Demographic shift of influenza A(H1N1)pdm09 during and after pandemic, rural India.
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ABSTRACT:
SUBMITTER: Broor S
PROVIDER: S-EPMC3437708 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Data on influenza illness rates with population denominators are needed to quantify overall morbidity and to prioritize public health intervention strategies.The rates of influenza A(H1N1)pdm09 infection during pandemic phases were determined in a longitudinal community cohort study as part of an influenza vaccine study in a rural community of North India.During the 711,731 person-weeks of surveillance, a total of 1410/7571 (19%) febrile acute respiratory illness cases were positive for influenza. Of these, 749 (53%) were influenza A(H1N1)pdm09, 643 (46%) influenza B, and 18 (1%) influenza A (H3N2). The overall incidence rate of influenza-associated febrile acute respiratory illness was 128/1000 person-years. The incidence rates of influenza A(H1N1)pdm09 were high during both the pandemic phase (179/1000 person-years; November 2009 to January 2010) and post-pandemic phase (156/1000 person-years; August to October 2010), with children<18 years of age being at the greatest risk of influenza infection in the community.These findings provide important information for planning clinical and public health intervention strategies to mitigate the impact of influenza epidemics.
| S-EPMC5733120 | biostudies-literature
Project description:The 2009 H1N1 influenza A virus that has targeted not only those with chronic medical illness, the very young and old, but also a large segment of the patient population that has previously been afforded relative protection - those who are young, generally healthy, and immune naive. The illness is mild in most, but results in hospitalization and severe ARDS in an important minority. Among those who become critically ill, 20-40% will die, predominantly of severe hypoxic respiratory failure. However, and potentially in part due to the young age of those affected, intensive care with aggressive oxygenation support will allow most people to recover. The volume of patients infected and with critical illness placed substantial strain on the capacity of the health care system and critical care most specifically. Despite this, the 2009 pandemic has engaged our specialty and highlighted its importance like no other. Thus far, the national and global critical care response has been brisk, collaborative and helpful - not only for this pandemic, but for subsequent challenges in years ahead.
| S-EPMC3256529 | biostudies-other
Project description:In 2009, Thailand experienced rapid spread of the pandemic influenza A(H1N1)pdm09 virus. The national response came under intense public scrutiny as the number of confirmed cases and associated deaths increased. Thus, during July-December 2009, the Ministry of Public Health and the World Health Organization jointly reviewed the response efforts. The review found that the actions taken were largely appropriate and proportionate to need. However, areas needing improvement were surveillance, laboratory capacity, hospital infection control and surge capacity, coordination and monitoring of guidelines for clinical management and nonpharmaceutical interventions, risk communications, and addressing vulnerabilities of non-Thai displaced and migrant populations. The experience in Thailand may be applicable to other countries and settings, and the lessons learned may help strengthen responses to other pandemics or comparable prolonged public health emergencies.
| S-EPMC3376790 | biostudies-literature
Project description:Previous influenza pandemics had second and on occasion third waves in many countries that were at times more severe than the initial pandemic waves.This study aims to determine the seroepidemiology of successive waves of H1N1pdm09 infections in Singapore and the overall risks of infection.We performed a cohort study amongst 838 adults, with blood samples provided upon recruitment and at 5 points from 2009 to 2011 and tested by haemagglutination inhibition (HI) with A/California/7/2009 (H1N1pdm09). Surveys on key demographic and clinical information were conducted at regular intervals, and associations between seroconversion and these variables were investigated.After the initial wave from June to September 2009, second and third waves occurred from November 2009 to February 2010 and April to June 2010, respectively. Seroconversion was 13·5% during the first wave and decreased to 6·2% and 6·8% in subsequent waves. Across the three waves, the elderly and those with higher starting HI titres were at lower risk of seroconversion, while those with larger households were at greater risk. Those with higher starting HI titres were also less likely to have an acute respiratory infection.The second and third waves in Singapore had lower serological attack rates than the first wave. The elderly and those with higher HI titres had lower risk, while those in larger households had higher risk of seroconversion.
| S-EPMC4634269 | biostudies-other
Project description:During August 2009-July 2010, we conducted 7 longitudinal telephone surveys among 503 adults in Hong Kong, China, to explore changes in their behavioral and psychological responses to the influenza A(H1N1)pdm09 virus epidemic. Trends were examined using generalized estimating equations models. Findings showed that responses varied with the course of the pandemic.
| S-EPMC5403031 | biostudies-literature
Project description:The prevalence and timing of emergence of oseltamivir-resistant seasonal and pandemic influenza A (H1N1) viruses in Myanmar in 2008 and 2009 are described in this report. In 2008, the oseltamivir-resistant seasonal H1N1 virus was detected at a lower rate (6%) and emerged at least 2 months later when compared with neighboring countries. Similarly, the prevalence of pandemic H1N1 virus was low (3%) and the timing of emergence was late (August 2009) in Myanmar. Interestingly, we detected three isolates that were resistant to both amantadine and oseltamivir. Limited movement of people into the country is attributed to the delayed emergence of drug-resistant seasonal and pandemic A(H1N1) viruses.
| S-EPMC5781210 | biostudies-literature
Project description:BackgroundThe transmission of influenza viruses occurs person to person and is facilitated by contacts within enclosed environments such as households. The aim of this study was to evaluate secondary attack rates and factors associated with household transmission of laboratory-confirmed influenza A(H1N1)pdm09 in the pandemic and post-pandemic seasons.MethodsDuring the 2009-2010 and 2010-2011 influenza seasons, 76 sentinel physicians in Navarra, Spain, took nasopharyngeal and pharyngeal swabs from patients diagnosed with influenza-like illness. A trained nurse telephoned households of those patients who were laboratory-confirmed for influenza A(H1N1)pdm09 to ask about the symptoms, risk factors and vaccination status of each household member.ResultsIn the 405 households with a patient laboratory-confirmed for influenza A(H1N1)pdm09, 977 susceptible contacts were identified; 16% of them (95% CI 14-19%) presented influenza-like illness and were considered as secondary cases. The secondary attack rate was 14% in 2009-2010 and 19% in the 2010-2011 season (p=0.049), an increase that mainly affected persons with major chronic conditions. In the multivariate logistic regression analysis, the risk of being a secondary case was higher in the 2010-2011 season than in the 2009-2010 season (adjusted odds ratio: 1.72; 95% CI 1.17-2.54), and in children under 5 years, with a decreasing risk in older contacts. Influenza vaccination was associated with lesser incidence of influenza-like illness near to statistical significance (adjusted odds ratio: 0.29; 95% CI 0.08-1.03).ConclusionThe secondary attack rate in households was higher in the second season than in the first pandemic season. Children had a greater risk of infection. Preventive measures should be maintained in the second pandemic season, especially in high-risk persons.
| S-EPMC4177918 | biostudies-literature
Project description:We report here the whole-genome sequence of six clinical isolates of influenza A(H1N1)pdm09, isolated from Kerala, India. Amino acid analysis of all gene segments from the A(H1N1)pdm09 isolates obtained in 2014 and 2015 identified several new mutations compared to the 2009 A(H1N1) pandemic strain.
| S-EPMC5511911 | biostudies-literature
Project description:In 2015, the swine derived A(H1N1)pdm09 pandemic strain outbreak became widespread throughout the different states of India. The reported cases and deaths in 2015 surpassed the previous years with more than 39000 laboratory confirmed cases and a death toll of more than 2500 people. There are relatively limited complete genetic sequences available for this virus from Asian countries. In this study, we describe the full genome analysis of influenza 2015 A(H1N1)pdm09 viruses isolated from West Bengal between January through December 2015. The phylogenetic analysis of the haemagglutinin sequence revealed clustering with globally circulating strains of genogroup 6B. This was further confirmed by the constructed concatenated tree using all eight complete gene segments of Kolkata A(H1N1)pdm09 isolates with the other strains from different timeline and lineages. A study from Massachusetts Institute of Technology (MIT) in 2015 reported novel mutations T200A and D225N in haemagglutinin gene of a 2014 Indian strain (A/India/6427/2014). However, in all the pandemic strains of 2014-2015 reported from India, so far including A(H1N1)pdm09 strains from Kolkata, D225N mutation was not observed, though the T200A mutation was found to be conserved. Neuraminidase gene of the analyzed strains did not show any oseltamivir resistant mutation H275Y suggesting continuation of Tamiflu® as drug of choice. The amino acid sequences of the all gene segments from 2015 A(H1N1)pdm09 isolates identified several new mutations compared to the 2009 A(H1N1)pdm09 strains, which may have contributed towards enhanced virulence, compared to 2009 A(H1N1)pdm09 strains.
| S-EPMC5172622 | biostudies-literature
Project description:When novel influenza viruses cause human infections, it is critical to characterize the illnesses, viruses, and immune responses to infection in order to develop diagnostics, treatments, and vaccines. The objective of the study was to collect samples from patients with suspected or confirmed A(H1N1)pdm09 infections that could be made available to the scientific community. Respiratory secretions, sera and peripheral blood mononuclear cells (PBMCs) were collected sequentially (when possible) from patients presenting with suspected or previously confirmed A(H1N1)pdm09 infections. Clinical manifestations and illness outcomes were assessed. Respiratory secretions were tested for the presence of A(H1N1)pdm09 virus by means of isolation in tissue culture and real time RT-PCR. Sera were tested for the presence and level of HAI and neutralizing antibodies against the A(H1N1)pdm09 virus.Thirty patients with confirmed A(H1N1)pdm09 infection were enrolled at Baylor College of Medicine (BCM). Clinical manifestations of illness were consistent with typical influenza. Twenty-eight of 30 had virological confirmation of illness; all recovered fully. Most patients had serum antibody responses or high levels of antibody in convalescent samples. Virus-positive samples were sent to J. Craig Venter Institute for sequencing and sequences were deposited in GenBank. Large volumes of sera collected from 2 convalescent adults were used to standardize antibody assays; aliquots of these sera are available from the repository. Aliquots of serum, PBMCs and stool collected from BCM subjects and subjects enrolled at other study sites are available for use by the scientific community, upon request.
| S-EPMC3651415 | biostudies-literature