NYT on H2H; avian flu/pandemic definitions
NY Times: Human Flu Transfers May Exceed Reports. (BugMeNot NYT logins)
The numbers are still relatively small, and they do not mean that the virus has mutated to pass easily between people - a change that could touch off a worldwide epidemic. All the clusters of cases have been among relatives or in nurses who were in long, close contact with patients.
But the clusters - in Indonesia, Thailand, Turkey, Azerbaijan, Iraq and Vietnam - paint a grimmer picture of the virus's potential to pass from human to human than is normally described by public health officials, who usually say such cases are "rare."
Until recently, World Health Organization representatives have said there were only two or three such cases.
This is a kind of retrospective, "whoops, we low-balled this before" article. So oddly enough, it doesn't mean anything big is happening now, just that the World Health Organization wasn't being candid about things that have happened in the past. I think most people who were paying close attention to the Turkey cases back in January believed there were clusters of human-to-human transmission occurring.
The weird part is, the WHO has started saying, "Hey, we've had human-to-human transmission before, so it's not that big a deal," about the recent family cluster in Indonesia. But they shouldn't be surprised that people were taken off guard, because they've done their best to publicly downplay or dismiss any previous human-to-human transmission up until now. And they're doing the same thing regarding the pandemic alert levels now, in this same article - saying we can't be in phase 4 (see a chart of pandemic phases here), because phase 4 is a lot worse than we think. Here's the definition of phase 4:
Phase 4. Small cluster(s) with limited human-to-human transmission but spread is highly localized, suggesting that the virus is not well adapted to humans.
To me, that sounds like where we are now. The anonymous public health experts at Effect Measure said we were at phase 4 months ago. And yet the WHO says not:
Dr. David Nabarro, chief pandemic flu coordinator for the United Nations, said that even if some unexplained cases were human-to-human, it does not yet mean that the pandemic alert system, now at Level 3, "No or very limited human-human transmission," should be raised to Level 4, "Increased human-human transmission."
Level 4 means the virus has mutated until it moves between some people who have been only in brief contact, as a cold does. Right now, Dr. Nabarro said, any human transmission is "very inefficient."
Level 6, meaning a pandemic has begun, is defined as "efficient and sustained" human transmission.
Ms. Cheng of the W.H.O. said that even if there were more clusters, the alert would remain at Level 3 as long as the virus dies out by itself.
The only explanation for this I can see is that they think if a cluster dies out, that particular virus won't be passed on to anyone else, and so any progress made towards human adaptation in that virus would die out. I suppose that makes sense, but doesn't it say something that whatever virus is circulating in birds now is becoming human-to-human transmissible when humans do catch it?
It's fairly likely that sooner or later the WHO will be pressured by events to upgrade our alert level to phase 4. When they do, they'll be at pains to explain to us why this isn't a big deal... mostly so that businesses and financial markets don't overreact. But they'll have set it up for an overreaction, with all this noise about how 4 is a big change.
**
Reading the latest Sandman and Lanard column on H5N1, I realized I've made some of the communication errors they talk about, like using "bird flu" or "avian flu" when what I really mean is "pandemic flu". I guess I've picked up on the trend of using these terms interchangeably, and figured it would be obvious what I meant from context. But it's misleading, because even if and when we get H5N1 in North America in birds, it won't mean the pandemic is upon us. And if we never get H5N1 in North America in birds, it won't mean we're safe from a pandemic. So here are some "bird flu" definitions.
(HPAI) H5N1: (Highly Pathogenic Avian Influenza) H5N1. The H and the N numbers refer to structural components of the virus, and all influenza viruses, avian and human, can be classified by their H and N numbers. The 1918 pandemic was caused by H1N1, which became the seasonal flu virus for awhile after that. Although LPAI avian influenza viruses exist, when a news report says that H5N1 has been found (in birds or humans), they mean the highly pathogenic kind, unless they say otherwise.
Many news articles now use "bird flu" or "avian influenza" to refer exclusively to H5N1, but other Hs and Ns do exist. So if you see an old article talking about avian influenza in, say, Connecticut, that doesn't mean The Bird Flu has been here. It's either a different H and N, or LPAI.
And even if H5N1 fizzles out and goes away, that doesn't mean another subtype won't emerge from birds and become a human virus. So when experts say that a flu pandemic is virtually inevitable some time in the future, they mean some flu, of some subtype. And that is a virtual certainty, because the world does tend to have a couple flu pandemics every century.
H5N1 is currently an Avian influenza, or bird virus. This means it is primarily carried, transmitted, and contracted by birds. Comparatively few humans have gotten it, but it is still a virus of birds.
If and when H5N1 ever becomes fully adapted to humans, in effect a human virus, we'd face an influenza pandemic. (A "pandemic" is by definition in humans, according to Sandman and Lanard, although you may see faulty references to a "pandemic in birds". A "bird flu pandemic" is a misnomer too, the "bird" part left over to describe the origin of the virus.) A pandemic could start anywhere where humans were catching H5N1. Once there was a human-adapted H5N1 virus in China or Indonesia or Africa, it would be around the world in weeks... and whatever PETA says, going vegan wouldn't save us. So all the poultry industry's assurances that we're safe from a pandemic because our chicken farms don't have (or won't get) H5N1 are bullshit. They're based on a faulty assumption: either that the spread in birds is indistinguishable from a possible pandemic, or that the pandemic would need to come from birds in our own country.
On the positive side, even if a poultry farm in your country, state, or city did have an outbreak, you'd be very unlikely to catch H5N1 from that... because that H5N1 would still be a bird virus. There would be some risk to the poultry workers, but that could be minimized by culls and use of protective equipment. There would be a non-nonexistent risk of catching H5N1 from preparing and eating poultry, but that risk would be extremely small. So even if HPAI H5N1 showed up in chickens Connecticut, that wouldn't put us at higher risk of a pandemic. In theory it's possible that the feared shift from bird virus to human virus could happen anywhere, including the U.S., but most people think it's far more likely to occur in places where it spreads in poultry unchecked, where animal surveillance is weak, where people live in close quarters with poultry, and where human cases are slow to be recognized and isolated.
Some Flublogia terms I find helpful in distinguishing the types of outbreaks:
B2B: bird to bird transmission. This refers to H5N1 in wild or domestic birds.
B2H: bird to human transmission. This refers to humans catching it from birds, usually domesticated poultry. The WHO usually assumes any human case is B2H unless and until they can't figure out how that could have happened.
H2H: human to human transmission. This refers to clear or suspected cases of humans contracting H5N1 from other humans. In "multigenerational" human transmission, where person A gives it to person B and person B gives it to person C, as is suspected in the recent Indonesian cluster, you might see H2H2H etc.
I know they won't, but I think it'd be great if the mainstream media started using these abbreviations. You see an headline that talks about an "outbreak" in country X, and you have to read the article to be sure which kind of outbreak they're referring to. And these categories make nice little mental slots to put news items in, when you're trying to get an overall picture of what's going on.
For myself, I'm going to try to use bird flu/avian flu and pandemic flu more precisely in the future, so I don't contribute to any misunderstandings. If I slip up, let me know.
The numbers are still relatively small, and they do not mean that the virus has mutated to pass easily between people - a change that could touch off a worldwide epidemic. All the clusters of cases have been among relatives or in nurses who were in long, close contact with patients.
But the clusters - in Indonesia, Thailand, Turkey, Azerbaijan, Iraq and Vietnam - paint a grimmer picture of the virus's potential to pass from human to human than is normally described by public health officials, who usually say such cases are "rare."
Until recently, World Health Organization representatives have said there were only two or three such cases.
This is a kind of retrospective, "whoops, we low-balled this before" article. So oddly enough, it doesn't mean anything big is happening now, just that the World Health Organization wasn't being candid about things that have happened in the past. I think most people who were paying close attention to the Turkey cases back in January believed there were clusters of human-to-human transmission occurring.
The weird part is, the WHO has started saying, "Hey, we've had human-to-human transmission before, so it's not that big a deal," about the recent family cluster in Indonesia. But they shouldn't be surprised that people were taken off guard, because they've done their best to publicly downplay or dismiss any previous human-to-human transmission up until now. And they're doing the same thing regarding the pandemic alert levels now, in this same article - saying we can't be in phase 4 (see a chart of pandemic phases here), because phase 4 is a lot worse than we think. Here's the definition of phase 4:
Phase 4. Small cluster(s) with limited human-to-human transmission but spread is highly localized, suggesting that the virus is not well adapted to humans.
To me, that sounds like where we are now. The anonymous public health experts at Effect Measure said we were at phase 4 months ago. And yet the WHO says not:
Dr. David Nabarro, chief pandemic flu coordinator for the United Nations, said that even if some unexplained cases were human-to-human, it does not yet mean that the pandemic alert system, now at Level 3, "No or very limited human-human transmission," should be raised to Level 4, "Increased human-human transmission."
Level 4 means the virus has mutated until it moves between some people who have been only in brief contact, as a cold does. Right now, Dr. Nabarro said, any human transmission is "very inefficient."
Level 6, meaning a pandemic has begun, is defined as "efficient and sustained" human transmission.
Ms. Cheng of the W.H.O. said that even if there were more clusters, the alert would remain at Level 3 as long as the virus dies out by itself.
The only explanation for this I can see is that they think if a cluster dies out, that particular virus won't be passed on to anyone else, and so any progress made towards human adaptation in that virus would die out. I suppose that makes sense, but doesn't it say something that whatever virus is circulating in birds now is becoming human-to-human transmissible when humans do catch it?
It's fairly likely that sooner or later the WHO will be pressured by events to upgrade our alert level to phase 4. When they do, they'll be at pains to explain to us why this isn't a big deal... mostly so that businesses and financial markets don't overreact. But they'll have set it up for an overreaction, with all this noise about how 4 is a big change.
**
Reading the latest Sandman and Lanard column on H5N1, I realized I've made some of the communication errors they talk about, like using "bird flu" or "avian flu" when what I really mean is "pandemic flu". I guess I've picked up on the trend of using these terms interchangeably, and figured it would be obvious what I meant from context. But it's misleading, because even if and when we get H5N1 in North America in birds, it won't mean the pandemic is upon us. And if we never get H5N1 in North America in birds, it won't mean we're safe from a pandemic. So here are some "bird flu" definitions.
(HPAI) H5N1: (Highly Pathogenic Avian Influenza) H5N1. The H and the N numbers refer to structural components of the virus, and all influenza viruses, avian and human, can be classified by their H and N numbers. The 1918 pandemic was caused by H1N1, which became the seasonal flu virus for awhile after that. Although LPAI avian influenza viruses exist, when a news report says that H5N1 has been found (in birds or humans), they mean the highly pathogenic kind, unless they say otherwise.
Many news articles now use "bird flu" or "avian influenza" to refer exclusively to H5N1, but other Hs and Ns do exist. So if you see an old article talking about avian influenza in, say, Connecticut, that doesn't mean The Bird Flu has been here. It's either a different H and N, or LPAI.
And even if H5N1 fizzles out and goes away, that doesn't mean another subtype won't emerge from birds and become a human virus. So when experts say that a flu pandemic is virtually inevitable some time in the future, they mean some flu, of some subtype. And that is a virtual certainty, because the world does tend to have a couple flu pandemics every century.
H5N1 is currently an Avian influenza, or bird virus. This means it is primarily carried, transmitted, and contracted by birds. Comparatively few humans have gotten it, but it is still a virus of birds.
If and when H5N1 ever becomes fully adapted to humans, in effect a human virus, we'd face an influenza pandemic. (A "pandemic" is by definition in humans, according to Sandman and Lanard, although you may see faulty references to a "pandemic in birds". A "bird flu pandemic" is a misnomer too, the "bird" part left over to describe the origin of the virus.) A pandemic could start anywhere where humans were catching H5N1. Once there was a human-adapted H5N1 virus in China or Indonesia or Africa, it would be around the world in weeks... and whatever PETA says, going vegan wouldn't save us. So all the poultry industry's assurances that we're safe from a pandemic because our chicken farms don't have (or won't get) H5N1 are bullshit. They're based on a faulty assumption: either that the spread in birds is indistinguishable from a possible pandemic, or that the pandemic would need to come from birds in our own country.
On the positive side, even if a poultry farm in your country, state, or city did have an outbreak, you'd be very unlikely to catch H5N1 from that... because that H5N1 would still be a bird virus. There would be some risk to the poultry workers, but that could be minimized by culls and use of protective equipment. There would be a non-nonexistent risk of catching H5N1 from preparing and eating poultry, but that risk would be extremely small. So even if HPAI H5N1 showed up in chickens Connecticut, that wouldn't put us at higher risk of a pandemic. In theory it's possible that the feared shift from bird virus to human virus could happen anywhere, including the U.S., but most people think it's far more likely to occur in places where it spreads in poultry unchecked, where animal surveillance is weak, where people live in close quarters with poultry, and where human cases are slow to be recognized and isolated.
Some Flublogia terms I find helpful in distinguishing the types of outbreaks:
B2B: bird to bird transmission. This refers to H5N1 in wild or domestic birds.
B2H: bird to human transmission. This refers to humans catching it from birds, usually domesticated poultry. The WHO usually assumes any human case is B2H unless and until they can't figure out how that could have happened.
H2H: human to human transmission. This refers to clear or suspected cases of humans contracting H5N1 from other humans. In "multigenerational" human transmission, where person A gives it to person B and person B gives it to person C, as is suspected in the recent Indonesian cluster, you might see H2H2H etc.
I know they won't, but I think it'd be great if the mainstream media started using these abbreviations. You see an headline that talks about an "outbreak" in country X, and you have to read the article to be sure which kind of outbreak they're referring to. And these categories make nice little mental slots to put news items in, when you're trying to get an overall picture of what's going on.
For myself, I'm going to try to use bird flu/avian flu and pandemic flu more precisely in the future, so I don't contribute to any misunderstandings. If I slip up, let me know.