Comments on: Severe cases of pandemic influenza http://www.virology.ws/2009/10/21/severe-cases-of-pandemic-influenza/ About viruses and viral disease Mon, 22 Mar 2010 03:00:46 -0700 http://wordpress.org/?v=2.8.6 hourly 1 By: marcellopucciarelli http://www.virology.ws/2009/10/21/severe-cases-of-pandemic-influenza/comment-page-1/#comment-18269 marcellopucciarelli Tue, 03 Nov 2009 00:51:13 +0000 http://www.virology.ws/?p=2197#comment-18269 I wonder whether a mathematical model such as the one proposed by Mohtashemi and Levins (Transient dynamics and early diagnostics in infectious disease, J.Math.Biol. 2001) has found application in the study of severe illness caused by influenza. The model emphasizes the importance of the duration of the period of inactivity of the immune system after invasion: with increased duration of immune inactivity the pathogenic load increases exponentially, the peak of infection is reached earlier and the peak has a greater intensity.<br><br>It is a difficult paper (for me), and its equations are far beyond my understanding. It seems, however, that by feeding the model with appropriate parameters (e.g., reproductive rates, rates of induction of the immune system) it could be possible to get some insights about severe illness, even in cases where the specificity of action of the pathogen is poorly understood. I wonder whether a mathematical model such as the one proposed by Mohtashemi and Levins (Transient dynamics and early diagnostics in infectious disease, J.Math.Biol. 2001) has found application in the study of severe illness caused by influenza. The model emphasizes the importance of the duration of the period of inactivity of the immune system after invasion: with increased duration of immune inactivity the pathogenic load increases exponentially, the peak of infection is reached earlier and the peak has a greater intensity.

It is a difficult paper (for me), and its equations are far beyond my understanding. It seems, however, that by feeding the model with appropriate parameters (e.g., reproductive rates, rates of induction of the immune system) it could be possible to get some insights about severe illness, even in cases where the specificity of action of the pathogen is poorly understood.

]]> By: Marcello Pucciarelli http://www.virology.ws/2009/10/21/severe-cases-of-pandemic-influenza/comment-page-1/#comment-18268 Marcello Pucciarelli Tue, 03 Nov 2009 00:48:14 +0000 http://www.virology.ws/?p=2197#comment-18268 I wonder whether a mathematical model such as the one proposed by Mohtashemi and Levins (Transient dynamics and early diagnostics in infectious disease, J.Math.Biol. 2001) has found application in the study of severe illness caused by influenza. The model emphasizes the importance of the duration of the period of inactivity of the immune system after invasion: with increased duration of immune inactivity the pathogenic load increases exponentially, the peak of infection is reached earlier and the peak has a greater intensity.<br><br>It is a difficult paper (for me), and its equations are far beyond my understanding. It seems, however, that by feeding the model with appropriate parameters (e.g., reproductive rates, rates of induction of the immune system) it could be possible to get some insights about severe illness, even in cases where the specificity of action of the pathogen is poorly understood. I wonder whether a mathematical model such as the one proposed by Mohtashemi and Levins (Transient dynamics and early diagnostics in infectious disease, J.Math.Biol. 2001) has found application in the study of severe illness caused by influenza. The model emphasizes the importance of the duration of the period of inactivity of the immune system after invasion: with increased duration of immune inactivity the pathogenic load increases exponentially, the peak of infection is reached earlier and the peak has a greater intensity.

It is a difficult paper (for me), and its equations are far beyond my understanding. It seems, however, that by feeding the model with appropriate parameters (e.g., reproductive rates, rates of induction of the immune system) it could be possible to get some insights about severe illness, even in cases where the specificity of action of the pathogen is poorly understood.

]]> By: profvrr http://www.virology.ws/2009/10/21/severe-cases-of-pandemic-influenza/comment-page-1/#comment-18055 profvrr Mon, 26 Oct 2009 13:51:36 +0000 http://www.virology.ws/?p=2197#comment-18055 The H1N1 virus that disappeared in 1957 re-emerged in 1977. You might want to read the post "Origin of contemporary H1N1 influenza virus" at <a href="http://www.virology.ws/2009/03/02/origin-of-current-influenza-h1n1-virus/" rel="nofollow">http://www.virology.ws/2009/03/02/origin-of-cur...</a> for clarification. Influenza viruses that circulated in the 1940s are antigenically similar to the 2009 H1N1 virus and hence infection confers some protection. The H1N1 virus that disappeared in 1957 re-emerged in 1977. You might want to read the post “Origin of contemporary H1N1 influenza virus” at http://www.virology.ws/2009/03/02/origin-of-cur... for clarification. Influenza viruses that circulated in the 1940s are antigenically similar to the 2009 H1N1 virus and hence infection confers some protection.

]]> By: uberVU - social comments http://www.virology.ws/2009/10/21/severe-cases-of-pandemic-influenza/comment-page-1/#comment-18032 uberVU - social comments Sun, 25 Oct 2009 15:58:12 +0000 http://www.virology.ws/?p=2197#comment-18032 <strong>Social comments and analytics for this post...</strong> This post was mentioned on Twitter by profvrr: I blogged in response to your question @2pt7K @EpicBear re H1N1 virulence at http://bit.ly/1Np5Z9... Social comments and analytics for this post…

This post was mentioned on Twitter by profvrr: I blogged in response to your question @2pt7K @EpicBear re H1N1 virulence at http://bit.ly/1Np5Z9…

]]> By: himanshu_sharma http://www.virology.ws/2009/10/21/severe-cases-of-pandemic-influenza/comment-page-1/#comment-18023 himanshu_sharma Sun, 25 Oct 2009 04:15:38 +0000 http://www.virology.ws/?p=2197#comment-18023 "Transmission of the H1N1 virus in humans stopped in 1957 when the virus was replaced by the H2N2 strain. But the 1957 human H1N1 strain, which was reintroduced into people in 1977, is only distantly related to the 2009 swine-origin H1N1. If you were born before 1950, you have some protection against infection with the 2009 H1N1 strain."<br>From this I can understand that H1N1 was replaced by a less virulent H2N2 in 1957,but your very next statement that H1N1 was reintroduced into people in 1977,i didn't understand that.It should be H2N2(as it is has replaced H1N1) getting reintroduced into people in 1977.Also can you please elaborate more on how people born before1950 have a specific immunity towards 2009 swine flu virus? “Transmission of the H1N1 virus in humans stopped in 1957 when the virus was replaced by the H2N2 strain. But the 1957 human H1N1 strain, which was reintroduced into people in 1977, is only distantly related to the 2009 swine-origin H1N1. If you were born before 1950, you have some protection against infection with the 2009 H1N1 strain.”
From this I can understand that H1N1 was replaced by a less virulent H2N2 in 1957,but your very next statement that H1N1 was reintroduced into people in 1977,i didn't understand that.It should be H2N2(as it is has replaced H1N1) getting reintroduced into people in 1977.Also can you please elaborate more on how people born before1950 have a specific immunity towards 2009 swine flu virus?

]]> By: profvrr http://www.virology.ws/2009/10/21/severe-cases-of-pandemic-influenza/comment-page-1/#comment-17985 profvrr Fri, 23 Oct 2009 21:18:33 +0000 http://www.virology.ws/?p=2197#comment-17985 It's an issue of great controversy as you might imagine. There have<br>been a good number of epidemiological studies done on this issue and<br>most have found little or no benefit from immunizing the elderly. This<br>is not true for younger ages, though. The problem is that many of<br>these studies were not done properly, so a good one is needed.<br>Nevertheless, I don't think anyone would suggest that this age group<br>should not be immunized. The problem seems to be a poor immune<br>response in those over 65 years of age - so what we need is to develop<br>new approaches to stimulate immune responses in this age group. By the<br>way, most of the influenza mortality in non-pandemic years is due to<br>infections of the over-65 year old population; that's why they are<br>targeted for immunization. It's an issue of great controversy as you might imagine. There have
been a good number of epidemiological studies done on this issue and
most have found little or no benefit from immunizing the elderly. This
is not true for younger ages, though. The problem is that many of
these studies were not done properly, so a good one is needed.
Nevertheless, I don't think anyone would suggest that this age group
should not be immunized. The problem seems to be a poor immune
response in those over 65 years of age – so what we need is to develop
new approaches to stimulate immune responses in this age group. By the
way, most of the influenza mortality in non-pandemic years is due to
infections of the over-65 year old population; that's why they are
targeted for immunization.

]]> By: profvrr http://www.virology.ws/2009/10/21/severe-cases-of-pandemic-influenza/comment-page-1/#comment-17962 profvrr Fri, 23 Oct 2009 12:37:27 +0000 http://www.virology.ws/?p=2197#comment-17962 It's an issue of great controversy as you might imagine. There have<br>been a good number of epidemiological studies done on this issue and<br>most have found little or no benefit from immunizing the elderly. This<br>is not true for younger ages, though. The problem is that many of<br>these studies were not done properly, so a good one is needed.<br>Nevertheless, I don't think anyone would suggest that this age group<br>should not be immunized. The problem seems to be a poor immune<br>response in those over 65 years of age - so what we need is to develop<br>new approaches to stimulate immune responses in this age group. By the<br>way, most of the influenza mortality in non-pandemic years is due to<br>infections of the over-65 year old population; that's why they are<br>targeted for immunization. It's an issue of great controversy as you might imagine. There have
been a good number of epidemiological studies done on this issue and
most have found little or no benefit from immunizing the elderly. This
is not true for younger ages, though. The problem is that many of
these studies were not done properly, so a good one is needed.
Nevertheless, I don't think anyone would suggest that this age group
should not be immunized. The problem seems to be a poor immune
response in those over 65 years of age – so what we need is to develop
new approaches to stimulate immune responses in this age group. By the
way, most of the influenza mortality in non-pandemic years is due to
infections of the over-65 year old population; that's why they are
targeted for immunization.

]]> By: Chad http://www.virology.ws/2009/10/21/severe-cases-of-pandemic-influenza/comment-page-1/#comment-17927 Chad Wed, 21 Oct 2009 15:00:52 +0000 http://www.virology.ws/?p=2197#comment-17927 Hi Vincent, I was hoping you or anyone else could comment or make a new post with your thoughts on this article (link below) questioning the efficacy of the influenza vaccine. Based on the studies mentioned, it seems that overall the influenza vaccine has had no effect on mortality rates in groups most susceptible to flu. Thanks for your time!<br><br><a href="http://www.theatlantic.com/doc/200911/brownlee-h1n1" rel="nofollow">http://www.theatlantic.com/doc/200911/brownlee-...</a> Hi Vincent, I was hoping you or anyone else could comment or make a new post with your thoughts on this article (link below) questioning the efficacy of the influenza vaccine. Based on the studies mentioned, it seems that overall the influenza vaccine has had no effect on mortality rates in groups most susceptible to flu. Thanks for your time!

http://www.theatlantic.com/doc/200911/brownlee-...

]]> By: Severe cases of pandemic influenza | H1N1DEATHS.US http://www.virology.ws/2009/10/21/severe-cases-of-pandemic-influenza/comment-page-1/#comment-17923 Severe cases of pandemic influenza | H1N1DEATHS.US Wed, 21 Oct 2009 12:24:11 +0000 http://www.virology.ws/?p=2197#comment-17923 [...] failure and refractory shock have been the most common causes of death. .. More here: Severe cases of pandemic influenza Posted in h1n1 deaths. Tags: been-the-most, children-under, common-causes, frequent-cause, [...] [...] failure and refractory shock have been the most common causes of death. .. More here: Severe cases of pandemic influenza Posted in h1n1 deaths. Tags: been-the-most, children-under, common-causes, frequent-cause, [...]

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