Swine flu now a "full-scale pandemic"

[MattusMaximus]

What makes it different is the rate it has spread, the danger doesn't lie in its current lethality, what is worrying is if it mutates into something that IS more lethal.

Imagine a flue that is highly lethal and spreads across the world in 22 weeks.

Ah, in my opinion this is a valid concern. Probably one which the CDC and WHO agree with, seeing as how influenza viruses are highly mutagenic.

Wash those hands, folks. Wash those hands...

 

[1337m4n]

That's why goverments are keeping a close eye on what's happening. It may turn out to be nothing, but there's a chance it could become a big problem and they want to be prepared. Of course the media always goes nuts with these things and make it sound like Aporkalypse* Now.

I suppose that's understandable. It's always good to be cautious, and I can't say I wouldn't do the same were I in a position of government.

But I just hate the fearmongering. The media made an equally huge deal out of "bird flu", which as far as I know turned out to be practically nothing. Forgive me for not being scared by this latest cry of wolf. What happens when one of these diseases DOES turn out to be dangeous, but nobody believes the media because they've heard the rhetoric a dozen times before? That was the whole moral of that old fable.




*That was a really terrible pun.

 

[drkitten]

And just to add another data point, folks, the typical influenza that we deal with regularly kills about 36,000 people on average every year in the U.S. alone. I'm not saying we should simply ignore H1N1, but we need to keep it in perspective.

Yes, let's.

The population of the USA is about 300,000,000 people.

If half in the USA caught H1N1 (which appears to be a not-unreasonable working assumption, given the way it's spreading), that would be 150,000,000 cases. If the 0.5% death rate holds constant, that would yield about 750,000 deaths.

More than twenty times as many people as are killed on average.

Reason for concern?

 

[a_unique_person]

Tens of thousands die from influenza every year (often with secondary pneumonia infections). What makes this strain so different from previous ones?

Just that there is no vaccine for it yet. There should be one available soon.

 

[shadron]

I still don't get the concern. Countless strains of the flu are very virulent. It's why we have "flu season" every year. It's an extraordinarily common virus in its many different strains. I'm not convinced swine flu spreads any more rapidly.

I've seen nothing in death rates to indicate that the swine flu is any more dangerous than lesser known flus.

I'm not particularly concerned about the lack of a vaccine. We are likely all exposed to numerous flu strains every year that weren't in the vaccine available in our area, if we even bothered to get the flu vaccine.

Comparisons to 1918 leave out how much more advanced available medical treatment is today, at least outside of the third world. We may not be able to "cure" the flu, but we can make it far less likely to kill you.

So, we'll mark you down as a H1N1 denier, eh?

With all due respect to you, I do think that WHO, even though political in a worldwide sense, does have the expertise in disease control to make that determination for a valid reason. Not only do they, but they seem to be backed up by almost all national public health organizations; indeed, many are disquieted by the WHO taking this long to react. If they're concerned, then I'm concerned.

Sure, we're more advanced than we were in 1918. Uh, maybe. Perhaps. Well, at least we know what a virus is; we even have some anti-viral drugs. That's a start, yes? No herd immunity; only occasional personal immunity; maybe even me, as I'm over 55 - are you? We now think we know why so many young people died in 1918, and we...uh, don't have a real clue about how to prevent cytokine storm^WPs from happening, do we? Some ideas...

 

[Damien Evans]

Yes, let's.

The population of the USA is about 300,000,000 people.

If half in the USA caught H1N1 (which appears to be a not-unreasonable working assumption, given the way it's spreading), that would be 150,000,000 cases. If the 0.5% death rate holds constant, that would yield about 750,000 deaths.

More than twenty times as many people as are killed on average.

Reason for concern?

That actually appears to be an incredibly unreasonable assumption. Here in Victoria we're in Flu Season, we've already moved to a modified sustain program and all the flu experts are predicting that 10-15% of Victorians will get infected.

Why would the percentage suddenly quintuple in the USA?

 

[Policenaut]

That sounds low considering the demographics in your area. Also the problem with this particular flu is that if it spreads aggressively you will likely catch it because you have no immunity to it unlike a regular flu. It could potentially be devastating for third world countries especially places where the average person has a poor diet and weak immune system to begin with. And the current normal seasonal flu is highly resistant to Tamiflu so just a bit of mingling could make the swine flu resistant too. This would mean that the only drug known to treat it would be Relenza. The vaccine could make this all null but it has to go through lots of testing. I don't think it will be available for several months at earliest.

 

[Skeptic Ginger]

Read up the definition of pandemic used by the WHO. It does not rely on lethality but on spread.

They should have raised this to level 6 over a month ago but did not want to cause panic.

Or seem like they were crying wolf.

 

[Skeptic Ginger]

I've survived the Anthrax Scare of '01, the SARS Plague of '03, and now I'm probably going to survive the Piggy Pandemic of '09.

Perhaps not something to joke about until we know what will happen when a large percentage of people fall ill.

This WHO update has a good summary of what's been seen so far.

Worldwide, the number of deaths is small. Each and every one of these deaths is tragic, and we have to brace ourselves to see more. However, we do not expect to see a sudden and dramatic jump in the number of severe or fatal infections.

We know that the novel H1N1 virus preferentially infects younger people. In nearly all areas with large and sustained outbreaks, the majority of cases have occurred in people under the age of 25 years.

In some of these countries, around 2% of cases have developed severe illness, often with very rapid progression to life-threatening pneumonia.

Most cases of severe and fatal infections have been in adults between the ages of 30 and 50 years.

This pattern is significantly different from that seen during epidemics of seasonal influenza, when most deaths occur in frail elderly people.

Many, though not all, severe cases have occurred in people with underlying chronic conditions. Based on limited, preliminary data, conditions most frequently seen include respiratory diseases, notably asthma, cardiovascular disease, diabetes, autoimmune disorders, and obesity.

At the same time, it is important to note that around one third to half of the severe and fatal infections are occurring in previously healthy young and middle-aged people.

Without question, pregnant women are at increased risk of complications. This heightened risk takes on added importance for a virus, like this one, that preferentially infects younger age groups.

Finally, and perhaps of greatest concern, we do not know how this virus will behave under conditions typically found in the developing world. To date, the vast majority of cases have been detected and investigated in comparatively well-off countries.

 

[Skeptic Ginger]

95, exactly, many unexpectedly young, but as Pax pointed out it's not how many but how wide. 48 countries, according to the CDC (57 reported elsewhere, CDC site seems to be a little behind): http://www.cdc.gov/h1n1flu/update.htm , and every state, including DC and Puerto Rico: http://www.who.int/csr/don/2009_05_27a/en/index.html ; in other words, it's in a location near you. Not too shabby for an infection detected 22 weeks ago in Mexico City, during an off-season. Those who shrug may want to reconsider. It's not the Black Death, but it's not a head cold, either.

Your WHO source for the 95 deaths is from May 27th. The WHO's number from today is 145 deaths.

It's very early in the flu season for the Southern hemisphere and in the North we may have seen a dampened number of cases because flu season is over. IE the weather conditions in which the virus spreads more easily is winter. Clearly the season is not over since the virus is still widely circulating.

In addition, and I'm not going to go around and around about this again, take it or leave it: the official confirmed case fatalities are not the same as the actual case fatalities.

With a disease like influenza that infects so many people and a world wide pandemic which includes a vast number of people with no medical care, no labs monitoring cases, people dying at home and so on, there is no way all the deaths are going to be confirmed and then reported to the WHO. Africa isn't doing much monitoring at all so that whole continent is not being counted.

 

[Skeptic Ginger]

And despite the reporting (and some ChickenLittles), having more to do with insufficient medical treatment or other conditions and not the inherent lethality of the disease itself.

This comment is full of inaccuracies. You are essentially telling us your uneducated opinion. For the actual facts see the info in the last WHO summary I posted in #49 above.

 

[Skeptic Ginger]

Tens of thousands die from influenza every year (often with secondary pneumonia infections). What makes this strain so different from previous ones?

The age group suffering the most severe disease is not the usual age group you see those worse cases in. And for the Northern hemisphere, it resulted in an out of season case rise.

Anything else is yet to be seen.

 

[Skeptic Ginger]

I'm not sure I understand all the hand wringing over this. Approximately 36,000 people die from the flu every year just in the US. No one seems overly concerned about that. ...

Except those of us who work in the infectious disease field.

 

[Skeptic Ginger]

...


*Understanding may be flawed

At least you are paying attention to the facts and not just looking for facts that merely support a preexisting misunderstanding.

 

[Skeptic Ginger]

Is it spreading at an exceptionally high rate?

Yes. But we also haven't watched the pot boil quite as closely. So it could be a matter of better observation. It was interesting to see some of the May flu cultures coming back as seasonal strains. 2009H1N1 shouldn't make the other strains more common. That leaves the possible explanation that we often quit culturing for flu before the season is really over.

 

[Skeptic Ginger]

I still don't get the concern. Countless strains of the flu are very virulent. It's why we have "flu season" every year. It's an extraordinarily common virus in its many different strains. I'm not convinced swine flu spreads any more rapidly.

I've seen nothing in death rates to indicate that the swine flu is any more dangerous than lesser known flus.

The age demographics in severe cases are a concern.

I'm not particularly concerned about the lack of a vaccine. We are likely all exposed to numerous flu strains every year that weren't in the vaccine available in our area, if we even bothered to get the flu vaccine.

End of season vaccine evaluation will typically show the vaccine covered 80-90% of the strains that actually circulated. Once in a great while like 2 years ago the vaccine was only a partial match due to genetic drift after the vaccine strains were chosen.

We use the law of diminishing returns when choosing the number of strains to include in the vaccine. If you wanted to cover every circulating strain you'd need many more than 3 strains in each year's vaccine. But for the strains you add after 3, you only get a minimal additional benefit. So 3 is the magic number.

The WHO samples circulating flu virus from sentinel sites year round. They update the vaccine recommendation every 6 months. So it's a pretty good system most of the time.

Comparisons to 1918 leave out how much more advanced available medical treatment is today, at least outside of the third world. We may not be able to "cure" the flu, but we can make it far less likely to kill you.

That's a common myth. While we can manage secondary pneumonia better now, and we have some anti-viral meds, that's no guarantee we couldn't see a very deadly flu pandemic regardless. The flu virus develops drug resistance fairly quickly, and with something like the HPAI H5N1 (aka bird flu) antibiotics are of little use since most fatalities are from the virus, not from secondary pneumonia.

Then there's that little problem of MRSA/flu coinfection we have seen with increasing frequency over the last 3 years. It causes a kind of flesh eating lung infection and it can kill despite treatment.

 

[Skeptic Ginger]

...

However, if all this attention to H1N1 gets more people to take their personal hygiene more seriously (washing hands, coughing into their sleeve, etc), then I think overall the attention is a good thing.

I've been using it as an excuse to quit the bad habit of shaking hands when meeting new people.

 

[Skeptic Ginger]

I suppose that's understandable. It's always good to be cautious, and I can't say I wouldn't do the same were I in a position of government.

But I just hate the fearmongering. The media made an equally huge deal out of "bird flu", which as far as I know turned out to be practically nothing. Forgive me for not being scared by this latest cry of wolf. What happens when one of these diseases DOES turn out to be dangeous, but nobody believes the media because they've heard the rhetoric a dozen times before? That was the whole moral of that old fable.....

The first problem you have here, as I see it, is getting your information from the news media in the first place. And the second problem is how you are assessing risk.

The news media wrote this virus off after there weren't bodies in the street in the first week. That was as unrealistic expectation for what one would see with a bad flu pandemic. True to form, once we had a few thousand infected we started seeing the fatalities. 1 death/4,000 cases is about average for flu. But take that same number and infect half the population and the death count really rises.

Now take away 90% of 36,000 annual flu deaths that occur in people over 65. This virus is not hitting the elderly much at all. If we see less than 3,600 deaths in the US from the 2009H1N1 by the end of next flu season, we will have dodged the bullet. Until next March, you cannot count your chickens as they haven't hatched.

Southern hemisphere countries will know in the next few months.



As for the HPAIH5N1, it continues to simmer. Again, just because the pandemic did not occur in 1997 when we had the first known fatalities (17 out of 33 cases) in Hong Kong is no reason to think we are out of the woods here. The current count as of June 2 is 433 confirmed cases and 262 fatalities. Since then Egypt has had 2 more cases.

But, the pattern has changed in the last dozen cases in Egypt. All the cases were in very young children. That suggests there are undetected cases in other age groups as it is unlikely the age pattern in actual cases is what has changed. That is not good since undetected cases can also mean person to person spreading may be occurring.

There is also another outbreak in wild birds in the Qinghai Lake region of China. Several years ago a similar outbreak was the precursor to increased spread of the virus.

Again, we don't know what any of this means. But the idea a deadly pandemic must occur as soon as we detect a new threat or else it isn't going to happen is foolish. No one knows how long the 1918 flu virus simmered before taking off. The current H1N1 has been smoldering in the pig populations for a while. HIV was detected in stored blood that was drawn decades before the epidemic started.

The news media doesn't understand this concept. But that doesn't mean there is no story here left to develop.

 

[MattusMaximus]

Yes, let's.

The population of the USA is about 300,000,000 people.

If half in the USA caught H1N1 (which appears to be a not-unreasonable working assumption, given the way it's spreading), that would be 150,000,000 cases. If the 0.5% death rate holds constant, that would yield about 750,000 deaths.

More than twenty times as many people as are killed on average.

Reason for concern?

Well, of course, if you make those assumptions then you've got a great argument. But, as someone else has noted, what is your evidence that 50% of the U.S. population would contract H1N1?

Wash those hands...

 

[drkitten]

Well, of course, if you make those assumptions then you've got a great argument. But, as someone else has noted, what is your evidence that 50% of the U.S. population would contract H1N1?

All right, I'll use the LOW end of the figures Damien Evans suggested -- 10% of the population, instead of 50%, catches the flu.

That means that instead of seeing 20x the normal number of deaths, we see 4x the normal number of deaths.

That's still a serious change from the norm.

Wash those hands...

Yes, that's definitely a good start. I hope you're not foolish enough to think it ends there.