Levels of preexisting antibodies to the hemagglutinin of pandemic influenza A(H1N1) 2009 (hereafter pandemic H1N1) virus positively correlate with age. The impact of contemporary seasonal influenza vaccines on establishing immunity to other pandemic H1N1 proteins is unknown. We measured serum antibodies to the neuraminidase (NA) of pandemic H1N1 in adults prior to and after vaccination with sea...

conclusions this case highlights the potential severity of h1n1 infections and the utility of considering cardiac tamponade in patients presenting with influenza symptoms and circulatory collapse. case presentation we describe a case of a young female with no prior cardiovascular history who presents with a pericardial effusion and shock secondary to cardiac tamponade from pericarditis due to h...

Pandemic H1N1/2009 influenza virus, derived from a reassortment of avian, human, and swine influenza viruses, possesses a unique gene segment combination that had not been detected previously in animal and human populations. Whether such a gene combination could result in the pathogenicity and transmission as H1N1/2009 virus remains unclear. In the present study, we used reverse genetics to con...

BACKGROUND Our aim was to determine the clinical and epidemiological features of pandemic influenza A/H1N1 in immunocompromised children with solid tumors and hematological malignancies. PATIENTS AND METHODS A prospective study was conducted during the H1N1 pandemic between August 2009 and February 2010 in a pediatric hematology-oncology unit. Demographic and clinical data were obtained from ...

BACKGROUND In Spring 2009, a novel reassortant strain of H1N1 influenza A emerged as a lineage distinct from seasonal H1N1. On June 11, the World Heath Organization declared a pandemic - the first since 1968. There are currently two main branches of H1N1 circulating in humans, a seasonal branch and a pandemic branch. The primary treatment method for pandemic and seasonal H1N1 is the antiviral d...

The live-attenuated influenza vaccine (LAIV) has generally been more efficacious than the inactivated vaccine in children. However, LAIV is not recommended for HIV-infected children because of insufficient data. We compared cellular, humoral, and mucosal immune responses to the 2013-2014 LAIV quadrivalent (LAIV4) in HIV-infected and uninfected children 2-25 years of age (yoa). We analyzed the r...

BACKGROUND In 2009, pandemic H1N1 influenza virus (2009 H1N1) emerged worldwide, causing morbidity and mortality that disproportionately affected young adults. Upper respiratory infection (URI), largely due to adenovirus, is an endemic cause of morbidity in military training. Whether clinical presentations differ or excess morbidity results from coinfection is unclear. METHODS The Center for ...

BACKGROUND Pandemic influenza A(H1N1)pdm09 emerged in Thailand in 2009. A prospective longitudinal adult cohort and household transmission study of influenza-like illness (ILI) was ongoing in rural Thailand at the time of emergence. Symptomatic and subclinical A(H1N1)pdm09 infection rates in the cohort and among household members were evaluated. METHODS A cohort of 800 Thai adults underwent a...

Since emergence of the pandemic (H1N1) 2009 virus in April 2009, three influenza A viruses-seasonal (H3N2), seasonal (H1N1), and pandemic (H1N1) 2009-have circulated in humans. Genetic reassortment between these viruses could result in enhanced pathogenicity. We compared 4 reassortant viruses with favorable in vitro replication properties with the wild-type pandemic (H1N1) 2009 virus with respe...

BACKGROUND The purpose of the present retrospective study was to examine the clinical differences between patients hospitalized with H1N1 virus and those hospitalized with nonvirus respiratory tract infection in 2009 and 2010. METHODS Adult patient data were collected from three tertiary hospital centers. Real-time reverse transcriptase polymerase chain reaction testing was used to confirm th...