FLU NEWS SCAN: Latitude and age as pH1N1 risk factors; FluMist shipments begin

Aug 3, 2012

In Brazil, pH1N1-associated mortality was lower near equator
Compared with temperate regions, tropical regions of the Southern Hemisphere may have been disproportionately less affected by the 2009 H1N1 flu pandemic, with climate playing a key role, according to a study published Aug 1 in PLoS One. The researchers examined laboratory-confirmed deaths and vital statistics mortality beyond prepandemic levels in Brazilian states from latitudes 5° north to 35° south. Brazil was chosen because of its relatively uniform healthcare, disease surveillance, immunization, and disease-mitigation practices. Increases overall in pneumonia/influenza deaths and respiratory disease deaths of 5.2% and 2.7%, respectively, were found during the pandemic, but mortality rates were progressively lower and of later onset in equatorial regions, where low or no difference from prepandemic mortality levels were apparent. The latitudinal gradient in pandemic-associated mortality was consistent even after controlling for factors thought to affect transmissibility, such as population density, age structure, and level of urbanization, pointing to environmental variables, chiefly climate, as key factors in pandemic-associated mortality. The authors suggest that their findings "indicate that the mortality burden of the 2009 pandemic in the Tropics may have been substantially lower than currently suggested."
Aug 1 PLoS One study

Study adds more data on age-related protection against 2009 pandemic flu
A study published yesterday in PLoS One adds more evidence that the risk of 2009 H1N1 pandemic influenza (pH1N1) illness declined with age and provides more details about the age-related pattern. The authors aggregated lab-confirmed pH1N1 case data from eight jurisdictions in seven countries and evaluated them for age-associated discontinuities in pH1N1 incidence. They identified a significant leveling off of the decline in risk among those who were about 45 to 50 years old in 2009 (born between about 1959 and 1964), followed by a sharp decline in risk in those up to their late 50s (born before 1957, when H1N1 disappeared for a time). The trend was more pronounced in hospitalized patients and in women. The authors say their findings are in broad agreement with previous studies and could be explained by several mechanisms, which are not mutually exclusive.
Aug 2 PLoS One study

MedImmune begins shipping FluMist
MedImmune announced yesterday that it had begun shipping FluMist, its nasal spray live attenuated influenza vaccine, for the 2012-13 flu season. In a press release, the company said it expects to make about 13 million doses of FluMist for the US market. Chris Ambrose, MD, MedImmune's senior director of medical and scientific affairs, said in the statement, "MedImmune is committed to continuing its collaboration with providers and the public health community to immunize eligible preschool- and school-age children, adolescents and adults up to age 49 against the flu as early as possible each year." MedImmune is the fourth of five companies that make flu vaccine for the US market to announce the start of shipments. The only one remaining is Merck, which market's CSL's Afluria vaccine. A company spokeswoman has told CIDRAP News that it is on track for meeting its delivery obligations. The five companies expect to make up to 149 million doses for the upcoming US flu season.
Aug 2 MedImmune press release
Aug 1 CIDRAP News story "Flu vaccine makers begin shipments for US market"

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