Q&A: What have we found out about the influenza A (H1N1) 2009 pandemic virus?

Q&A: What have we found out about the influenza A (H1N1) 2009 pandemic virus?

The 1918 pandemic influenza virus is said to have started by causing relatively mild disease in the summer but to have become more severe in the winter. Do we know why, and might influenza A (H1N1) 2009 do the same? It is not clear precisely what changes resulted in the increased severity of infection during the second wave of the 1918 Spanish influenza pandemic. Certainly the occurrence of mul...

The 2009 H1N1 Pandemic Influenza Virus: What Next?

History suggests that the 2009 pandemic H1N1 influenza virus faces extinction unless it mutates to avoid already high global population immunity. The immune escape mechanisms potentially at its disposal include antigenic drift, antigenic shift via genetic reassortment, and intrasubtypic reassortment. Going back to the late 19th century, the evolutionary histories of past pandemic viruses are ex...

2009 H1N1 Influenza Virus Seroepidemiology

Pandemic (H1N1) 2009 influenza.

On 11 June 2009, the World Health Organization declared the first human influenza pandemic since 1968–1969. The responsible virus, pandemic (H1N1) 2009 influenza, is a novel triple-reassortant influenza A virus, incorporating avian, swine and human influenza genes.1 The virus is resistant to the anti-influenza medications, amantadine and rimantadine, but is generally sensitive to the neuraminid...

Pandemic (H1N1) 2009 influenza vaccine roll-out in NSW.

The roll-out of the pandemic (H1N1) 2009 influenza vaccine in NSW was significantly different to that envisaged for a pandemic vaccination program. Pre-pandemic planning had focused on the urgent roll-out of a vaccine through mass vaccination clinics in a time of high demand due to a virulent influenza virus. Instead the situation was less urgent, with the vaccine available only after the peak ...