Two separate studies into the 2009 H1N1 Pandemic which examined in depth data collected in Norway and Kentucky have been published in the past week and BOTH identify a curious feature of the H1N1(2009) Swine Flu virus. These add to the growing number of studies all of which found that when this mutation on an H protein (D222G) occurred the virus seemed to replicate in the host at a greater rate.  So although the majority of cases were mild a few were very serious indeed and these were typically those that led to the death of an otherwise fit patient.  Clearly urgent research is needed to discover why this happens in some people and not others so that our prophylaxis can be more targetted.