One mutation away from increased transmissibility

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H7N9: One mutation away from increased transmissibility

•    The hemagglutinin of H7N9 virus does not efficiently bind human receptors
•    A single residue change in receptor binding site increases binding to human receptors
•    Mutations on hemagglutinin may reduce the effectiveness of current H7 vaccines

 The advent of H7N9 in early 2013 is of concern for a number of reasons, including its capability to infect humans, the lack of clarity in the etiology of infection, and because the human population does not have pre-existing immunity to the H7 subtype.

 Earlier sequence analyses of H7N9 hemagglutinin (HA) point to amino acid changes that predicted human receptor binding and impinge on the antigenic characteristics of the HA.

 Here, we report that the H7N9 HA shows limited binding to human receptors; however, should a single amino acid mutation occur, this would result in structural changes within the receptor binding site that allow for extensive binding to human receptors present in the upper respiratory tract. 

 Furthermore, a subset of the H7N9 HA sequences demarcating coevolving amino acids appears to be in the antigenic regions of H7, which, in turn, could impact effectiveness of the current WHO-recommended prepandemic H7 vaccines.

 http://www.cell.com/abstract/S0092-8674%2813%2900640-5 - http://www.cell.com/abstract/S0092-8674%2813%2900640-5
And lets not forget H7N9's mutation rate is 8 Xs that of a normal flu virus.

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LOPPER Members Profile Send Private Message Find Members Posts Add to Buddy List Guest Group	Post Options Post Reply Quote LOPPER Thanks(0) Quote Reply Topic: One mutation away from increased transmissibility Posted: June 08 2013 at 10:33am
	H7N9: One mutation away from increased transmissibility • The hemagglutinin of H7N9 virus does not efficiently bind human receptors • A single residue change in receptor binding site increases binding to human receptors • Mutations on hemagglutinin may reduce the effectiveness of current H7 vaccines The advent of H7N9 in early 2013 is of concern for a number of reasons, including its capability to infect humans, the lack of clarity in the etiology of infection, and because the human population does not have pre-existing immunity to the H7 subtype. Earlier sequence analyses of H7N9 hemagglutinin (HA) point to amino acid changes that predicted human receptor binding and impinge on the antigenic characteristics of the HA. Here, we report that the H7N9 HA shows limited binding to human receptors; however, should a single amino acid mutation occur, this would result in structural changes within the receptor binding site that allow for extensive binding to human receptors present in the upper respiratory tract. Furthermore, a subset of the H7N9 HA sequences demarcating coevolving amino acids appears to be in the antigenic regions of H7, which, in turn, could impact effectiveness of the current WHO-recommended prepandemic H7 vaccines. http://www.cell.com/abstract/S0092-8674%2813%2900640-5 - http://www.cell.com/abstract/S0092-8674%2813%2900640-5 And lets not forget H7N9's mutation rate is 8 Xs that of a normal flu virus.

jacksdad Members Profile Send Private Message Find Members Posts Add to Buddy List Executive Admin Joined: September 08 2007 Location: San Diego Status: Offline Points: 47251	Post Options Post Reply Quote jacksdad Report Post Thanks(0) Quote Reply Posted: June 08 2013 at 10:46am
	"And lets not forget H7N9's mutation rate is 8 Xs that of a normal flu virus." That's why I still put H7N9 only slightly behind MERS in terms of it's pandemic potential at the moment. MERS has already achieved limited H2H and a staggering mortality rate (unles we're missing mild cases), but flu will always out-mutate coronaviruses, and H7N9 is doing it even faster.
	"Buy it cheap. Stack it deep" "Any community that fails to prepare, with the expectation that the federal government will come to the rescue, will be tragically wrong." Michael Leavitt, HHS Secretary.

LOPPER Members Profile Send Private Message Find Members Posts Add to Buddy List Guest Group	Post Options Post Reply Quote LOPPER Thanks(0) Quote Reply Posted: June 08 2013 at 10:51am
	In April they were saying it was 2 mutations away if I recall correctly.