacy against infection and reduced susceptibility of children to infection. Conclusions and Relevance: In the absence of vaccine availability for children, a targeted approach to rapid identification of silent COVID-19 infections in this age group can significantly mitigate disease burden. Without measures to interrupt transmission chains from silent infections, vaccination of adults is unlikely to contain the outbreaks in the near term.

scholarly journals The potential health and economic value of SARS-CoV-2 vaccination alongside physical distancing in the UK: transmission model-based future scenario analysis and economic evaluation

2020 ◽  
Author(s):  
Frank Sandmann ◽  
Nicholas Davies ◽  
Anna Vassall ◽  
W John Edmunds ◽  
Mark Jit ◽  
...  
Keyword(s):  
National Economy ◽  
Economic Value ◽  
Vaccine Effectiveness ◽  
Transmission Model ◽  
Base Case ◽  
Natural Immunity ◽  
Potential Health ◽  
Monetary Value ◽  
Life Years ◽  
The Uk

Background In response to the coronavirus disease 2019 (COVID-19), the UK adopted mandatory physical distancing measures in March 2020. Vaccines against the newly emerged severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) may become available as early as late 2020. We explored the health and economic value of introducing SARS-CoV-2 immunisation alongside physical distancing scenarios in the UK. Methods We used an age-structured dynamic-transmission and economic model to explore different scenarios of immunisation programmes over ten years. Assuming vaccines are effective in 5-64 year olds, we compared vaccinating 90% of individuals in this age group to no vaccination. We assumed either vaccine effectiveness of 25% and 1-year protection and 90% re-vaccinated annually, or 75% vaccine effectiveness and 10-year protection and 10% re-vaccinated annually. Natural immunity was assumed to last 45 weeks in the base case. We also explored the additional impact of physical distancing. We considered benefits from disease prevented in terms of quality-adjusted life-years (QALYs), and costs to the healthcare payer versus the national economy. We discounted at 3.5% annually and monetised health impact at 20,000 per QALY to obtain the net monetary value, which we explored in sensitivity analyses. Findings Without vaccination and physical distancing, we estimated 147.9 million COVID-19 cases (95% uncertainty interval: 48.5 million, 198.7 million) and 2.8 million (770,000, 4.2 million) deaths in the UK over ten years. Vaccination with 75% vaccine effectiveness and 10-year protection may stop community transmission entirely for several years, whereas SARS-CoV-2 becomes endemic without highly effective vaccines. Introducing vaccination compared to no vaccination leads to economic gains (positive net monetary value) of 0.37 billion to +1.33 billion across all physical distancing and vaccine effectiveness scenarios from the healthcare perspective, but net monetary values of physical distancing scenarios may be negative from societal perspective if the daily national economy losses are persistent and large. Interpretation Our model findings highlight the substantial health and economic value of introducing SARS-CoV-2 vaccination. Given uncertainty around both characteristics of the eventually licensed vaccines and long-term COVID-19 epidemiology, our study provides early insights about possible future scenarios in a post-vaccination era from an economic and epidemiological perspective.

scholarly journals Predicting the Impact of Typhoid Conjugate Vaccines on Antimicrobial Resistance

2019 ◽  
Vol 68 (Supplement_2) ◽  
pp. S96-S104 ◽  
Author(s):  
Samantha Kaufhold ◽  
Reza Yaesoubi ◽  
Virginia E Pitzer
Keyword(s):  
Vaccination Coverage ◽  
Selective Pressure ◽  
Sensitivity Analyses ◽  
Relative Fitness ◽  
Base Case ◽  
Model Parameters ◽  
Case Scenario ◽  
Conjugate Vaccines ◽  
Model Predictions ◽  
The Impact

Abstract Background Empiric prescribing of antimicrobials in typhoid-endemic settings has increased selective pressure on the development of antimicrobial-resistant Salmonella enterica serovar Typhi. The introduction of typhoid conjugate vaccines (TCVs) in these settings may relieve this selective pressure, thereby reducing resistant infections and improving health outcomes. Methods A deterministic transmission dynamic model was developed to simulate the impact of TCVs on the number and proportion of antimicrobial-resistant typhoid infections and chronic carriers. One-way sensitivity analyses were performed to ascertain particularly impactful model parameters influencing the proportion of antimicrobial-resistant infections and the proportion of cases averted over 10 years. Results The model simulations suggested that increasing vaccination coverage would decrease the total number of antimicrobial-resistant typhoid infections but not affect the proportion of cases that were antimicrobial resistant. In the base-case scenario with 80% vaccination coverage, 35% of all typhoid infections were antimicrobial resistant, and 44% of the total cases were averted over 10 years by vaccination. Vaccination also decreased both the total number and proportion of chronic carriers of antimicrobial-resistant infections. The prevalence of chronic carriers, recovery rates from infection, and relative fitness of resistant strains were identified as crucially important parameters. Conclusions Model predictions for the proportion of antimicrobial resistant infections and number of cases averted depended strongly on the relative fitness of the resistant strain(s), prevalence of chronic carriers, and rates of recovery without treatment. Further elucidation of these parameter values in real-world typhoid-endemic settings will improve model predictions and assist in targeting future vaccination campaigns and treatment strategies.

scholarly journals Influenza-Associated Pediatric Deaths in the United States, 2010–2015

2017 ◽  
Vol 9 (1) ◽  
Author(s):  
Mei Shang ◽  
Lenee Blanton ◽  
Sonja Olsen ◽  
Alicia Fry ◽  
Lynnette Brammer
Keyword(s):  
United States ◽  
Vaccination Coverage ◽  
Influenza A ◽  
The United States ◽  
H3n2 Virus ◽  
Severe Illness ◽  
Influenza B Virus ◽  
Influenza B ◽  
Healthy Children ◽  
B Virus

ObjectiveTo characterize and describe influenza-associated pediatric deathsin the United States over five influenza seasons, 2010–11 through2014–15.IntroductionCommunity influenza infection rates are highest among children.In children, influenza can cause severe illness and complicationsincluding, respiratory failure and death. Annual influenza vaccinationis recommended for all persons aged≥6 months. In 2004, influenza-associated deaths in children became a notifiable condition.MethodsDeaths that occurred in children aged <18 years with laboratory-confirmed influenza virus infection were reported from states andterritories to the Centers for Disease Control and Prevention on astandard case report form. We used population estimates from theU.S. Census Bureau, 2011 to 2015, to calculate age group-adjustedincidence. We used Wilcoxon-rank-sum test to compare medians andchi-square and Mantel-Haenszel chi-square to compare differencesbetween proportions of two groups.ResultsFrom October 2010 through September 2015, 590 influenza-associated pediatric deaths were reported. The median age at timeof death was 6 years (interquartile range, 1–12 years). Half of thechildren (285/572) had at least one underlying medical condition.Neurologic conditions (26%) and development delay (21%) weremost commonly reported. The average annual incidence rate was0.16 per 100,000 children (95% confidence interval [CI]: 0.15–0.17)and was highest among children aged <6 months (0.75, 95% CI,0.60–0.94 per 100,000 children), followed by children aged6–23 months (0.34, 95% CI, 0.28–0.41 per 100,000 children). Only21% (87/409) of pediatric deaths in children≥6 months had evidenceof full influenza vaccination. Vaccination coverage was lower inchildren aged 6–23 months (15%) and 5–8 years (17%) than withthose aged 2–4 years and 9–17 years (25%, p<0.01). The majorityof children aged <2 years who died had no underlying medicalconditions (63%, 105/167); this proportion was significantly higherthan that in children aged≥2 years (45%, 182/405, p<0.01).Overall 65% (383) of pediatric deaths had influenza A virusdetected, and 33% had influenza B virus detected. Children infectedwith influenza B virus had a higher frequency of sepsis/shock(41%, 72/174), acute respiratory distress syndrome (ARDS, 33%,58/174), and hemorrhagic pneumonia/pneumonitis (8%, 14/174) thanchildren infected with either influenza A(H1N1) pdm09 or influenzaA(H3N2) virus (p=0.01, 0.03, 0.03, respectively).Overall 81% (421/521) of children had an influenza-associatedcomplication; the most commonly reported were pneumonia (40%),sepsis/shock (31%) and ARDS (29%). Among those with testingreported, invasive bacteria coinfections were identified in 43%(139/322);β-hemolyticStreptococcus(20%) andStaphylococcusaureus(17%) were reported most frequently.Most children (39%, 212/548) died within 3 days of symptomonset, 28% died 4–7 days after onset, and 34% died≥8 days afteronset. The median days from illness onset to death for children withan underlying condition was significantly longer than the time forpreviously healthy children (7 versus 4 days, p<0.01).ConclusionsEach year, a substantial number of influenza-associated deathsoccur among U.S. children, with rates highest among those aged<2 years. While half of the deaths were among children withunderlying conditions, the majority of children <2 years who diedwere previously healthy. Vaccination coverage was very low.Influenza vaccination among pregnant women, young children andchildren with high-risk underlying conditions should be encouragedand could reduce influenza-associated mortality among children.

Minimal Transmission in an Influenza A (H3N2) Human Challenge-Transmission Model with Exposure Events in a Controlled Environment

2019 ◽  
Author(s):  
Jonathan S. Nguyen-Van-Tam ◽  
Ben Killingley ◽  
Joanne Enstone ◽  
Michael Hewitt ◽  
Jovan Pantelic ◽  
...  
Keyword(s):  
Influenza A ◽  
Transmission Model ◽  
Controlled Environment

Vaccination and immunization status among healthcare students: results from the SAVES survey

2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
S Rivolta ◽  
M Letzgus ◽  
F De Nard ◽  
M Gaiazzi ◽  
N Principi ◽  
...  
Keyword(s):  
High Risk ◽  
Sex Education ◽  
Vaccination Coverage ◽  
Medical Residents ◽  
Natural Immunity ◽  
Healthcare Facilities ◽  
Healthcare Students ◽  
Immunization Status ◽  
Healthcare Professions ◽  
The University

Abstract Background Adequate vaccination coverage among healthcare workers, including students in healthcare professions (SHPs), is crucial in order to prevent spreading of infections within healthcare facilities. However, vaccination coverage among SHPs is often inadequate. We aimed to describe the vaccination/immunization status of SHPs of the University of Milan. Methods We spread an e-survey to the academic e-mail addresses of postgraduate medical residents and to first- and last-year undergraduate SHPs. The questionnaire covered sociodemographic data (age, sex, education, municipality of residence, internship in high-risk wards) and the reported vaccination/immunization status for Influenza (previous flu season), Varicella, MPR and DTaP vaccines. Results Among 5743 invited SHPs, 884 participated in the survey. The study sample comprised 462 medical residents and 422 undergraduate SHPs (medicine 176, nursery 186, midwifery 4, healthcare assistance 32, prevention techniques 24). Median age was 27 years (IQR 7); 68.4% participants were female; 91.3% had attended high school in a lyceum, while others in a professional (2.9%) or technical (5.8%) institute; 36.7% lived in municipalities of &lt; 20.000 inhabitants, while 26.1% of &gt; 250.000. Traineeships took place in high-risk wards for 46% of participants. Reported vaccination coverage for Influenza was 33,7% (with higher coverage for pediatric nursing and midwifery students, medicine students and medical residents). Participants reported immunity (either vaccine or natural immunity) to Varicella in 93,3% cases. Declared vaccination coverage for Hepatitis B was 94,1%; 91,7% participants reportedly completed the MPR schedule, 76,2% the recommended DTaP booster. Conclusions Influenza vaccination coverage was suboptimal in our sample of SHPs, suggesting the need of specific educational programs and targeted vaccination campaigns, which may help shaping a positive vaccination attitude for future healthcare professionals. Key messages Immunization status for VPDs is suboptimal among Italian students in healthcare professions. The monitoring of the immunization status should include healthcare students actively involved in healthcare activities.

scholarly journals 286. Exploratory Cost-Effectiveness Analysis for Treatment of Methicillin-Resistant Staphylococcus aureus Bloodstream Infections: Are Daptomycin and Linezolid Favored over Vancomycin and Other Antibiotics?

2020 ◽  
Vol 7 (Supplement_1) ◽  
pp. S143-S144
Author(s):  
Michelle Vu ◽  
Kenneth Smith ◽  
Sherrie L Aspinall ◽  
Cornelius J Clancy ◽  
Deanna Buehrle
Keyword(s):  
Staphylococcus Aureus ◽  
Cost Effectiveness ◽  
Methicillin Resistant Staphylococcus Aureus ◽  
Bloodstream Infections ◽  
Sensitivity Analyses ◽  
Drug Event ◽  
Base Case ◽  
Health Administration ◽  
Research Support ◽  
Methicillin Resistant

Abstract Background Methicillin-resistant Staphylococcus aureus bloodstream infections (MRSAB) cause significant mortality and often require extended antibiotic therapy. Vancomycin, the most common initial MRSAB treatment, carries significant monitoring burden and nephrotoxicity risks. We compared cost-effectiveness of vancomycin and other antibiotic regimens as MRSAB treatment. Methods We estimated cost-effectiveness of intravenous antibiotics (vancomycin, daptomycin, linezolid, ceftaroline/daptomycin, dalbavancin) for Veterans Health Administration (VA) patients with MRSAB using an exploratory decision-tree model. Primary effectiveness outcome was composite of microbiological failure and adverse drug event (ADE)-related discontinuation at 7-days. Results In base-case analyses, linezolid and daptomycin were less expensive and had fewer treatment failures than other regimens at 4 and 6-weeks. Compared to linezolid, daptomycin incremental cost-effectiveness ratios were ~$45,000 (4-weeks) and ~$61,000 (6-weeks) per composite failure avoided, respectively. In one-way sensitivity analyses, daptomycin (4-weeks) was favored over linezolid if linezolid microbiological failure or ADE-related discontinuation rates were &gt;14.8% (base case: 14.0%) or &gt;14.3% (base case: 14.0%), respectively, assuming a willingness to pay (WTP) threshold of $40,000/ composite treatment failure avoided. Vancomycin was favored if its microbiological failure risk was &lt; 16.4% (base case: 27.2%). In two-way sensitivity analyses, daptomycin was favored if linezolid microbiological failure and ADE-related discontinuation rates were &gt;19% and &gt; 16%, respectively. Linezolid, daptomycin and vancomycin were favored in 47%, 39%, and 11% of 4-week probabilistic iterations, respectively, at $40,000 WTP. Conclusion Daptomycin or linezolid are likely less expensive and more effective than vancomycin or other initial regimens for MRSAB. More data are needed to support safety of linezolid in MRSAB patients. Disclosures Cornelius J. Clancy, MD, Astellas (Consultant, Grant/Research Support)Cidara (Consultant, Research Grant or Support)Melinta (Grant/Research Support)Merck (Consultant, Grant/Research Support)Needham Associates (Consultant)Qpex (Consultant)Scynexis (Consultant)Shionogi (Consultant)

scholarly journals Cost-effectiveness analysis of ranibizumab for retinal vein occlusion patients in China from the societal perspective

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Weiyi Ni ◽  
Jia Liu ◽  
Yawen Jiang ◽  
Jing Wu
Keyword(s):  
Cost Effectiveness ◽  
Retinal Vein Occlusion ◽  
Societal Perspective ◽  
Laser Photocoagulation ◽  
Cost Effective ◽  
Sensitivity Analyses ◽  
Gdp Per Capita ◽  
Base Case ◽  
Vein Occlusion ◽  
Per Capita

Abstract Background Clinical trials in China have demonstrated that ranibizumab can improve the clinical outcomes of branch retinal vein occlusion (BRVO) and central retinal vein occlusion (CRVO). However, no economic evaluation of ranibizumab has been conducted among Chinese patient population. Methods To provide insights into the economic profile of ranibizumab among Chinese RVO population, a Markov state-transition model was used to predict the outcomes of ranibizumab comparing to laser photocoagulation and observational-only care from the societal perspective. This model simulated changes in patient visuality, quality-adjusted of life years (QALY), medical costs, and direct non-medical costs of individuals with visual impairment due to BRVO or CRVO in lifetime. The base-case analysis used an annual discount rate of 5% for costs and benefits following the China Guidelines for Pharmacoeconomic Evaluations. Deterministic and probabilistic sensitivity analyses were performed to test the robustness of the model. Results The base-case incremental cost-effectiveness ratio (ICER) comparing ranibizumab to laser photocoagulation was ¥65,008/QALY among BRVO patients and was ¥65,815/QALY among CRVO patients, respectively. Comparing to the 2019 gross domestic product (GDP) per capita of ¥71,000, both two ICERs were far below the cost-effective threshold at three times of GDP per capita (¥213,000). The deterministic and probabilistic sensitivity analyses demonstrated the base-case results were robust in most of the simulation scenarios. Conclusion The current Markov model demonstrated that ranibizumab may be cost-effective compared with laser photocoagulation to treat BRVO and cost-effective compared to observation-only care to treat CRVO in China from the societal perspective.

Abstract 15595: Missed Targets: United States Trends in Hypertension Prevalence, Control, and Treatment 2005-2018

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Rahul Aggarwal ◽  
Nicholas Chiu ◽  
Rishi Wadhera ◽  
Changyu Shen ◽  
Robert W Yeh ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Temporal Trends ◽  
Cost Effective ◽  
Pressure Control ◽  
Healthy People ◽  
Sensitivity Analyses ◽  
Base Case ◽  
Improve Blood Pressure Control ◽  
Hypertension Prevalence ◽  
And Control

Introduction: Hypertension is a major risk factor for cardiovascular disease. The US government, through the Healthy People Initiative 2020, set targets to improve hypertension prevalence and treatment rates in US adults by a relative 10% from 2005 to 2020, and increase control rates by a relative 40%. We examined US progress towards this goal from 2005-2018. Methods: We analyzed data from 38,876 non-pregnant US adults from the NHANES 2005-2018 surveys to determine nationally representative estimates of hypertension prevalence, treatment rates, and control. Temporal trends in hypertension prevalence, treatment, and control were assessed using weighted linear regression after age adjustment to the 2000 US census (per the Healthy People Initiative approach). In the base case, we defined hypertension as blood pressure >140/90 or on an antihypertensive; we used the ACC/AHA definition of blood pressure >130/80 in sensitivity analyses. Results: In 2017-2018, 34.3% (±1.7) of US adults had hypertension, of these 69.7% (±1.5) were on treatment, and 43.7% (±1.6) were controlled. After age-adjustment, no statistically significant changes in hypertension prevalence, treatment rates, or control were observed from 2005-2018 (p for trend 0.91, ,0.98, 0.66, Figure 1). In sensitivity analyses, applying the ACC/AHA definition increased the estimated prevalence of hypertension during the period, but trends in prevalence remained unchanged. Conclusions: There has been no material progress in reducing the prevalence of hypertension or improving rates of treatment and control from 2005 to 2018. As planning is underway for Healthy People Initiative 2030, setting of hypertension targets must be accompanied with investments in cost-effective, scalable programs to improve blood pressure control nationwide, with a focus on high-risk populations.

scholarly journals Avian Influenza A (H7N9) Model Based on Poultry Transport Network in China

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Juping Zhang ◽  
Wenjun Jing ◽  
Wenyi Zhang ◽  
Zhen Jin
Keyword(s):  
Avian Influenza ◽  
Influenza A ◽  
Suitable Condition ◽  
Threshold Value ◽  
Transport Network ◽  
Transmission Model ◽  
Poultry Farm ◽  
Wholesale Market ◽  
Backyard Poultry ◽  
Live Poultry

In order to analyze the spread of avian influenza A (H7N9), we construct an avian influenza transmission model from poultry (including poultry farm, backyard poultry farm, live-poultry wholesale market, and wet market) to human according to poultry transport network. We obtain the threshold value for the prevalence of avian influenza A (H7N9) and also give the existence and number of the boundary equilibria and endemic equilibria in different conditions. We can see that poultry transport network plays an important role in controlling avian influenza A (H7N9). Finally, numerical simulations are presented to illustrate the effects of poultry in different places on avian influenza. In order to reduce human infections in China, our results suggest that closing the retail live-poultry market or preventing the poultry of backyard poultry farm into the live-poultry market is feasible in a suitable condition.

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