The New Scientist has a story this week asking whether flu vaccines really protects the elderly. It's not a new question. Careful epidemiological analyses of national mortality data has seemed to show no change in mortality amongst the elderly when vaccination for seasonal influenza ramped up starting in 1980. On the other hand, careful randomized clinical trials in specific populations seemed to show substantial protection.
The problem is more technically difficult than appears at first sight. On the one hand in a clinical trial you are making individual level measurements of both exposure (vaccination) and outcome (dying from influenza), while on the other, you have individual outcomes (mortality) but a group level of exposure (vaccination coverage). It would seem intuitively obvious that if vaccination coverage goes up then mortality should go down, but that depends on the assumption that mortality and vaccination are in the same people (the people that are dying might not be the ones who were vaccinated, for example).
In a randomized clinical trial you are comparing two populations whose differences are randomly distributed between them and whose main systematic difference is whether they were vaccinated or not. This allows the use of powerful statistical techniques to determine how likely any differences could have been due to chance alone. When comparing populations over time, however, you are comparing groups whose differences from year to year might vary substantially and are not randomly distributed. Two types of differences are important. Those related both to whether a person is vaccinated and whether they will contract the flu. For example, if seasonal flu vaccination by age changes from year to year and we know the risk of dying of influenza does as well, this could obscure the effects of vaccination over time. These kinds of differences are called confounders. Another kind of difference relates to those that affect how well the vaccine works, for example, the degree to which a seasonal vaccine is matched to the circulating strains in any one year or the virulence of the virus over time. These kind of yearly differences are called effect modifiers.
Where is this leading? It turns out that both between group confounding and between group effect modification can have drastic effects on the estimates of group level measures of association (this is the problem of bias in ecologic design). This could be biasing or obscuring the mortality trends over time (an ecologic comparison).
I'd like to say The New Scientist story sheds some light on the disparity between the two contradictory lines of evidence, but I found it incomprehensible.
A new analysis has revealed that elderly people are still dying of flu, but far fewer than 30 years ago - and those who are dying are older. This has not only muddied the waters in determining the effectiveness of vaccinations programmes, but it suggests we are due for another flu pandemic.
Last week, Kristin Nichol of the University of Minnesota in Minneapolis told the largest flu meeting ever, in Toronto, Canada, that when the Dutch boosted vaccination rates from less than 50 per cent of the elderly population to more than 80 per cent during the 1990s, deaths linked to flu fell by one fifth in all over-65s, and by half in those under 70.(New Scientist)
On the other hand, flu researcher Tom Reichert of Entropy Limited was reported to have said excess morality from flu has been declining since the 1968 pandemic, the decline masked by the large increase in the at risk population, but independent of vaccination programs. But New Scientist also reported him to say those over 80, now four times as numerous as 20 years ago, are still dying of flu, perhaps because they are less responsive to the vaccine. Huh? Lost in translation, perhaps.
In any event, the vaccination picture remains muddled. Another little flu mystery to add to the already long list.
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New Scientist has had its problems. . . .
"Where is this leading?"
Hopefully, to an end of blanket statements saying that influenza vaccines work.
If they can do a large double-blind study on ARDS over several years, then why can't they do the same for influenza vaccine?
If the vaccine doesn't work, we are spending a good deal of capital that could be spent elsewhere and if the 1950's vaccine production technology hasn't worked...maybe we can research and come up with a better technology and an effective vaccine.
Revere, any source on the start to finish for the Toronto meeting? Lots of appetizers from the meeting but no meat and potato's.
Randy: I have been told you will be able to purchase access to streaming video of the whole thing for $450 but don't know any more. There was a "no rejection" policy for papers and posters so there was a lot of junk there, I think. Much of it will probably only be published in vastly modified form or not at all.
This data on mortality is not new. What they did not mention though is the rate of secondary infections including post-influenza pneumonia and hospitalization are lower in the vaccinated elderly compared to the non-vaccinated who develop seasonal influenza.
A related issue is the CDC's vaccine ration plan for the pandemic that specifically excludes the elderly in nursing homes from priority access to vaccines. The rationale they provide for this statement is: "elderly in nursing homes and those who are immunocompromised and would not likely be protected by vaccination". If this is true, why the big push each year to vaccinate these folks? This statement in the CDC ration plan seems to contradict the data showing reduced secondary infections and rates of hospitalizations in the group after flu vaccination. Please help me understand this.
Thanks,
Grattan Woodson, MD
Gratt: No, it's not new. The disparity with Simonsen and Reichert's data and the trials has been going on for a while. This was the first time that Reichert has said there has been a general decline since the 60s independent of strain or vaccine, however, at least that I know about. It was also in New Scientist and got picked up so I thought it useful to discuss it (again). I've posted on it before. The question of vaccine policy hangs over this issue and it has become contentious for that reason.
The evidence is quite clear and consistent...existing technology for seasonal influenza vaccine doesn't work and has never worked very well at all...despite the spin and doublespeak...
...and if it doesn't work for seasonal influenza, you can forget it for pandemic influenza...not withstanding the fact that current production capability is a joke!!!!!!!!
The bottom line is there are better ways to spend limited resources.
Influenza vaccines in humans and birds don't prevent anything...all they do is provide the virus a place to hide and evolve.
Tom: The evidence is neither clear nor consistent. That is the nub of the problem. I'm talking about evidence, here, not your belief or conclusions. You need to be more careful in your statements which you give as "fact" but which are really interpretations of contradictory evidence.
Thanks Revere.
Point well taken.
In the future, I will try and remember to add the...in my opinion part...
As always...thanks for the opportunity.
it does work .. sometimes.
There are clear studies which prove it.
And since it's unlikely that in those cases where
it doesn't work it would counteract by increasing the
mortality ... it does also "work" in the global
general setting.
The question is, how large the effect is.
And I don't understand why they can't figure this out.
Despite revere's and new scientist's attempts to explain it.
Are the data from these researchers available,
so we can check ?
Why only look at Netherlands ? Look at all countries,
regions , their vaccination strategies and mortality data.
Revere, so in your opinion it always gives "some" protection even though its limited? Also and dont let me put words in your mouth if its not right, we might get back to work and in the saddle about 1 day sooner than if we hadnt taken it...correct?
Okay if this is so and its only a day then why take it? Its 30 bucks for starts is a reason not to take it and many dont so the coverage sucks. The bug always finds a way around it or it comes in as a novel new bug like H5N1. Granted it has pieces from the existing bugs out there and H5N1 if it comes will likely have pieces from those bugs too. This is where I disconnect with vaccine, Tamiflu and other antivirals. I REALLY liked the statins thing where its posited that it might reduce cytokine storm, but with no data to prove it yet. The body takes care of itself if you can stop that from happening as I understand it.
Have we goat roped ourselves with all of the vaccines that we have taken across the years? Have we created superbugs? All I know is that it made me sick as a dog in the military being forced to take it. I would have to report to work if the fever was less than 102 and it invariably would load my lungs up with funk that would take weeks to recover from. I never took it before the military, or after. Didnt get flu, nor did I get colds as a rule. Snifflies a bit but nothing has taken me down except for the flu shots. Get sick to not be sick? Mmmmmm?
Old people taking it? They are pretty much germ factories anyway so giving them flu shots does what specifically? Does it keep them alive to live in nursing homes, hospitals or to live what existence? Sure, I would like both of my parents to still be here but they arent and they never took the shots. Did not taking it make them healthier or not healthier? This is a question I cant sort out in this seesaw we keep riding about vaccines. Are the people in the homes and hospitals better off taking it or not? Sounds a little mean but why give it to someone who is in their say 80's? The effect is if its working will be to produce more living ...old people. Are we interrupting the natural balance to the point that nature is producing more and more nasty shit bugs, or upping the ante with old bugs? Do vaccines produce a short term response in a species that is always for the better part overcome at some later date?
Your read plz.
Randy: The science here is difficult and the data are contradictory. The clinical trials show it is effective. The long term mortality data do not show obvious effect. There are possible explanations but we don't know. I don't have an opinion. I will continue to get vaccinated pending further info.
"Then why does the vaccine appear to work in laboratory testing of efficacy where direct viral challenge is used?
In the case of in-laboratory experiments to test vaccine effectiveness, the vaccine is produced with a test virus that is maintained in cold storage frozen in timepreventing the normal genetic drift that occurs with time in natural field environments. Under these artificial conditions, the vaccine works every time
However, under field conditions, when there is a vaccine production lag period allowing the virus to genetically drift, effectiveness is compromised or is not there at all
It is a not unusual at all for treatments etc. that work in theory and under laboratory conditionsbut not to work when introduced to field applications.
There is some field evidence that seems to back up this hypothesis. In Barrys text, The Great Influenza, those that were infected in the first wave, were only partially protected in the second wave and completely unprotected in the third waveso the genetic drift even outwitted the best of all inoculationsnatural vaccination by field infectionwithin the relatively short time frame of a pandemic.
This is further reinforced by the fact that significant H1N1 epidemics continued until the late 1920salso indicating that the virus drifted away from natural immunity."
Revere.
You write that..."The clinical trials show it is effective."
Are the clinical trials you mention based on anecdotal information?
Are the findings of the clinical trials unanimous?
Could you provide links to the trials mentioned.
Thanks.
Sorry, I forgot to mention that the quote at the top of my last post is from a paper I wrote called...H5N1 Risk Assessment - Can We Read the Writing on the Wall?. It is avaliable on Pandemic Flu Information Forum Page 4.
the links are in the vaccine-thread of that same forum
Thanks gs. I will read the links.
Everyone would like influenza vaccine to work. Unfortunately, they have not done the required studies to prove that it works.
I do not believe a finding a casual relationship between vaccination and some level of protection very comforting when all of our pandemic preparedness is placed on one technology that doesn't work or at least doesn't work very well (Tamiflu) and a vaccine that not only is questionable in terms of level of protection but also will not be produced for approx. a year (in my opinion) after the pandemic starts...which makes it doubly useless...
...while there are technologies avaliable that do work.
1) pneumococcus vaccine 2) broad spectrum antibiotics for secondary infections 3) oral electrolyte powders that could be mixed at home 4) moderate short term prednisolone treatment to modulate the immune system and anti-fever medication like acetominophen.
The surge capacity for these therapies is not there and all supplies will be exhausted in the first month of a pandemic...as will existing medical care (SARS in Toronto is proof of that).
Lastly, you would think with billions on the line and the resources of the vaccine companies who will make the profit and the Government that does not want to admit they made a mistake by taking the easy road with their 'magic pills'...
...you would think that they would have provided a little more convincing data in the past ten years...that's all.
If they can do double blind studies in ARDS where people do die...then it seems they could do a double blind study for influenza vaccine, unless they were afraid what they might find out after the fact...
...and that is not to say that a new vaccine technology that can provide a novel type of vaccine in a month, may overcome the significant limitations of the present vaccine.
Looks like this issue isn't the least bit cloudy after all. The vaccine either works, or it doesn't. This has either been proved, or it hasn't, because the required studies either have or have not been done.
Influenza vaccines don't work against influenza, but the pneumovax does, and prednisone helps, too. I'm learning all kinds of stuff here.
and either you believe it or not...
I think the vaccine does work.
But probably not so well in the elderly.
Remember the recent study from the military
where all recruits are vaccinated ?
Was it here or in a forum ? I might search
a link
"and either you believe it or not..."
gs. I don't think science should be run on faith, that is for religion.
The fact that we are still asking ourselves this question says it all.
We have very limited resources for a very big problem that will arrive too soon for everyones liking.
I would like to see every child have treatment avaliable if not medical care. At the moment that is not possible given their concentration on Tamiflu and egg based vaccine from the 1940's.
They have an obligation to show us the studies that prove their 'faith' in this vaccine.
When you base your whole defense system on a chicken and egg based vaccine...in a pandemic where the virus has a natural predisposition to kill chickens and eggs...there is not a chance in hell that they will deliver.
And I think after the fact, that Tamiflu will be the biggest strategic mistake of the twenty-first century.
But we can't do anything about it...except comment!!