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Background. Data on risk factors for severe outcomes from 2009 pandemic influenza A (H1N1) virus infection are limited outside of developed countries. Methods. We reviewed medical charts to collect data from patients hospitalized with laboratory-confirmed 2009 H1N1 infection who were identified across China during the period from September 2009 through February 2010, and we analyzed potential risk factors associated with severe illness (defined as illness requiring intensive care unit admission or resulting in death). Results. Among 9966 case patients, the prevalence of chronic medical conditions (33% vs 14%), pregnancy (15% vs 7%), or obesity (19% vs 14%) was significantly higher in those patients with severe illness than it was in those with less severe disease. In multivariable analyses, among nonpregnant case patients aged ⩾2 years, having a chronic medical condition significantly increased the risk of severe outcome among all age groups, and obesity was a risk factor among those <60 years of age. The risk of severe illness among pregnant case patients was significantly higher for those in the second and third trimesters. The risk of severe illness was increased when oseltamivir treatment was initiated ⩾5 days after illness onset (odds ratio, 1.42; 95% confidence interval, 1.20-1.67). For persons <60 years of age, the prevalence of obesity among case patients with severe illness was significantly greater than it was among those without severe illness or among the general population. Conclusions. Risk factors for severe 2009 H1N1 illness in China were similar to those observed in developed countries, but there was a lower prevalence of chronic medical conditions and a lower prevalence of obesity. Obesity was a risk factor among case patients <60 years of age. Early initiation of oseltamivir treatment was most beneficial, and there was an increased risk of severe disease when treatment was started ⩾5 days after illness onset. [ABSTRACT FROM AUTHOR]

Objective To investigate the contextual risk factors for the regional distribution of Japanese encephalitis (JE) in the People’s Republic of China to enhance the prevention and control of JE. Methods A multilevel Poisson regression model was used to analyse the association between the epidemic of JE and its contextual risk factors with an emphasis on the proportion of rice-planting area, the extent of pig rearing and the proportion of rural population. Results The highest risk of JE was observed in the southwestern and the central areas of P.R. China, characterized by high proportions of rice-planting area, rural population and extent of pig rearing. These contextual determinants seem to govern the risk of JE. Conclusion In P.R. China, an effective surveillance system should be established in the high-risk regions of JE; immunization coverage for the prevention of JE should be expanded in rural areas, and mosquito-control efforts should be made to enhance the prevention and control of JE. [ABSTRACT FROM AUTHOR]

Problem In 2003, China's handling of the early stages of the epidemic of severe acute respiratory syndrome (SARS) was heavily criticized and generally considered to be suboptimal. Approach Following the SARS outbreak, China made huge investments to improve surveillance, emergency preparedness and response capacity and strengthen public health institutions. In 2013, the return on these investments was evaluated by investigating China's early response to the emergence of avian influenza A(H7N9) virus in humans. Local setting Clusters of human infection with a novel influenza virus were detected in China--by national surveillance of pneumonia of unknown etiology--on 26 February 2013. Relevant changes On 31 March 2013, China notified the World Health Organization (WHO) of the first recorded human infections with A(H7N9) virus. Poultry markets--which were rapidly identified as a major source of transmission of A(H7N9) to humans--were closed down in the affected areas. Surveillance in humans and poultry was heightened and technical guidelines were quickly updated and disseminated. The health authorities collaborated with WHO in risk assessments and risk communication. New cases were reported promptly and publicly. Lessons learnt The relevant infrastructures, surveillance systems and response capacity need to be strengthened in preparation for future emergencies caused by emerging or existing disease threats. Results of risk assessments and other data should be released promptly and publicly and such release should not jeopardize future publication of the data in scientific journals. Coordination between public health and veterinary services would be stronger during an emergency if these services had already undertaken joint preparedness planning. [ABSTRACT FROM AUTHOR]

Background. Glucocorticoids increase the risk of developing critical disease from viral infections. However, primary care practitioners in China use them as antipyretics, potentially exposing hundreds of millions to this risk. Methods. We enrolled all patients with confirmed pandemic influenza A (pH1N1) virus infection aged ⩾3 years with available medical records at 4 Shenyang City hospitals from 20 October to 30 November 2009. A critical patient was any confirmed, hospitalized pH1N1 patient who developed ⩾1 of the following: death, respiratory failure, septic shock, failure or insufficiency of ⩾2 nonpulmonary organs, mechanical ventilation, or ICU admission. In a retrospective cohort study, we evaluated the risk of developing critical illness in relation to early (⩽72 hours of influenza-like illness [ILI] onset) glucocorticoids treatment. Results. Of the 83 hospitalized case-patients, 46% developed critical illness, 17% died, and 37% recovered and were discharged. Critically ill and other patients did not differ by underlying conditions and severity, median temperature at first clinic visit, and other measured risk factors. Of 17 patients who received early glucocorticoid treatment, 71% subsequently developed critical disease compared with 39% of 66 patients who received late (>72 hours) or no glucocorticoid treatment (RRM-H 5 1.8, 95% CI 5 1.2-2.8, after adjusting for 2 summary variables; ie, presence of underlying diseases and presence of underlying risk factors). Proportional hazards modeling showed that use of glucocorticoids tripled the hazard of developing critical disease (hazard ratio [HR] 5 2.9, 95% CI 5 1.3-6.2, after adjusting for the same summary variables). Conclusions. Early use of parenteral glucocorticoids therapy for fever reduction and pneumonia prevention increases the risk for critical disease or death from pH1N1 infection. We recommend that guidelines on glucocorticoid use be established and enforced. [ABSTRACT FROM AUTHOR]

Background. In China, 30 human cases of avian influenza A (H5N1) virus infection were identified through July 2008. We conducted a retrospective case-control study to identify risk factors for influenza H5N1 disease in China. Methods. A questionnaire about potential influenza H5N1 exposures was administered to 28 patients with influenza H5N1 and to 134 randomly selected control subjects matched by age, sex, and location or to proxies. Conditional logistic regression analyses were performed. Results. Before their illness, patients living in urban areas had visited wet poultry markets, and patients living in rural areas had exposure to sick or dead backyard poultry. In multivariable analyses, independent risk factors for influenza H5N1 were direct contact with sick or dead poultry (odds ratio [OR], 506.6 [95% confidence interval {CI}, 15.7-16319.6]; P < .001), indirect exposure to sick or dead poultry (OR, 56.9 [95% CI, 4.3-745.6]; P = .002), and visiting a wet poultry market (OR, 15.4 [95% CI, 3.0-80.2]; P = .001). Conclusions. To prevent human influenza H5N1 in China, the level of education about avoiding direct or close exposures to sick or dead poultry should be increased, and interventions to prevent the spread of influenza H5N1 at live poultry markets should be implemented. [ABSTRACT FROM AUTHOR]