Cross sectional survey of influenza antibodies before and during the 2009 pandemic in Shenzhen, China.
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ABSTRACT:
SUBMITTER: Wu CL
PROVIDER: S-EPMC3558489 | biostudies-literature | 2013
REPOSITORIES: biostudies-literature
Publications
Cross sectional survey of influenza antibodies before and during the 2009 pandemic in Shenzhen, China.
Wu Chun-Li CL Lu Juan J Wang Maggie Haitian MH Lv Xing X Chen Ying Y Kung Hsiang-fu HF Zee Benny B Cheng Xiao-wen XW He Ming-Liang ML He Ming-Liang ML
PloS one 20130129 1
Much information is available for the 2009 H1N1 influenza immunity response, but little is known about the antibody change in seasonal influenza before and during the novel influenza A pandemic. In this study, we conducted a cross-sectional serological survey of 4 types of major seasonal influenza in March and September 2009 on a full range of age groups, to investigate seasonal influenza immunity response before and during the outbreak of the sH1N1 influenza in Shenzhen - the largest migration ...[more]
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Project description:BackgroundSelf-diagnosis of influenza is an important component of pandemic control and management as it may support self-management practices and reduce visits to healthcare facilities, thus helping contain viral spread. However, little is known about the accuracy of self-diagnosis of influenza, particularly during pandemics.MethodsWe used cross-sectional survey data to correlate self-diagnosis of influenza with serological evidence of 2009 pandemic influenza A(H1N1) infection (haemagglutination inhibition titres of ?1:40) and to determine what symptoms were more likely to be present in accurate self-diagnosis. The sera and risk factor data were collected for the national A(H1N1) seroprevalence survey from November 2009 to March 2010, 3 months after the first pandemic wave in New Zealand (NZ).ResultsThe samples consisted of 318 children, 413 adults and 423 healthcare workers. The likelihood of being seropositive was no different in those who believed they had influenza from those who believed they did not have influenza in all groups. Among adults, 23.3% (95% CI 11.9% to 34.7%) of those who reported having had influenza were seropositive for H1N1, but among those reporting no influenza, 21.3% (95% CI 13% to 29.7%) were also seropositive. Those meeting NZ surveillance or Ministry of Health influenza case definitions were more likely to believe they had the flu (surveillance data adult sample OR 27.1, 95% CI 13.6 to 53.6), but these symptom profiles were not associated with a higher likelihood of H1N1 seropositivity (surveillance data adult sample OR 0.93, 95% CI 0.5 to 1.7).ConclusionsSelf-diagnosis does not accurately predict influenza seropositivity. The symptoms promoted by many public health campaigns are linked with self-diagnosis of influenza but not with seropositivity. These findings raise challenges for public health initiatives that depend on accurate self-diagnosis by members of the public and appropriate self-management action.
| S-EPMC3191601 | biostudies-literature
Project description:We investigated the first known outbreak of pandemic 2009 influenza A (H1N1) at a primary school in China.To describe epidemiologic findings, identify risk factors associated with 2009 H1N1 illness, and inform national policy including school outbreak control and surveillance strategies.We conducted retrospective case finding by reviewing the school's absentee log and retrieving medical records. Enhanced surveillance was implemented by requiring physicians to report any influenza-like illness (ILI) cases to public health authorities. A case-control study was conducted to detect potential risk factors for 2009 H1N1 illness. A questionnaire was administered to 50 confirmed cases and 197 age-, gender-, and location-matched controls randomly selected from student and population registries.The attack rate was 4% (50/1314), and children from all grades were affected. When compared with controls, confirmed cases were more likely to have been exposed to persons with respiratory illness either in the home or classroom within 7 days of symptom onset (OR, 4.5, 95% CI: 1.9-10.7). No cases reported travel or contact with persons who had traveled outside of the country.Findings in this outbreak investigation, including risk of illness associated with contacting persons with respiratory illness, are consistent with those reported by others for seasonal influenza and 2009 H1N1 outbreaks in school. The outbreak confirmed that community-level transmission of 2009 H1N1 virus was occurring in China and helped lead to changes in the national pandemic policy from containment to mitigation.
| S-EPMC4634656 | biostudies-other
Project description:Pre-existing antibodies to influenza virus neuraminidase may provide protection against infection influenza viruses containing novel hemagglutinin (HA). The aim of our study was to evaluate serum neuraminidase-inhibiting (NI) antibodies against А/California/07/2009(H1N1) [H1N1/2009pdm] and А/New Caledonia/20/1999(H1N1) [H1N1/1999] influenza viruses in relation with the age of participants and hemagglutination-inhibition (HI) antibody levels. Anti-H1N1/2009pdm neuraminidase and anti-H1N1/1999 neuraminidase antibody levels were measured in total 219 serum samples from Russian healthy peoples of various ages examined before and a year after pandemic strain appearance. We adjusted peroxidase-linked lectin micro-procedure to measure NI antibody titers using the reassortant A/H7N1 influenza viruses based on A/equine/Prague/1/56(H7N7). Also, HI antibody titers were estimated against H1N1/2009pdm, H1N1/1999 and a panel of seasonal A/H1N1 influenza viruses.In sera samples collected during the fall of 2010, mean titers of specific HI and NI antibodies to H1N1/2009pdm were 2-2.1 times lower than antibody levels against H1N1/1999. Of the 163 individuals examined, 58 (35.6%) had NI anti-H1N1/2009pdm antibody titers > 1:20, compared to 93 (57.1%) who had NI anti-H1N1/1999 antibody titers > 1:20. There were low correlations between HI and NI antibody levels against either H1N1/1999 or H1N1/2009pdm in the same serum samples. The 24 adults born between 1957 and 1977 expressed very low levels of NI antibodies to A/H1N1 influenza viruses. Persons with low HI anti-H1N1/2009pdm titers but positive to seasonal A/H1N1 demonstrated significantly higher NI anti-A/H1N1 antibody titers than unexposed subjects. In 2005 cross-reactive NI anti-H1N1/2009pdm antibody titers > 1:20 were detected among 7.1% of young people.Our study confirmed that contact with seasonal influenza viruses may have contributed to generating the cross-reacting anti-H1N1/2009pdm NI antibodies which were detected in the sera of 18-20 years old people examined before the pandemic virus active circulation. The lowest levels of antibodies to the neuraminidase of N1 subtype were in the group of participants born during the circulation of influenza A/H2N2 or A/H3N2 viruses. The low correlation between HI and NI antibody titers suggests that NI antibody detection can be used as an additional test to evaluate the immune response after influenza infections or immunizations.
| S-EPMC4399204 | biostudies-other
Project description:The 2009 pandemic H1N1 influenza pandemic demonstrated the global health threat of reassortant influenza strains. Herein, we report a detailed analysis of plasmablast and monoclonal antibody responses induced by pandemic H1N1 infection in humans. Unlike antibodies elicited by annual influenza vaccinations, most neutralizing antibodies induced by pandemic H1N1 infection were broadly cross-reactive against epitopes in the hemagglutinin (HA) stalk and head domain of multiple influenza strains. The antibodies were from cells that had undergone extensive affinity maturation. Based on these observations, we postulate that the plasmablasts producing these broadly neutralizing antibodies were predominantly derived from activated memory B cells specific for epitopes conserved in several influenza strains. Consequently, most neutralizing antibodies were broadly reactive against divergent H1N1 and H5N1 influenza strains. This suggests that a pan-influenza vaccine may be possible, given the right immunogen. Antibodies generated potently protected and rescued mice from lethal challenge with pandemic H1N1 or antigenically distinct influenza strains, making them excellent therapeutic candidates.
| S-EPMC3023136 | biostudies-literature
Project description:ObjectiveHypertension (HTN) is an important public health issue worldwide, associated with the rapid economic development and urbanisation over the last decades. This is especially the case in Shenzhen, which has benefited greatly from the reform and opening-up policies. However, there is limited information on the epidemiology of HTN in this region. This study was designed to investigate the prevalence, awareness, treatment and control of HTN and the associated factors among adult residents in Shenzhen, China.DesignPopulation-based, cross-sectional study.ParticipantsThrough the multistage stratified random sampling method, a representative sample of 10 043 urban population aged ≥18 years were selected. Three consecutive blood pressure (BP) readings were measured after resting for a 5 min seat by trained staff and HTN was defined as mean systolic BP ≥140 mm Hg and/or diastolic BP ≥90 mm Hg and/or self-reported current use of antihypertensive drugs. Participants were interviewed using a structured questionnaire. Anthropometric details, BP, blood and urine samples were also collected.Primary outcome measurePrevalence of HTN.ResultsOverall, the weighted prevalence of HTN among residents in Shenzhen was 19.2% (95% CI 18.5 to 20.0). Among patients with HTN, 55.0% (95% CI 52.9 to 57.1) were aware of their condition and 44.9% (95% CI 42.8 to 47.1) were taking antihypertensive medications, but only 21.7% (95% CI 20.0 to 23.5) achieved BP control. Among those who knew their HTN, 81.7% (95% CI 79.3 to 83.8) were under treatment and 48.3% (95% CI 45.1 to 51.5) were controlled among those with treated HTN. Male, older age, lower educational level, overweight and obesity, family history of HTN, tobacco smoking, alcohol intake, diabetes mellitus, dyslipidaemia and high uric acid were associated with HTN.ConclusionsHTN is a major public health concern in Shenzhen, which has low awareness, treatment and control rates, and is associated with several risk factors. Effective multifaceted implementation strategies are highly needed to combat the emerging burden of HTN.
| S-EPMC9214353 | biostudies-literature
Project description:The Internet hospital, an innovative approach to providing health care, is rapidly developing in China because it has the potential to provide widely accessible outpatient service delivery via Internet technologies. To date, China's Internet hospitals have not been systematically investigated.The aim of this study was to describe the characteristics of China's Internet hospitals, and to assess their health service capacity.We searched Baidu, the popular Chinese search engine, to identify Internet hospitals, using search terms such as "Internet hospital," "web hospital," or "cloud hospital." All Internet hospitals in mainland China were eligible for inclusion if they were officially registered. Our search was carried out until March 31, 2017.We identified 68 Internet hospitals, of which 43 have been put into use and 25 were under construction. Of the 43 established Internet hospitals, 13 (30%) were in the hospital informatization stage, 24 (56%) were in the Web ward stage, and 6 (14%) were in full Internet hospital stage. Patients accessed outpatient service delivery via website (74%, 32/43), app (42%, 18/43), or offline medical consultation facility (37%, 16/43) from the Internet hospital. Furthermore, 25 (58%) of the Internet hospitals asked doctors to deliver health services at a specific Web clinic, whereas 18 (42%) did not. The consulting methods included video chat (60%, 26/43), telephone (19%, 8/43), and graphic message (28%, 12/43); 13 (30%) Internet hospitals cannot be consulted online any more. Only 6 Internet hospitals were included in the coverage of health insurance. The median number of doctors available online was zero (interquartile range [IQR] 0 to 5; max 16,492). The median consultation fee per time was ¥20 (approximately US $2.90, IQR ¥0 to ¥200).Internet hospitals provide convenient outpatient service delivery. However, many of the Internet hospitals are not yet mature and are faced with various issues such as online doctor scarcity and the unavailability of health insurance coverage. China's Internet hospitals are heading in the right direction to improve provision of health services, but much more remains to be done.
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Project description:BACKGROUND:Mainland China experienced pandemic influenza H1N1 (2009) virus (pH1N1) with peak activity during November-December 2009. To understand the geographic extent, risk factors, and attack rate of pH1N1 infection in China we conducted a nationwide serological survey to determine the prevalence of antibodies to pH1N1. METHODOLOGY/PRINCIPAL FINDINGS:Stored serum samples (n?=?2,379) collected during 2006-2008 were used to estimate baseline serum reactogenicity to pH1N1. In January 2010, we used a multistage-stratified random sampling method to select 50,111 subjects who met eligibility criteria and collected serum samples and administered a standardized questionnaire. Antibody response to pH1N1 was measured using haemagglutination inhibition (HI) assay and the weighted seroprevalence was calculated using the Taylor series linearization method. Multivariable logistic regression analyses were used to examine risk factors for pH1N1 seropositivity. Baseline seroprevalence of pH1N1 antibody (HI titer ?40) was 1.2%. The weighted seroprevalence of pH1N1 among the Chinese population was 21.5%(vaccinated: 62.0%; unvaccinated: 17.1%). Among unvaccinated participants, those aged 6-15 years (32.9%) and 16-24 years (30.3%) had higher seroprevalence compared with participants aged 25-59 years (10.7%) and ?60 years (9.9%, P<0.0001). Children in kindergarten and students had higher odds of seropositivity than children in family care (OR: 1.36 and 2.05, respectively). We estimated that 207.7 million individuals (15.9%) experienced pH1N1 infection in China. CONCLUSIONS/SIGNIFICANCE:The Chinese population had low pre-existing immunity to pH1N1 and experienced a relatively high attack rate in 2009 of this virus. We recommend routine control measures such as vaccination to reduce transmission and spread of seasonal and pandemic influenza viruses.
| S-EPMC3080876 | biostudies-literature
Project description:In India, the first outbreak of pandemic influenza (H1N1) 2009 (H1N1pdm) was reported from Panchgani, Maharashtra, in June 2009. Studies from several countries have revealed different levels of pre-existing immunity to H1N1pdm 2009 in various age groups. This study was undertaken using age-stratified pre-pandemic human sera to understand baseline cross-reactivity of antibodies against H1N1pdm. Using cut off antibody titers 20 and 40, overall cross-reactivity was 2.1 and 0.9% respectively by microneutralization assay; 1.2% and 0.7% by haemagglutination inhibition assay, respectively. Results showed higher baseline antibodies and cross-reactive antibodies in the 0-19 age group whereas the elderly age group (?60) showed no cross-reactivity to H1N1pdm. The higher baseline and cross-reactive antibodies in 0-19 years age group could be because of higher positivity to seasonal H1N1 in that age group. Overall, low level of cross-reactive antibodies to H1N1pdm virus were found in humans in pre-pandemic period in Maharashtra, India.
| S-EPMC3550812 | biostudies-literature
Project description:BACKGROUND: In 2009, a novel influenza virus (2009 pandemic influenza A (H1N1) virus (pH1N1)) caused significant disease in the United States. Most states, including Florida, experienced a large fall wave of disease from September through November, after which disease activity decreased substantially. We determined the prevalence of antibodies due to the pH1N1 virus in Florida after influenza activity had peaked and estimated the proportion of the population infected with pH1N1 virus during the pandemic. METHODS: During November-December 2009, we collected leftover serum from a blood bank, a pediatric children's hospital and a pediatric outpatient clinic in Tampa Bay Florida. Serum was tested for pH1N1 virus antibodies using the hemagglutination-inhibition (HI) assay. HI titers ?40 were considered seropositive. We adjusted seroprevalence results to account for previously established HI assay specificity and sensitivity and employed a simple statistical model to estimate the proportion of seropositivity due to pH1N1 virus infection and vaccination. RESULTS: During the study time period, the overall seroprevalence in Tampa Bay, Florida was 25%, increasing to 30% after adjusting for HI assay sensitivity and specificity. We estimated that 5.9% of the population had vaccine-induced seropositivity while 25% had seropositivity secondary to pH1N1 virus infection. The highest cumulative incidence of pH1N1 virus infection was among children aged 5-17 years (53%) and young adults aged 18-24 years (47%), while adults aged ?50 years had the lowest cumulative incidence (11-13%) of pH1N1 virus infection. CONCLUSIONS: After the peak of the fall wave of the pandemic, an estimated one quarter of the Tampa Bay population had been infected with the pH1N1 virus. Consistent with epidemiologic trends observed during the pandemic, the highest burdens of disease were among school-aged children and young adults.
| S-EPMC3243696 | biostudies-literature
Project description:Data on risk factors for severe outcomes from 2009 pandemic influenza A (H1N1) virus infection are limited outside of developed countries.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).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.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.
| S-EPMC3060897 | biostudies-other