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To assess the impact of absolute humidity on influenza transmission in Beijing from 2014 to 2019, we estimated the influenza transmissibility via the instantaneous reproduction number (Rt), and evaluated its nonlinear exposure-response association and delayed effects with absolute humidity by using the distributed lag nonlinear model (DLNM). Attributable fraction (AF) of Rt due to absolute humidity was calculated. The result showed a significant M-shaped relationship between Rt and absolute humidity. Compared with the effect of high absolute humidity, the low absolute humidity effect was more immediate with the most significant effect observed at lag 6 days. AFs were relatively high for the group aged 15-24 years, and was the lowest for the group aged 0-4 years with low absolute humidity. Therefore, we concluded that the component attributed to the low absolute humidity effect is greater. Young and middle-aged people are more sensitive to low absolute humidity than children and elderly.
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Gripe Humana , Niño , Anciano , Persona de Mediana Edad , Humanos , Beijing/epidemiología , Gripe Humana/epidemiología , Humedad , China/epidemiología , Medición de Riesgo , TemperaturaRESUMEN
What is already known about this topic?: China has repeatedly contained multiple severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreaks through a comprehensive set of targeted non-pharmaceutical interventions (NPIs). However, the effectiveness of such NPIs has not been systematically assessed. What is added by this report?: A multilayer deployment of case isolation, contact tracing, targeted community lockdowns, and mobility restrictions could potentially contain outbreaks caused by the SARS-CoV-2 ancestral strain, without the requirement of city-wide lockdowns. Mass testing could further aid in the efficacy and speed of containment. What are the implications for public health practice?: Pursuing containment in a timely fashion at the beginning of the pandemic, before the virus had the opportunity to spread and undergo extensive adaptive evolution, could help in averting an overall pandemic disease burden and be socioeconomically cost-effective.
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With COVID-19 public health control measures downgraded in China in January 2023, reported COVID-19 case numbers may underestimate the true numbers after the SARS-CoV-2 Omicron wave. Using a multiplier model based on our influenza surveillance system, we estimated that the overall incidence of SARS-CoV-2 infections was 392/100,000 population in Beijing during the 5 weeks following policy adjustment. No notable change occurred after the Spring Festival in early February. The multiplier model provides an opportunity for assessing the actual COVID-19 situation.
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COVID-19 , Gripe Humana , Humanos , Beijing/epidemiología , SARS-CoV-2 , Gripe Humana/diagnóstico , Gripe Humana/epidemiología , China/epidemiologíaRESUMEN
Airborne transmissibility of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has highlighted the urgent need for aerosol monitoring of SARS-CoV-2 to prevent sporadic outbreaks of COVID-19. The inadequate sensitivity of conventional methods and the lack of an on-site detection system limited the practical SARS-CoV-2 monitoring of aerosols in public spaces. We have developed a novel SARS-CoV-2-in-aerosol monitoring system (SIAMs) which consists of multiple portable cyclone samplers for collecting aerosols from several venues and a sensitive "sample-to-answer" microsystem employing an integrated cartridge for the analysis of SARS-CoV-2 in aerosols (iCASA) near the sampling site. By seamlessly combining viral RNA extraction based on a chitosan-modified quartz filter and "in situ" tetra-primer recombinase polymerase amplification (tpRPA) into an integrated microfluidic cartridge, iCASA can provide an ultra-high sensitivity of 20 copies/mL, which is nearly one order of magnitude greater than that of the commercial kit, and a short turnaround time of 25 min. By testing various clinical samples of nasopharyngeal swabs, saliva, and exhaled breath condensates obtained from 23 COVID-19 patients, we demonstrate that the positive rate of our system was 3.3 times higher than those of the conventional method. Combining with multiple portable cyclone samplers, we detected 52.2% (12/23) of the aerosol samples, six times higher than that of the commercial kit, collected from the isolation wards of COVID-19 patients, demonstrating the excellent performance of our system for SARS-CoV-2-in-aerosol monitoring. We envision the broad application of our microsystem in aerosol monitoring for fighting the COVID-19 pandemic.
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Prior to the emergence of the Omicron variant, many cities in China had been able to maintain a "Zero-COVID" policy. They were able to achieve this without blanket city-wide lockdown and through widespread testing and an extensive set of nonpharmaceutical interventions (NPIs), such as mask wearing, contact tracing, and social distancing. We wanted to examine the effectiveness of such a policy in containing SARS-CoV-2 in the early stage of the pandemic. Therefore, we developed a fully stochastic, spatially structured, agent-based model of SARS-CoV-2 ancestral strain and reconstructed the Beijing Xinfadi outbreak through computational simulations. We found that screening for symptoms and among high-risk populations served as methods to discover cryptic community transmission in the early stage of the outbreak. Effective contact tracing could greatly reduce transmission. Targeted community lockdown and temporal mobility restriction could slow down the spatial spread of the virus, with much less of the population being affected. Population-wide mass testing could further improve the speed at which the outbreak is contained. Our analysis suggests that the containment of SARS-CoV-2 ancestral strains was certainly possible. Outbreak suppression and containment at the beginning of the pandemic, before the virus had the opportunity to undergo extensive adaptive evolution with increasing fitness in the human population, could be much more cost-effective in averting the overall pandemic disease burden and socioeconomic cost.
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To estimate the effect of the corona virus disease 2019 (COVID-19) control measures taken to mitigate community transmission in many regions, we analyzed data from the influenza surveillance system in Beijing from week 27 of 2014 to week 26 of 2020. We collected weekly numbers of influenza-like illness (ILI) cases, weekly positive proportion of ILI cases, weekly ILI case proportion in outpatients, and the dates of implementation of COVID-19 measures. We compared the influenza activity indicators of the 2019/2020 season with the preceding five seasons and built two ARIMAX models to estimate the effectiveness of COVID-19 measures declared since January 24, 2020 by the emergency response. Based on the observed data, compared to the preceding five influenza seasons, ILIs, positive proportion of ILIs, and duration of the influenza epidemic period in 2019/2020 had increased from 13% to 54%; in particular, the number of weeks from the peak to the end of the influenza epidemic period had decreased from 12 to 1. According to ARIMAX model forecasting, after considering natural decline, weekly ILIs had decreased by 48.6%, weekly positive proportion had dropped by 15% in the second week after the emergency response was declared, and COVID-19 measures had reduced by 83%. We conclude that the public health emergency response can significantly interrupt the transmission of influenza.
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COVID-19 , Gripe Humana , Virosis , Beijing/epidemiología , COVID-19/epidemiología , Humanos , Gripe Humana/epidemiología , Gripe Humana/prevención & control , Salud Pública , Estaciones del AñoRESUMEN
BACKGROUND: The presymptomatic transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been documented in limited clusters, and it is predicted through modelling. However, there is a lack of evidence from observations with a large sample size. METHODS: We used data from meticulous contact tracing of people exposed to cases of SARS-CoV-2 to estimate the proportion of cases that result from the presymptomatic transmission of the virus in Beijing during January 2020 and February 2020. RESULTS: The results showed that presymptomatic transmission occurred in at least 15% of 100 secondary COVID-19 cases. The earliest presymptomatic contact event occurred 5 days prior to the index case's onset of symptoms, and this occurred in two clusters. CONCLUSIONS: The finding suggested that the contact tracing period should be earlier and highlighted the importance of preventing transmission opportunities well before the onset of symptoms.
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Infecciones Asintomáticas/epidemiología , COVID-19/transmisión , Portador Sano/virología , Brotes de Enfermedades , SARS-CoV-2/aislamiento & purificación , Adulto , Enfermedades Asintomáticas , COVID-19/diagnóstico , COVID-19/epidemiología , Prueba de Ácido Nucleico para COVID-19 , Portador Sano/epidemiología , China/epidemiología , Trazado de Contacto , Femenino , Humanos , Masculino , Persona de Mediana Edad , SARS-CoV-2/genéticaRESUMEN
Although schools are known to play a major role in the spread of influenza virus, few studies have evaluated the effectiveness of vaccination and non-pharmaceutical measures for preventing influenza outbreaks in schools. We investigated all febrile illness outbreaks in primary and secondary schools in Beijing reported between August 2018 and July 2019. We obtained epidemiological information on febrile illness outbreaks and oral pharyngeal swabs from students in the outbreaks to test for influenza virus. We surveyed schools that did not report febrile illness outbreaks. We developed multi-level models to identify and evaluate factors associated with serious influenza outbreaks and explored the association of vaccine coverage and outbreaks using multi-stage regression models. We identified a total of 748 febrile illness outbreaks involving 8176 students in Beijing; 462 outbreaks were caused by influenza virus. Adjusted regression modeling showed that large class size (odds ratio (OR) = 2.38) and the number of days from identification of the first case to initiation of an intervention (OR = 1.17) were statistically significant and positively associated with serious outbreaks, and that high vaccination coverage (relative risk (RR) = 0.50) was statistically significant and negatively associated with outbreaks. Multi-stage regression modeling showed that RR decreased fastest when vaccination coverage was 45% to 51%. We conclude that high influenza vaccination coverage can prevent influenza outbreaks in schools and that rapid identification of febrile children and early initiation of non-pharmaceutical measures can reduce outbreak size.
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OBJECTIVE: This study comprehensively estimated the excess cardiovascular disease (CVD) mortality attributable to influenza in an older (age ≥65 years) population. DESIGN: Ecological study. SETTING: Aggregated data from administrative systems on CVD mortality, influenza surveillance and meteorological data in Beijing, China. MAIN OUTCOME MEASURE: Excess overall CVD, and separately for ischaemic heart disease (IHD), ischaemic stroke, haemorrhagic stroke mortality attributable to influenza, adjusting for influenza activity, time trend, seasonality and ambient temperature. RESULTS: CVD (risk ratio (RR) 1.02, 95% CI 1.01, 1.02), IHD (RR 1.01, 95% CI 1.01, 1.02), ischaemic stroke (RR=1.03, 95% CI 1.02, 1.04), but not haemorrhagic stroke (RR=1.00, 95% CI 0.99, 1.01) mortality, were significantly associated with every 10% increase in influenza activity. An increase in circulating A(H1N1)09pdm, A(H3N2) and B type virus were all significantly associated with CVD and ischaemic stroke mortality, but only A(H3N2) and B type virus with IHD mortality. The strongest increase in disease mortality was in the same week as the increase in influenza activity. Annual excess CVD mortality rate attributable to influenza ranged from 54 to 96 per 100 000 population. The 3%-6% CVD mortality attributable to influenza activity was related to an annual excess of 916-1640 CVD deaths in Beijing, China. CONCLUSIONS: Influenza activity has moderate to strong associations with CVD, IHD and ischaemic stroke mortality in older adults in China. Promoting influenza vaccination could have major health benefit in this population. BACKGROUND: Influenza may trigger serious CVD events. An estimation of excess CVD mortality attributable to influenza has particular relevance in China where vaccination is low and CVD burden is high. METHODS: This study analysed data at the population level (age ≥65 years) using linked aggregated data from administrative systems on CVD mortality, influenza surveillance and meteorological data during 2011 to 2018. Quasi-Poisson regression models were used to estimate the excess overall CVD, and separately for IHD, ischaemic stroke, haemorrhagic stroke mortality attributable to influenza, adjusting for influenza activity, time trend, seasonality and ambient temperature. Analyses were also undertaken for influenza subtypes (A(H1N1)09pdm, A(H3N2) and B viruses), and mortality risk with time lags of 1-5 weeks following influenza activity in the current week.
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Enfermedades Cardiovasculares , Subtipo H1N1 del Virus de la Influenza A , Gripe Humana , Beijing , Enfermedades Cardiovasculares/etiología , China/epidemiología , Humanos , Subtipo H3N2 del Virus de la Influenza A , Gripe Humana/complicacionesRESUMEN
Background: Since 2007, trivalent inactivated influenza vaccine (TIV) has been provided free-of-charge to primary, middle school and high school students in Beijing. However, there have been few school-based studies on influenza vaccine effectiveness (VE). In this report, we estimated influenza VE against laboratory-confirmed influenza illness among school children in Beijing, China during the 2016-2017 influenza season.Methods: The VE of 2016-2017 TIV against laboratory-confirmed influenza virus infection among school-age children was assessed through a case-control design. Conditional logistic regression was conducted on matched case-control sets to estimate VE. The effect of prior vaccination on current VE was also examined.Results: All 176 samples tested positive for influenza A virus with the positive rate of 55.5%. The average coverage rate of 2016-2017 TIV among students across the 37 schools was 30.6%. The fully adjusted VE of 2016-2017 TIV against laboratory-confirmed influenza was 69% (95% CI: 51 to 81): 60% (95% CI: -15 to 86) for influenza A(H1N1)pdm09 and 73% (95% CI: 52 to 84) for influenza A(H3N2). The overall VE for receipt of 2015-2016 vaccination only, 2016-2017 vaccination only, and vaccinations in both seasons was 46% (95% CI: -5 to 72), 77% (95% CI: 58 to 87), and 57% (95%CI: 17 to 78), respectively.Conclusions: Our study during school outbreaks found that VE of 2016-2017 TIV was moderate against influenza A(H3N2) as well as A(H1N1)pdm09 viruses.
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Subtipo H1N1 del Virus de la Influenza A , Vacunas contra la Influenza , Gripe Humana , Beijing/epidemiología , Estudios de Casos y Controles , Niño , China/epidemiología , Brotes de Enfermedades/prevención & control , Humanos , Subtipo H3N2 del Virus de la Influenza A , Gripe Humana/epidemiología , Gripe Humana/prevención & control , Instituciones Académicas , Estaciones del Año , VacunaciónRESUMEN
BACKGROUND: Few studies have reported on the seroprevalence of antibodies against avian influenza A (H9N2) virus and the incidence of these infections in the northern China and among swine workers. METHODS: We conducted a serological cohort study among people working with poultry or swine or the general population in Beijing, China. It comprised four cross-sectional serological surveys in November 2013, April 2014, April 2015, and April 2016. Blood samples collected from the participants were tested for anti-H9N2 antibodies using a hemagglutination-inhibition (HI) assay. Multivariable Poisson regression model was then used to compare the person-month incidence rates for H9N2 viral infections among the three groups, assessed by incidence rate ratio (IRR). RESULTS: In the four cross-sectional surveys, the highest seroprevalence of anti-H9N2 antibodies (HI titer ≥ 80) was recorded in the poultry workers (2.77%, 19/685) in April 2016, while the lowest was recorded in the general population (0.09%, 1/1135) in April 2015. The highest incidence density rate for H9N2 infections across the whole study period was recorded among the poultry workers (3.75/1000 person-months), followed by the swine workers (1.94/1000 person-months) and the general population (1.78/1000 person-months). Multivariable analysis showed that the poultry workers were at higher risk (IRR: 2.42, 95% CI: 1.07-5.48; P = 0.034) of contracting H9N2 virus than the general population. CONCLUSIONS: Although the seroprevalence of H9N2 antibodies was low in Beijing, the poultry workers were at higher risk of contracting H9N2 viral infections than the general population. Closer monitoring and strengthened protection measures for poultry workers are warranted.
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Agricultores/estadística & datos numéricos , Subtipo H9N2 del Virus de la Influenza A/aislamiento & purificación , Gripe Aviar/virología , Gripe Humana/epidemiología , Adulto , Animales , Anticuerpos Antivirales/sangre , China/epidemiología , Estudios de Cohortes , Estudios Transversales , Femenino , Pruebas de Inhibición de Hemaglutinación , Humanos , Gripe Aviar/transmisión , Gripe Humana/transmisión , Masculino , Persona de Mediana Edad , Aves de Corral/virología , Factores de Riesgo , Estudios Seroepidemiológicos , Porcinos/virologíaRESUMEN
BACKGROUND: Little is known about the vaccine effectiveness (VE) in attenuating the influenza-associated symptoms in children during the 2014-2015 influenza season in Beijing, China, in which there was a mismatch between the vaccine and circulating strain. METHODS: This study included 210 laboratory-confirmed influenza cases among children, who were enrolled in 2014, from November 1 to December 31. Standard demographic information and clinical symptoms were recorded. Influenza vaccination was confirmed via a vaccination registry. Univariate and multivariate analyses were used to estimate the odds of presenting with clinical symptoms among vaccinated and unvaccinated groups, adjusting for sex, age, area, BMI level, and chronic conditions. RESULTS: Among the 210 laboratory-confirmed influenza cases, 170 (81.0%) presented with fever ≥38°C. The other most common symptoms were cough (78.1%), sore throat (46.7%), nasal congestion/rhinorrhea (38.6%), headache (34.8%), fatigue (24.8%) and myalgia/arthralgia (16.2%). Approximately 9.0% (19/210) exhibited nausea/vomiting, and 2.4% (5/210) exhibited diarrhea/abdominal pain. Respiratory complications occurred in 5.7% (12/210) of the confirmed influenza cases. In 210 laboratory-confirmed cases, univariate and multivariate conducted after adjusted for the aforementioned characteristics suggested that the odds of fever ≥ 38°C were significantly reduced in vaccinated children (odds ratio [OR]: 0.42, 95% CI: 0.19-0.93; P = 0.033). CONCLUSIONS: Inï¬uenza vaccination may reduce the clinical symptoms of laboratory-confirmed influenza cases potentially even in the mismatching season.
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Subtipo H3N2 del Virus de la Influenza A/inmunología , Vacunas contra la Influenza/administración & dosificación , Gripe Humana/prevención & control , Potencia de la Vacuna , Adolescente , Beijing , Estudios de Casos y Controles , Niño , Femenino , Humanos , Subtipo H1N1 del Virus de la Influenza A/inmunología , Vacunas contra la Influenza/inmunología , Masculino , Estaciones del Año , VacunaciónRESUMEN
BACKGROUND: The objective of this study was to estimate influenza vaccine effectiveness (VE) for the 2016/17 epidemic of co-circulating influenza A(H1N1)pdm09 and A(H3N2) viruses in Beijing, the capital of China. METHODS: The surveillance-based study included all swabbed patients through influenza virological surveillance, between November 2016 and April 2017. A test-negative case-control design was used to estimate influenza VE against medically-attended laboratory-confirmed influenza in outpatient settings. Cases were influenza-like illness (ILI) patients who tested positive for influenza, and controls were influenza negative patients. RESULTS: A total of 10,496 ILI patients were enrolled and swabbed. Among them, 735 tested positive for influenza A(H1N1)pdm09, 1851 for A(H3N2), and 40 for type B. Of the 45 randomly selected specimens out of 1851 influenza A(H3N2) viruses, 2(4.4%) belonged to the H3N2 3C.2a1 clade, and 43(95.6%) belonged to A/Hong Kong/4801/2014-like 3C.2a clade. Among the 43 viruses of the 3C.2a clade, 32 viruses clustered in one subgroup carrying T131K, R142K and R261Q substitutions. The adjusted VE against all influenza was low at 25% (95% confidence interval (CI): 0-43%), with 54% (95%CI: 22-73%) for influenza A(H1N1)pdm09, and 2% (95%CI: -35% to 29%) for influenza A(H3N2). CONCLUSIONS: Our study suggested a moderate VE against influenza A(H1N1)pdm09, but low VE against influenza A(H3N2) in Beijing, 2016/17 season. Amino acid substitutions in the hemagglutinin may contribute to the low VE against influenza A(H3N2) for this season.
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Glicoproteínas Hemaglutininas del Virus de la Influenza/genética , Subtipo H1N1 del Virus de la Influenza A/inmunología , Subtipo H3N2 del Virus de la Influenza A/inmunología , Vacunas contra la Influenza/inmunología , Gripe Humana/epidemiología , Gripe Humana/prevención & control , Potencia de la Vacuna , Adolescente , Adulto , Estudios de Casos y Controles , Niño , Preescolar , China/epidemiología , Femenino , Humanos , Lactante , Subtipo H1N1 del Virus de la Influenza A/clasificación , Subtipo H1N1 del Virus de la Influenza A/genética , Subtipo H3N2 del Virus de la Influenza A/clasificación , Subtipo H3N2 del Virus de la Influenza A/genética , Masculino , Persona de Mediana Edad , Pacientes Ambulatorios , Vigilancia de Guardia , Encuestas y Cuestionarios , Vacunación , Adulto JovenRESUMEN
BACKGROUND: Since 2007, trivalent inactivated influenza vaccine has been provided free-of-charge to older adults aged ≥60 years in Beijing, China, but the data regarding influenza vaccine effectiveness (VE) among these people are very limited so far. We sought to estimate influenza VE against medically-attended laboratory-confirmed influenza illness among older adults during the 2013-2014 season. METHODS: The influenza-like illness (ILI) patients aged 60 years and older who participated in the influenza virological surveillance of Beijing during 2013-2014 influenza season were recruited in this study. A test-negative design was employed to estimate influenza VE among older adults by using logistic regression models. VE was estimated using logistic regression, adjusted for sex, age, interval (days) between illness onset and specimen collection, and week of illness onset. RESULTS: Between 1 November, 2013 and 30 April, 2014, a total of 487 elderly ILI patients were enrolled in the study, including 133 influenza-positive cases (of whom 6.8% were vaccinated) and 354 influenza-negative controls (of whom 10.2% were vaccinated). Among 133 influenza-positive cases, 51 tested positive for A(H1N1)pdm09 virus, 22 positive for A(H3N2) virus, 52 tested positive for B/Yamagata-lineage virus, 2 positive for B/Victoria-lineage virus, 1 positive for both A(H1N1)pdm09 and A(H3N2) viruses, and 5 tested positive for viruses of unknown subtype or lineage. The adjusted overall VE was estimated as 32% (95% CI:-48-69), with 59% (95% CI: -79-90) against A(H1N1)pdm09, 22% (95% CI: -253-83) against A(H3N2) and -20% (95% CI: -239-58) against B/Yamagata-lineage viruses. CONCLUSIONS: These results suggested a modest protective effect of the 2013-2014 influenza vaccine among older adults in Beijing which was not statistically significant, with higher VE against the A(H1N1)pdm09 viruses compared to A(H3N2) and B viruses.
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Subtipo H1N1 del Virus de la Influenza A/inmunología , Subtipo H3N2 del Virus de la Influenza A/inmunología , Vacunas contra la Influenza/inmunología , Gripe Humana/prevención & control , Adulto , Anciano , Anciano de 80 o más Años , Beijing , Femenino , Humanos , Vacunas contra la Influenza/administración & dosificación , Masculino , Persona de Mediana Edad , Resultado del TratamientoRESUMEN
BACKGROUND: The present study aimed to estimate residents' willingness to accept a future H7N9 vaccine and its determinants in the general adult population in Beijing, China. METHODS: We conducted a multi-stage sampling, cross-sectional survey using self-administered anonymous questionnaires from May to June, in 2014. The main outcome variable was residents' willingness to accept a future H7N9 vaccine. Logistic regression was used to identify the predictors of vaccination willingness. RESULTS: Of the 7264 eligible participants, 14.5% of Beijing residents reported that they had not heard of H7N9. Among those who had heard of H7N9, 59.5% of the general adult population would be willing to accept a future H7N9 vaccine, and approximately half of them reported 'I am afraid of being infected by H7N9' and 'H7N9 vaccine can prevent infections', and 28.1% reported 'my daily life is affected by H7N9'. The variables that were significantly associated with a higher likelihood of reporting willingness were being younger adults (aged 18-29â¯years: ORâ¯=â¯1.52, 95% CI: 1.17-1.97; aged 30-39â¯years: ORâ¯=â¯1.39, 95% CI: 1.08-1.78), being farmers (ORâ¯=â¯1.61; 95% CI: 1.32-1.96), being unemployed people (ORâ¯=â¯1.36; 95% CI: 1.04-1.78), living in suburban areas (ORâ¯=â¯2.18; 95% CI: 1.89-2.51), having ≥2 children in the family (ORâ¯=â¯1.41; 95% CI: 1.03-1.92), perceived risk in China (ORâ¯=â¯1.30; 95% CI: 1.15-1.48), perceived susceptibility to disease (ORâ¯=â¯3.13; 95% CI: 2.73-3.58), perceived negative effect on daily life (ORâ¯=â¯1.32; 95% CI: 1.13-1.55), perceived effectiveness of vaccination (ORâ¯=â¯2.34; 95% CI: 2.07-2.64), and recent uptake of influenza vaccine (ORâ¯=â¯2.26; 95% CI: 1.92-2.66). CONCLUSIONS: A great number of Beijing residents had doubts about the vaccine's effectiveness and were not concerned about disease risk, which were the factors affecting willingness to be vaccinated. Targeted education programs on disease risk as well as vaccine's effectiveness are needed to improve the willingness of vaccination for potential H7N9 pandemic preparedness.
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Vacunas contra la Influenza , Gripe Humana/epidemiología , Aceptación de la Atención de Salud , Adolescente , Adulto , Anciano , Beijing/epidemiología , Estudios Transversales , Femenino , Conocimientos, Actitudes y Práctica en Salud , Humanos , Subtipo H7N9 del Virus de la Influenza A/inmunología , Vacunas contra la Influenza/administración & dosificación , Vacunas contra la Influenza/inmunología , Gripe Humana/prevención & control , Masculino , Persona de Mediana Edad , Vigilancia de la Población , Encuestas y Cuestionarios , Vacunación , Adulto JovenRESUMEN
BACKGROUND: Data about influenza mortality burden in northern China are limited. This study estimated mortality burden in Beijing associated with seasonal influenza from 2007 to 2013 and the 2009 H1N1 pandemic. METHODS: We estimated influenza-associated excess mortality by fitting a negative binomial model using weekly mortality data as the outcome of interest with the percent of influenza-positive samples by type/subtype as predictor variables. RESULTS: From 2007 to 2013, an average of 2375 (CI 1002-8688) deaths was attributed to influenza per season, accounting for 3% of all deaths. Overall, 81% of the deaths attributed to influenza occurred in adults aged ≥65 years, and the influenza-associated mortality rate in this age group was higher than the rate among those aged <65 years (113.6 [CI 49.5-397.4] versus 4.4 [CI 1.7-18.6] per 100 000, P < .05). The mortality rate associated with the 2009 H1N1 pandemic in 2009/2010 was comparable to that of seasonal influenza during the seasonal years (19.9 [CI 10.4-33.1] vs 17.2 [CI 7.2-67.5] per 100 000). People aged <65 years represented a greater proportion of all deaths during the influenza A(H1N1)pdm09 pandemic period than during the seasonal epidemics (27.0% vs 17.7%, P < .05). CONCLUSIONS: Influenza is an important contributor to mortality in Beijing, especially among those aged ≥65 years. These results support current policies to give priority to older adults for seasonal influenza vaccination and help to define the populations at highest risk for death that could be targeted for pandemic influenza vaccination.
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Subtipo H1N1 del Virus de la Influenza A , Gripe Humana/epidemiología , Gripe Humana/mortalidad , Pandemias/estadística & datos numéricos , Adulto , Anciano , Envejecimiento , Beijing/epidemiología , Humanos , Gripe Humana/virología , Persona de Mediana Edad , Estaciones del AñoRESUMEN
This study was aimed to develop an instrument to assess infectious disease-specific health literacy (IDSHL) in the general population of Tibet, China and identify the association between IDSHL and reported infectious disease-related symptoms. A survey using a standardized questionnaire, which included 25 questions on knowledge, behaviors and skills regarding infectious diseases, was conducted in the general population of Tibet, China between September 2011 and November 2011. The 25 questions formed the index system of the instrument assessing IDSHL (total scores: 25 scores). Factors associated with index scores of IDSHL were identified by general linear model. The association between the index score of IDSHL and the occurrence of the five selected infectious disease symptoms (fever, diarrhea, rash, jaundice or conjunctivitis) were investigated using multivariate unconditional logistic regression. Among 5717 eligible participants in the survey, 4631 participants completed all of the 25 questions in the instrument. The instrument was reliable and valid as measured by the Cronbach's alpha coefficient and split-half coefficient, and the confirmatory factor analysis. Only 1.0% (48/4631) answered ≥80% of the 25 questions correctly (score ≥ 20). Significant factors associated with lower health literacy score included female gender, older age, Tibetan group, lower education level, underlying diseases and more undeveloped area. For each increasing score of IDSHL, reports of fever, diarrhea or jaundice in the prior year were significantly decreased by 3% (p = 0.015), 4% (p = 0.004) and 16% (p < 0.001), respectively. Accurately measuring IDSHL could help identify those individuals with poor IDSHL, who could be targeted with specific interventions to improve health.
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Enfermedades Transmisibles , Alfabetización en Salud/estadística & datos numéricos , Adulto , Enfermedades Transmisibles/etiología , Enfermedades Transmisibles/terapia , Estudios Transversales , Femenino , Humanos , Masculino , Reproducibilidad de los Resultados , Encuestas y Cuestionarios , TibetRESUMEN
Influenza vaccination is the most effective way to reduce the incidence of influenza infections. However, the role of influenza vaccination, such as school-based influenza vaccination, in preventing the influenza outbreaks in schools remains unclear now. In this study, a total of 286 school febrile outbreaks involving 6863 cases in the Beijing area from September 1, 2006 to March 31, 2017 were analyzed. We also tested 294 circulating strains isolated in Beijing during the same period and compared with that of vaccine strains identified every influenza season. The virological match/mismatch between vaccine strains and circulating strains, and the coverage of vaccination in schools were analyzed against outbreaks during the 11â¯years. It showed that over 80% school febrile outbreaks were caused by influenza A/B virus, the most frequent being A(H3N2) virus (53.25%), followed by A(H1N1)pdm09 virus (25.11%) and B virus (21.64%). More importantly, low vaccine coverage (in 2006-2007 influenza season) and vaccine mismatch (in 2014-2015 and 2015-2016 influenza season) were associated with an increased number of influenza school outbreaks. High vaccination coverage with a matched vaccine can significantly reduce influenza outbreaks in schools (OR: 0.111, pâ¯<â¯.001). We have shown the effectiveness of school-based influenza vaccination in preventing outbreaks using trivalent inactivated influenza vaccine in schools. Thus the school-based vaccine policy should be paid more attention in China and other countries worldwide.