Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

[Laidback Al]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

--->@MarionKoopmans --->@Crof A yesterday chinese paper doi: 10.1007/s11434-013-5880-5
suggested high degree of panic among readers.What's your op?

@MarionKoopmans ---> @ironorehopper --->@Crof

''i do not see new info in the paper, prediction is speculation. The severity score is quite crude and influenced by CFR ''

09:06 AM - 30 Apr 13

Individuals who die from this infections are hospitalized between 2 and 31 days before dying, with an average hospital stay of 9 days before death. Beside the few mild and one asymptomatic case, recovered patients are hospitalized for long periods too, from 6 to 25 days. That suggests this is a severe disease to me. The concern should be on whether or not this virus becomes transmissible.
<object style="position:absolute;z-index:1000" type="application/x-dgnria" id="plugin0" height="0" width="0">

</object>

 

[Giuseppe]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

I understand but look at who wrote this paper: The Ministry of Agriculture of China. A very interesting development.

This piece of paper is not the holy bible of pandemic risk assessment.

It is bad written, without evidences and proof and it is hardly all but a statement.

Furthermore, the Authors said that human cases detected so far are the 'tip of an iceberg'. How can they calculate actual cfr when the iceberg size is not determined?

And if there are so many cases, why does the overall situation not point toward a widespread workpalces abseenteism or school closures, mass burials?

Because if the cfr is really 20% and the iceberg is growing, than we must have mass burials or cremations...

 

[Pathfinder]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

Vincent Racaniello:

"For the most part we do not know the significance of any of the amino acid changes for viral replication and virulence in humans.

I believe that these H7N9 viruses might take one of two pathways. If they are widespread in birds, they could spread globally and cause sporadic zoonotic infections, as does avian influenza H5N1 virus. Alternatively, the H7N9 viruses could cause a pandemic. Influenza H7N9 virus infections have not occurred before in humans, so nearly everyone on the planet is likely susceptible to infection. Global spread of the virus would require human to human transmission, which has not been observed so far. Some human to human transmission of avian H7N7 influenza viruses was observed during an outbreak in 2003 in the Netherlands, but those viruses were different from the ones isolated recently in China. Whether or not these viruses will acquire the ability to transmit among humans by aerosol is unknown and cannot be predicted. If a variant of H7N9 virus that can spread among humans arises during replication in birds or humans, it might not have a chance encounter with a human, or if it did, it might not have the fitness to spread extensively.

What also tempers my concern about these H7N9 viruses is the fact that the last influenza pandemic (H1N1 virus) took place in 2009. No influenza pandemics in modern history are known to have taken place 4 years apart, although only 11 years separated the 1957 (H2N2) and 1968 (H3N2) pandemics. I suppose that is not much consolation, as there are always exceptions, especially when it comes to viruses."
...
http://www.virology.ws/2013/04/16/avian-influenza-h7n9-viruses-isolated-from-humans-what-do-the-gene-sequences-mean/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+VirologyBlog+(virology+blog

 

[gsgs]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

when people don't want to predict, they say it can't be predicted.
Or "noone can predict it" or "noone can predict it with any certainety"
And then come the people who _do_ predict, lol.
Everyone can predict. Predicting is easy. What it's worth
and what predictions we should trust how much - well, that's another question.
But any prediction is better than no prediction.

 

[JimO]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

I agree with Giuseppe that the paper is lacking scientifically and despite the qualifications of the authors, this is all highly speculative given what we know so far. However, even if their methods are not sound, that doesn't mean that they haven't speculated correctly. As I've stated elsewhere, the CFR calculated based on the reported cases is a gross overestimate, IMO. There most certainly appear to be many more mild cases circulating, which is hinted at based on the asymptomatic case in Bejing and the reduction of the calculated CFR as more cases are confirmed.

However, the sequences reveal that this virus has already adapted when comparing the bird sequences with human. Nobody can predict the rate or direction of future mutations, but we have a somewhat aggressive, adaptable virus that has a potential host pool of over 6 billion individual who have little or no immulogical protection. It makes sense that it will adapt to exploit this. Although it's still too early to really compare it to H5N1, there are some prominent differences:

1) Reported cases show a pattern from an origin (Shanghai) outward that has not abated.
2) The animal host has not been identified, whereas infected domestic poultry has been closely associated with human H5N1 cases.
3) There is clearer evidence of H2H spread than with H5N1.
4) Research has shown that H7 viruses can infect mammals other than humans and swine without much mutational change, such as mice. Based on the papers I've reviewed, it appears that H7 viruses can do this more readily than H5N1.

Personally, I think we could see a Pandemic as early as this fall in the northern hemisphere.

 

[Giuseppe]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

I think it could be useful to track the H1pdm09 and H3N2 seasonal flu virus activity in the same region H7N9 arisen.

The viral interference between these viruses may explain something else and perhaps may pave the way to a better understand of future events.

If the A.D.E. is really functioning, what would be the impact of concurrent H1pdm09 and H3N2 in the fall?

Have H7N9 arisen in H1pdm09 stricken area or not?

Dynamic maps could help.

 

[Hogweed]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

Has this paper had any discussion - http://link.springer.com/article/10.1007/s11434-013-5873-4

Chinese Science Bulletin
April 2013

Isolation and characterization of H7N9 viruses from live poultry markets?Implication of the source of current H7N9 infection in humans

The novel features that the new H7N9 viruses possess, including: previously unidentified HA and NA composition wide prevalence in avian hosts and the environment; an exceptional adaptive ability in humans; and the potential to acquire multiple basic amino acids at the HA cleavage site and evolve into a highly pathogenic form, are a major cause for concern with respect to public health worldwide.

Full PDF at link

 

[Shannon Bennett]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

There are no mass burials because transmission between humans is not sustained. We have had limited h2h transmissions but they stopped at one or two persons. We have some hints that health care providers have also been infected. Again, the number of subsequently infected were extremely low. The key here is if the virus can be limited in its ability infect any humans. That is why the Chinese closed the wet markets. Every human infection invites polymorphisms which affect the viruses ability to replicate in humans. Natural selection will favor those polymorphisms. Will we see these polymorphisms? I don't know. But I do agree with the authors of this paper that limiting human infection is key. Closing the wet markets may have been responsible for the lower number of cases in China over the last few days. But, despite the best efforts of the Chinese we still do not know what infected those who never had any contact with poultry or wet markets. Until we know the vector we are going to see additional cases. Given the unalterable fact that there have been at least 129 human cases in a few months whatever is responsible has to be over a very wide area and has to be able to infect at least some humans casually. Either that or it is so ubiquitous in the area that many thousands of people have been exposed and only a tiny fraction have become ill. Neither scenario is good.

 

[Laidback Al]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

. . . Given the unalterable fact that there have been at least 129 human cases in a few months whatever is responsible has to be over a very wide area and has to be able to infect at least some humans casually. Either that or it is so ubiquitous in the area that many thousands of people have been exposed and only a tiny fraction have become ill. Neither scenario is good.

Shannon has framed the issue we should all be concerned about. Even if it is ubiquitous in China, at some point it may start infecting people on other continents, where it is mostly certainly not ubiquitous now.

 

[Giuseppe]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

A just mBio online paper about NCoV but also for therapeuticals avenue for this new H7N9: Xhttp://mbio.asm.org/content/4/3/e00165-13.full.pdf+html

 

[Catbird]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

...And if there are so many cases, why does the overall situation not point toward a widespread workpalces abseenteism or school closures, mass burials?

Because if the cfr is really 20% and the iceberg is growing, than we must have mass burials or cremations...

How do you know that there isn't an increase in absenteeism in work places or schools? The only information source for such statistics is the Chinese government. The rest of the world is only informed about such matters via state controlled agencies and media. People who aren't Chinese citizens who live there, and who may have access to such information even if it's only anecdotal, are constrained by the knowledge that they are guests of a government who can tell them to leave at any time.

Objective, verifiable facts about what impact this outbreak is having on China's social or economic activities are simply not available. The lack of reports about absenteeism doesn't necessarily mean that there hasn't been an increase. It just means that we don't know if there has been an increase or not.

 

[Laidback Al]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

Vincent Racaniello:

. . . . What also tempers my concern about these H7N9 viruses is the fact that the last influenza pandemic (H1N1 virus) took place in 2009. No influenza pandemics in modern history are known to have taken place 4 years apart, although only 11 years separated the 1957 (H2N2) and 1968 (H3N2) pandemics. I suppose that is not much consolation, as there are always exceptions, especially when it comes to viruses."
...

I find this comment surprising from Dr. Racaniello. It seems to based on a presumption that because it hasn't happen yet, it won't happen in the future. While it is true that pandemics have a cyclical periodicity based on modern recorded history, the cause for the cyclical occurrence is unclear.

In an article by Taubenberger and Morens, Pandemic influenza – including a risk assessment of H5N1, they state:

Application of the criteria listed above to the available historical information suggests that there may have been at least 13 pandemics over the past 500 years (1509 to 2009), or approximately one pandemic every 38 years. These pandemics may not have occurred randomly. Whether or not there has been clustering of pandemics, there is evidence that some (but not all) pandemics have been followed by periods of high respiratory disease activity, which were associated with large outbreaks and high mortality, over a number of years. It may thus be helpful to think not only about pandemics as events that occur at specific points in time, but to consider also the occurrence of ‘pandemic eras’.

For example, the 90 years since 1918 can be said to comprise a pandemic era, because all of the influenza A viruses circulating since that time, up to the present, are descendants of the 1918 virus, and because seasonal influenza activity has been detected continuously during that period. Yet clearly in that interval there have been three (depending on how one defines the H1N1 recurrence in 1977, see below) or four pandemics.

We could be entering a new pandemic era if A(H7N9) or A(H5N1) becomes a pandemic strain. If so, there is no reason to believe that there needs to be a 38-year hiatus between pandemic eras.

 

[curiosity]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

Vincent Racaniello:

"What also tempers my concern about these H7N9 viruses is the fact that the last influenza pandemic (H1N1 virus) took place in 2009. No influenza pandemics in modern history are known to have taken place 4 years apart, although only 11 years separated the 1957 (H2N2) and 1968 (H3N2) pandemics. I suppose that is not much consolation, as there are always exceptions, especially when it comes to viruses."
...
http://www.virology.ws/2013/04/16/avian-influenza-h7n9-viruses-isolated-from-humans-what-do-the-gene-sequences-mean/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+VirologyBlog+(virology+blog

A few thoughts about "pandemic" intervals:

Without knowing a re-assorted virus created illness in 2009 - would it have been historically referenced as a Pandemic? Was the disease severe enough to have created so much interest the historians would have documented as such? Compared to diseases that routinely took out populations every year (particularly those under 5), IMO, H1N1pdm might have been noticed as a seasonal flu.

Population now is different than past pandemic events - perhaps increasing population = decreasing pandemic intervals = natural homeostasis, aka, balancing out the population.

Host competition between influenza viruses? - we know, we have seen, that although people are susceptible to more than one influenza virus - there is typically a dominant strain. Why don't susceptible people get sick twice in a year with BOTH circulating strains?

What if the population susceptibility to seasonal flu strains decreases so much because of consistent runs of the same virus that there are not enough people ill with seasonal influenza and a new strain now has the ability to get into the population without being the "fittest" , dominant virus? (What did China's flu season look like this year?)

 

[Giuseppe]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

I think that H1pdm09 - although mild in its overall clinical presentation - was a game-changer: after its emersion, a lot of new reassortants appeared in different places, and one of the most fit was surely the H3N2v, that is circulating currently in the US pigs population.

H1pdm09 is parenting H1, H3 swine viruses and it is not said that it could interact with other flu strains too.

China has seen a lot of H1pdm09 acitivity this year, for this reason I suggest a comparison between H1pdm09 circulation areas and H7N9 emersion.

Conversely, in the US H3N2 caused a severe season for not fully understood reasons.

Further, the H3N2 was not replaced by H1pdm09 at all.

In some weeks, Southern China regions should see the start of summer flu season: what will be the interference between H3, H1pdm09 and the new H7N9?

 

[curiosity]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

Further, the H3N2 was not replaced by H1pdm09 at all.

I agree, H1pdm09 was a game changer, and in the long term, did not replace H3N2 - except for one season.



After the first season, both viruses, in North America specifically, were detected frequently. Even this year, although H3N2 dominated, H1pdm09 was still detected with frequency.

 

[JimO]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

A few thoughts about "pandemic" intervals:

Without knowing a re-assorted virus created illness in 2009 - would it have been historically referenced as a Pandemic? Was the disease severe enough to have created so much interest the historians would have documented as such? Compared to diseases that routinely took out populations every year (particularly those under 5), IMO, H1N1pdm might have been noticed as a seasonal flu.

Population now is different than past pandemic events - perhaps increasing population = decreasing pandemic intervals = natural homeostasis, aka, balancing out the population.

Host competition between influenza viruses? - we know, we have seen, that although people are susceptible to more than one influenza virus - there is typically a dominant strain. Why don't susceptible people get sick twice in a year with BOTH circulating strains?

What if the population susceptibility to seasonal flu strains decreases so much because of consistent runs of the same virus that there are not enough people ill with seasonal influenza and a new strain now has the ability to get into the population without being the "fittest" , dominant virus? (What did China's flu season look like this year?)

All excellent points. You are probably right about calling the pdmH1N1 a true pandemic if compared with criteria used in decades past. It might have been viewed as a bad flu season, but might not have been recognized as a pandemic.

 

[AlaskaDenise]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

Isn't it really odd that Ministry of Agriculture scientists have published a paper about a disease which is NOT in animals (except a couple of pigeons)?

Something is really off here.

They have worked with USAID and FAO on HPAI. See: http://www.fao.org/docrep/017/ap388e/ap388e.pdf


.

 

[gsgs]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

while summer flu outbreaks were common centuries ago,
In a situation as in 2009 with normal seasonal winter flus in USA
and Europe for the previous 40 years
they would have probably noticed the unusual spread of ******
from America all around the world starting in ~May in NY
and yes, they would have considered it a pandemic, although a mild one.
Its quick spread around the world was obvious.

If there were some sort of barrier, that prevents consecutive pandemics
in less than x-years, then you would have to ask, what the reason
and the mechanism might be for that.
Immunity ? That doesn't even protect us so well from one year to
the next for the same strain.
And if the time was 11 years in the past then it might well
be 5 years now with air-travel.
-------------------------------------------

Hongkong had a H1-wave recently, which is going back now,
East China should be similar.
The next wave should be (>5?) months away
http://www.flutrackers.com/forum/showthread.php?t=140223&page=2
http://www.flutrackers.com/forum/showthread.php?t=150680

 

[Giuseppe]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

For the tropical flu season, we know there are two peaks: one during northern hemisphere winter and the second during spring/summer. Hardly flu disappears during the year in tropical zones.

H1pdm09 had some features that might be considered in the past as an intrasubtypic drift variants.

But a in depht genetical analysis demonstrated that it was not a fully human reassortant rathen than a human-swine-avian one.

Its ability to Exchange segments with other strains makes this virus unique and possibly a good parental strain for other future reassortants of animal origin.

The predominance of H1pdm09 in SE China this year may explain the skewed age-related H7N9 attack on the elderly people?

Has the innate heterotypic immune response been circumvented because of the antibody response toward old seasonal H1 strains in old people?

 

[gsgs]

Re: Discussion - Chinese researchers speculate that Influenza A(H7N9) could cause a severe pandemic

how would H1 explain the age pattern ?

And I'd liked an explanation that explains both,
the age and gender imbalance and why we don't see this with H5N1 !

new H1 segments also reassorted well in the H5 and H9
reassortment experiments