Background and Aims: Vaccination is the most effective method to prevent influenza infection. Among the available vaccines, cold-adapted live-virus vaccines are suitable approach that have been produced and evaluated for recent years in few countries. The goal of this project was to derivate a cold adapted variant of the influenza A/New Caledonia/20/1999(H1N1). Materials and Methods: Influenza ...

Pandemic 2009 H1N1 influenza A virus (2009 H1N1) differs from H1N1 strains that circulated in the past 50 years, but resembles the A/New Jersey/1976 H1N1 strain used in the 1976 swine influenza vaccine. We investigated whether sera from persons immunized with the 1976 swine influenza or recent seasonal influenza vaccines, or both, neutralize 2009 H1N1. Using retroviral pseudovirions bearing hem...

As of May 19, 2009, a total of 5,469 confirmed or probable cases of human infection with a novel influenza A (H1N1) virus had been documented in 47 states and the District of Columbia. In addition, the virus had spread to 41 countries, with a total of 4,774 cases reported in countries outside the United States. Because producing a novel influenza A (H1N1) virus vaccine will take several months,...

BACKGROUND An age bias toward children and young adults has been reported for infection and hospitalizations with pandemic H1N1 influenza (A[H1N1]pdm) in the 2009 and 2010 influenza seasons in the Southern and Northern Hemispheres. Serological analysis of prepandemic samples has shown a higher incidence of cross-reactive antibodies to A(H1N1)pdm virus in older populations; conserved T cell epit...

BACKGROUND Limited data are available on disease characteristics and outcomes of children with 2009 pandemic influenza A(H1N1) virus infection (pandemic H1N1 influenza) who have required hospital admission. METHODS We reviewed the charts of 58 children with pandemic H1N1 influenza admitted to a large pediatric hospital in Ontario, Canada, between May 8 and July 22, 2009. We compared risk fact...

The adaptive evolution of the hemagglutinin (HA) segment of the human influenza H1N1 and H3N2 viruses is not well understood due to antigenic mutations under selection pressures. This paper identified significant antigenic selection sites and discussed the structural relevance of these mutations. We discovered four positively selected sites for H1N1 (position 206 for the 1A lineage - 2009 swine...

The spring of 2009 witnessed the emergence of a novel influenza A(H1N1) virus resulting in the first influenza pandemic since 1968. In autumn of 2010, the 2009 novel H1N1 influenza strain re-emerged. We performed a retrospective time-series analysis of all patients with laboratory-confirmed H1N1 influenza who presented to our institution during 2009. Cases of influenza were assembled into 3-day...

Background Pandemic influenza H1N1/09 emerged in April 2009 and spread widely in Australia and New Zealand. Although an unprecedented number of cases required intensive care, comparative community-based studies with seasonal influenza strains have not shown any significant differences in clinical symptoms or severity. Methods The authors performed active surveillance on confirmed influenza-rel...

PURPOSE The purpose of this article is to describe the clinical and epidemiologic features and outcomes among children hospitalized with pandemic influenza A/H1N1 2009 infection. METHODS We retrospectively reviewed the charts of hospitalized pediatric patients (<18 years) diagnosed with pandemic influenza A/H1N1 2009 infection by reverse-transcriptase polymerase chain reaction at a tertiary h...

BACKGROUND Pregnant women are a high-risk group for morbidity and mortality from influenza. During the current pandemic of H1N1 influenza, few cases of H1N1 have been reported in pregnancy. CASES We report two cases of H1N1 influenza which occurred in single institution in the course of one month. The first patient developed acute respiratory distress syndrome, required intubation, and eventu...