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PostPosted: Thu Sep 24, 2009 12:02 am 
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OK I have a few issues here, does anyone know if they have altered their kit since the evaluation? Because according to THIS its only about
69% specific?
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5830a2.htm
I know this is the kit most places seem to be using.

Then I saw this today:
Quidel's test kit can detect swine flu

"How well it performs in detecting H1N1, however, has not been established. "
http://www3.signonsandiego.com/stories/ ... t-17266937


Seems like it was pretty well established on that MMRW report!

How many doctors are basing whether or not to give anti-virals on the results of this kit?

And WHY was no funding offered to companies that developed more accurate/specific kits for novel H1N1 this spring?

:doh: :(


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PostPosted: Thu Sep 24, 2009 6:27 am 
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Hello Happy...
Having been following your thoughtful commentary and one-liner-questions, it would seem that "connecting the dots" leaves little else; but, to view the "incompetent" CDC as being irresponsibly incapable of fulfilling that portion of their mission, which deals with "early warning recognition and tracking"... wittingly or not, sort of like submarine commanders rising to the surface and colliding with a surface vessel... why are these "incompetents" not relieved of duty, immediately?

Do they have "politically correct" tenure... are they, perhaps... at the very highest of levels of decision... "too-big-to-fail-like-banks" ??? Perhaps, 'tis their analysts and/or their briefers... have they all "lost their whistles"? I find it hard to believe that there are no loud voices screaming...

Take your most recent exemplar, for example (only one, among many):
"And WHY was no funding offered to companies that developed more accurate/specific kits for novel H1N1 this spring?"

"A large rose-tree stood near the entrance of the garden: the roses growing on it were white, but there were three gardeners at it, busily painting them red. Alice thought this a very curious thing, and she went nearer to watch them, and just as she came up to them she heard one of them say,

`Look out now, Five! Don't go splashing paint over me like that!'

`I couldn't help it,' said Five, in a sulky tone; `Seven jogged my elbow.'

On which Seven looked up and said, `That's right, Five! Always lay the blame on others!'

`YOU'D better not talk!'said Five. `I heard the Queen say only yesterday you deserved to be beheaded!' `What for?' said the one who had spoken first.

`That's none of YOUR business, Two!' said Seven.

`Yes, it IS his business!' said Five, `and I'll tell him--it was for bringing the cook tulip-roots instead of onions.'

Seven flung down his brush, and had just begun `Well, of all the unjust things--' when his eye chanced to fall upon Alice, as she stood watching them, and he checked himself suddenly: the others looked round also, and all of them bowed low.

`Would you tell me,' said Alice, a little timidly, `why you are painting those roses?'

`Leave off that!' screamed the Queen. `You make me giddy.' And then, turning to the rose-tree, she went on, `What HAVE you been doing here?'

`May it please your Majesty,' said Two, in a very humble tone, going down on one knee as he spoke, `we were trying--'

"`I see!' said the Queen, who had meanwhile been examining the roses. `Off with their heads!' and the procession moved on, three of the soldiers remaining behind to execute the unfortunate gardeners, who ran to Alice for protection..."
:think:


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PostPosted: Thu Sep 24, 2009 12:46 pm 
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Ironically,
this came out today:)
http://www.cdc.gov/mmwr/preview/mmwrhtm ... mm5837a1_e

Enjoy


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PostPosted: Thu Sep 24, 2009 1:15 pm 
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Quote:
OK I have a few issues here, does anyone know if they have altered their kit since the evaluation? Because according to THIS its only about
69% specific?
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5830a2.htm
I know this is the kit most places seem to be using.

Then I saw this today:
Quidel's test kit can detect swine flu

"How well it performs in detecting H1N1, however, has not been established. "
http://www3.signonsandiego.com/stories/ ... t-17266937


Seems like it was pretty well established on that MMRW report!


The problem here is that you're talking about two different things. You've got to distinguish a test's SENSITIVITY from its SPECIFICITY. They're not the same.

SENSITIVITY tells you the proportion of true positives (those who really have a disease) the test is able to detect.
SPECIFICITY tells you the proportion of true negatives (those who don't have the disease) the test correctly identifies.

So, applying this to what you wrote above, a test that has a 69% SPECIFICITY would correctly identify people WITHOUT the flu 69% of the time; that is, the test gives a negative result -- the result you'd expect for someone without the illness you're testing for -- 69% of the time. On the other hand, a flu test with 69% SENSITIVITY would correctly identify people who are actually sick with the flu 69% of the time.

The MMWR you linked to doesn't examine any rapid diagnostic test's specificity. (It only gives specificity data for the CDC's own lab PCR assay, the test against which the rapid tests are being compared.) The MMWR is exclusively about examining each RIDT's SENSITIVITY, their ability to turn out true positives in cases where someone has the flu, not true negatives in cases where they don't (specificity). The MMWR you cited is claiming the Quidel test was 69% SENSITIVE, not 69% specific.

Interestingly enough, tomorrow's MMWR has a little different view of Quidel's test sensitivity. Here's what it has to say:
Quote:
Rapid tests differ in their sensitivity and specificity for detecting seasonal influenza in respiratory specimens but generally have low to moderate sensitivity compared with viral culture or rRT-PCR. Previous RIDT studies have described the performance of the QuickVue Influenza A+B test (Quidel Corporation, San Diego, California) for detecting seasonal influenza in three different populations during 2008. Sensitivity when compared with rRT-PCR was low for all populations (median: 27%; range: 19%--32%)

They go on to say that the specificity of the RIDTs is much higher, usually in the 83-86% range and gave specificity for the Quidel from one study to be 99%.

This paints the picture of a lab test that is pretty good at ruling IN a disease when it comes back positive but isn't a very good predictor of whether someone has the disease when it comes back negative. They finally get around to saying what I've repeated over and over...treat the PATIENT, not the lab test. If someone has all the clinical signs and symptoms of the flu, you should treat them as if they have the flu, even if the test comes back negative, because the test isn't all that great.

Here's how the CDC put it:
Quote:
In this group of patients, although positive RIDT results performed well in predicting confirmed infection with pandemic H1N1 virus (positive predictive value: 92%), negative tests did not accurately predict the absence of infection (negative predictive value: 32%). These results affirm recent CDC recommendations against using negative RIDT results for management of patients with possible 2009 pandemic influenza A (H1N1) infection

http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5837a1.htm?s_cid=mm5837a1_x


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PostPosted: Thu Sep 24, 2009 1:30 pm 
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Hi:)

I do not think the CDC is incompetent.
I think they know exactly what is going on and have known since early this year.
I think they are doing something called "cluster management"
Some of it is a good plan. I do not agree with the method details.
I do not believe schools should be on the front line when all we needed was a bit of time until the vaccination campaign.

I think more should have been done to reduce the spread at schools.
I think children should be out AT LEAST 7 days not 24 hours based on the CDC's own research showing viral shedding at 8 days.
I believe doctors should be informed the rapid kits are not very good.

I believe they should have let the river out a bit more as there will be a lot of back pressure if people are caught off guard and that dam comes down.

The majority of people seem to all be convinced this is "normal flu" because that is exactly what they were told.
What happens when they find out that is not the case?

But do not be fooled, the CDC knows EXACTLY what they are doing.
IT appears to me, they want as many areas sick as possible BEFORE the real wave (hence the returning children to school after 24 hours) so that
they can get those people cared for and out of the way before the real wave comes.
Scientifically it does make sense.
And without a vaccine this makes total sense.

HOWEVER, since we have a vaccine, since we are in a neck and neck race with the flu for the vaccine, I feel they should have done more in the way of prevention of spread to SLOW it down. We know it can’t be stopped but you CAN slow it down. And that is ALL that was needed, TIME.

So I do not agree with how the schools are operating now, many with 30% + absenteeism and still open.
The children shouldn’t be the sacrificial lambs in this, when all we needed was about 8 weeks to push it off.

I hope I am wrong. I hope it is like they say and just normal flu.
I’m just not buying it. Especially with articles like this:
http://seattletimes.nwsource.com/html/h ... flu23.html

The CDC does NOT want to hurt people They are doing what model wise has proven the most effective way to manage a mass pandemic.
My fear is they didn’t let enough of the river water OUT, people will be caught off guard, and there has been too much back pressure built up at this time.

I worry, what happens when the dam comes down.

They are not stupid, but they are also not perfect. They took a guess on how best to manage this. Lets face it this is probably the first they have ever dealt with this. They have no pandemic experience, there will be things learned now that will protect people in future pandemics because they will have learned from their mistakes.

Right now, people need to know, this is coming, stock up some supplies,
make sure the parents are aware that it could very well help the children to have Hib and Ped-vax, get the seasonal flu vaccination when it comes out.

Too many people walking around right now, not having ANY idea what is about to come this fall. All they know is "this is just like normal flu"
Just like what Neapoltin told them in May.

That was an error.
It would have been better to say "we just do not know what it will do either way" and be honest then to give false security.

It is very important people maintain trust in them, it is better to say “I don’t know” then don’t worry its like normal flu. I realize this is new for them, and they are doing all they can. They need to think beyond the now though.
Any way you wrap this barring a miracle the river is coming.
Better swollen than a massive angry wave all at one time.

I do NOT think they are mocking us, or trying to harm us, I think they are all trying to figure out how to get us through this the best way they know how.
And so far they have done a wonderful job at putting up the dam. But you MUST let the water through, because if that dam goes down then what?


Know what I mean?
This could go badly.
Being in their shoes right now is not a good place to be.
I get upset you know, that things can be done better. I am very protective over children I want to see more prevention that way.
But overall I do empathize for what they are going through right now.


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PostPosted: Thu Sep 24, 2009 1:34 pm 
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OK and should correct TYPO:

make sure the parents are aware that it could very well help the children to have Hib and Ped-vax, get the seasonal flu (TYPO)vaccination when it comes out.

SEASONAL NOW and then NOVEL H1N1 vaccination when it comes out if they have weighed pro-con and ARE informed on what is really going on here.


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PostPosted: Thu Sep 24, 2009 2:33 pm 
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Happy, was your posting responding to me? How did we get from Quidel test sensitivity/specificity to whether the CDC is/isn't incompetent or does/doesn't know what they are doing? None of that was even mentioned in my posting, and I don't follow your jump to the topic.

Personally, I disagree with how the CDC is handling things. I advocated for school calendar changes all summer that would have placed the start of the academic year after the vaccine became available, and I thoroughly disagree with the way school closures are being handled. From past pandemics (and I've lived through 2 and worked through 1), it is abundantly clear that leaving schools open can PRECIPITATE a community epidemic wave and result in MORE community cases and a SHARPER -- not duller/more dispersed -- wave peak. Leaving schools open does NOT delay a major community pandemic wave long enough to allow pediatric cases to be handled first before the "real wave" hits, as you allege might be the CDC rationale. Instead, it brings on the "real wave" and ensures that, in addition to the pediatric cases from the schools, you'll have community cases piling into the ERs to be cared for sooner rather than later. Scientifically and epidemiologically, their actions do NOT make a lot of sense, even in a scenario where a vaccine might not ever be forthcoming but ESPECIALLY in light of the fact that a vaccine is less than a month away.

If you look historically at how past pandemics were handled, CDC seems to be just repeating the same old things done before, regardless of how effective those things turned out to be. It shows in their actions and in their communication style. So far, they've fallen into just about all the communication pitfalls discussed in the last 3 pandemics. They've also lost focus on what THEIR mission is...they are the Centers for Disease Control. They can and should be doing better.


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PostPosted: Thu Sep 24, 2009 3:33 pm 
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MKey1
No that was not a response to you, you are 100% correct in your statements.

I was writing fast this morning I am trying to do too much this morning between "real work" and posting information. I was listening to what Capeman was saying about the diagnostic as he is more familiar with it than I am and I need to slow down.
SENSITIVITY are SPECIFICITY are clearly the two different issues.

Although, as folks that have developed Rapid Diagnostics for years I can tell you both Capeman and I feel it is "not a very good test"
in that if we were not in a pandemic situation we doubt there would have been approval especially if the results were the deciding factor to prescribe an antiviral or not.

Do you know what I mean? That was the main point I was trying to drive across this morning.
Capeman thinks they are worthless and should not be used at all.
I think they could give some people 'peace of mind' or at least SOME information however, I would not balance the decision of a treatment on it.

Some people will say it is better than nothing, but others will say sometimes no information is better than incorrect information.

Do you concur?

I have to get back to work ive been on NCBI all morning and having a lot of computer issues today.


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PostPosted: Thu Sep 24, 2009 4:12 pm 
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MKEY
YOu said:
"I advocated for school calendar changes all summer that would have placed the start of the academic year after the vaccine became available, and I thoroughly disagree with the way school closures are being handled. From past pandemics (and I've lived through 2 and worked through 1), it is abundantly clear that leaving schools open can PRECIPITATE a community epidemic wave and result in MORE community cases and a SHARPER -- not duller/more dispersed -- wave peak. Leaving schools open does NOT delay a major community pandemic wave long enough to allow pediatric cases to be handled first before the "real wave" hits, as you allege might be the CDC rationale."


I say:
So we both DO agree that the schools should have been left closed until the vaccination campaign.

As far as my "allegation"
that is based on statements from THE WHO. I realize quite well it would not STOP the pandemic, but as I stated it could SLOW it down and buy time. As in the number of cases you are dealing with up front.

http://www.who.int/csr/disease/swineflu ... index.html


"The main health benefit of proactive school closure comes from slowing down the spread of an outbreak within a given area and thus flattening the peak of infections. This benefit becomes especially important when the number of people requiring medical care at the peak of the pandemic threatens to saturate or overwhelm health care capacity. By slowing the speed of spread, school closure can also buy some time as countries intensify preparedness measures or build up supplies of vaccines, antiviral drugs, and other interventions."


I personally believe in regard to concerns of
"Economic and social costs" which the WHO also notes,

that those should SHADOW in comparison to protecting the children in this country and all others. And yet it seems it was made a priority.

I believe there is no argument here, it seems that you and I both agree that not enough is being done to protect the children.


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PostPosted: Thu Sep 24, 2009 5:28 pm 
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Rapid flu tests miss many swine flu cases - US CDC

CHICAGO, Sept 24 (Reuters) - A study of rapid influenza tests found they miss many cases of swine flu and U.S. health experts said on Thursday they are not worth the trouble for this flu season.

A study looking at the effectiveness of a rapid flu test in the first few weeks of the H1N1 pandemic in May found it detected less than half of the cases later confirmed by more sophisticated tests.

MHealth and Human Services Secretary Kathleen Sebelius told reporters at a briefing that doctors should simply treat symptoms and not bother with testing.

'The flu is the flu is the flu,' she said.

The latest study, conducted by Dr. James Sabetta and colleagues at the Greenwich Hospital and the Greenwich Department of Health in Connecticut, shows why.
They found the rapid flu test detected just 47 percent of the pandemic flu cases later confirmed by a slower, but highly accurate test called real-time reverse transcription-polymerase chain reaction, or rRT-PCR, which checks for the genetic material of the virus.

The findings confirm an earlier study by the CDC that found quick flu tests caught just 40 to 69 percent of swine flu cases. That study, released in August, looked at three popular flu tests -- BinaxNow, made by Inverness Medical Innovations , Becton Dickinson's Directigen EZ Flu A+B test and Quidel's QuickVue.

http://www.forbes.com/feeds/afx/2009/09 ... 27655.html
*************
My question: If, as Kathleen Sibelius states, doctors should just treat symptoms and not test, WHY are doctors still using the rapid tests, falsely assuring families that their child does NOT have the swine flu? I've had several students say that they've had the fast test, it was negative, and they're back with their sniffles, sore throats, etc.


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