Monday, September 13, 2010

Conflicts of interest are not always financial. Role up your sleeves...and get your flu vaccine?

I joined this blog in December 2009.  There were several reasons for this including what I saw was a great need for conversation among hospital epidemiologists and infection preventionists around complex and important issues such as N95 masks in 2009 novel H1N1, ADI for MRSA and mandatory influenza vaccination of HCW.  That's why I was so excited to see that SHEA was finally releasing a position paper endorsing "a policy in which annual influenza vaccination is a condition of both initial and continued HCP employment and/or professional privileges."  I was so excited in fact, that I haven't read the document.  To be fair to myself, I've been pretty busy and I've seen several talks and debates on the issue. However, I was excited because it would awaken the debate again within the medical community and, more importantly, this blog.

Dan, Mike and I have all commented on the conflict of interest issue. It is true that several authors of the SHEA position paper have financial ties to vaccine manufacturers.  I agree, as I probably said 1000 times during high school debates, that 'perception is key' and that ideally we could produce documents such as this SHEA paper free of financial conflicts.  However, given that this document has been produced, what can and should we do with it?  How will we interpret it in the light of other organizations (e.g. AAP) coming to the same conclusion? Additionally, to be fair to the document and process, this isn't purely a SHEA position paper, but rather it was "approved by the Board of the Society of Healthcare Epidemiology of America and endorsed by the Infectious Diseases Society of America."

You could argue that we should post or even eliminate all of the potential "financial" conflicts of all of the board members of these societies and I would, at first pass, agree with you.  So now, in the future, we might have all board members and all guideline writers be free of all financial conflicts of interest. That may be theoretically possible for one subject, but all subjects? I doubt it.  I also don't think that "financial" conflicts of interest are the most important or result in the most bias.  I think it's not even close; but more on that in a minute.

Now if you think I've gone off my rocker (again), well, I was lead author on a SHEA guideline back in 2007 titled "Raising standards while watching the bottom line : Making a business case for infection control," and that guideline was conceived of, supported, edited, modified and approved by many members of the SHEA board.  In my opinion, a majority of those on the SHEA board must have pushed for this new flu vax position paper knowing what the outcome would be.  In fact, didn't SHEA produce a 2005 position paper containing a different recommendation? So why go through the effort to produce another document so soon, if they didn't know it would produce a different or this exact recommendation? Importantly, the SHEA position paper adheres to all current guidelines and lists financial conflicts of the authors. Nothing is perfect, but I don't think we should discount the recommendations for that reason.

On to another subject.  In April and June of this year I wrote posts discussing what I see is the most important bias in science and in life. That bias is confirmation bias.  My first post on the subject discussed how all of us that have pre-specified opinions, especially ones that are well known to others, root for results of new trials to support our pre-existing beliefs. It's just natural. This tendency for people to favor information that confirms preconceptions regardless of whether the information is true can influence our search for information, how we interpret information and even our memory.  Now, I'm not sure a definitive study has been done, but I suspect that if you have stated a strong public opinion for or against a certain "thing" it would take a lot of money to get you to change your mind and I haven't even mentioned status quo bias. Cognitive biases....if only the solution was so simple as listing or eliminating financial relationships!

While I'm on the subject of definitive studies, I will first state that I have great respect for the Cochrane reviewers and the SHEA position paper authors (and of course my co-bloggers).  However, no amount of genius can overcome the lack of studies/data/funding that exists for the evaluation of infection prevention interventions. So, again, even though I've not read the SHEA paper or the Cochrane reviews, I can definitively say that they are both wrong. Why? No one has completed the necessary cluster-randomized trial in 50-100 hospitals during different influenza seasons with different vaccine-virus matches in different countries with different acuity levels of the hospitalized patient populations etc, etc, etc.  No one will.

To me, the key issue around mandatory vaccine for HCW is not whether the vaccine works, as Mike discussed on Saturday. Rather, it is how much better HCW compliance would be under a mandate. I think most can agree that mandates greatly increase vaccine compliance, but if the data suggests that the vaccine doesn't work, then the question shouldn't be whether or not to mandate the vaccine. The question should really be whether we even offer it to HCW at all, or less seriously, even bother tracking compliance.  I think Mike's post or rather the Cochrane reviews have far more serious implications that stretch way beyond HCW mandates. To me though, there is enough data to support the efficacy and safety of influenza vaccine both in direct protection and also herd immunity. Thus, I think the key issue is compliance; but again, I haven't read it (yet).

So, what would I have done if asked to determine the benefits of mandatory influenza vaccine in HCW?  I might have completed a different type of research synthesis, altogether. I could have taken data like Mark Loeb's 2010 JAMA paper showing the benefits of herd immunity imparted on the unvaccinated by vaccinating children in small rural communities in Canada. Then, I'd have built a decision-analytic type model accounting for the non-linearity of influenza transmission in hospitals, adjusted for various levels of HCW vaccination compliance, completed numerous sensitivity analyses and then reported in which hospitals, in which countries and in which influenza seasons (H3 vs H1) we would expect influenza mandates to be most effective. Too bad that's not gonna happen.  Oh, and people wouldn't believe the model anyway.  It's just math for goodness sake and nobody trusts equations. No, most of us would much rather put our faith in conflicted human beings.  Go figure.

No links today; gotta spend time reading SHEA's new position paper


  1. I agree, Eli, that the committee that wrote the guideline was probably selected with a predestined outcome. We've seen that before. And I think it's an example of groupthink.

    What I find most fascinating about all of this is that looking at the same studies two groups of epidemiologists came to exactly opposite conclusions--one group (that is apparently disinterested in US hospital policy given none of them even live in the US) concludes there is no evidence to support vaccinating healthcare workers, and the other group thinks the same data are so compelling that those who refuse vaccination should be fired.

    One other note: I think the bad economy fostered SHEA's guideline. The nursing shortage, which was quite problematic, has been abated by nurses returning to the workforce when spouses have lost jobs and by others delaying retirement. So if this were the economy of 5 years ago, when hospitals were doing everything possible to recruit nurses, I bet SHEA would have never made this recommendation. Time changes everything--5 years ago, I thought mandatory vaccination was a good idea!

  2. I agree that groupthink or other cognitive biases can play a large role in many group endevours, such as guideline writing.

    However, independent of that, taking four cluster trials in LTCF and extrapolating to acute care hospitals higher acuity and risk (e.g. NICU, transplant patients, cancer patients) is not a good idea. None of those studies (I suspect) approached 100% compliance either. There are other issues that I already mentioned in that 10x as many studies will be needed to actually come to the conclusion that Cochrane did. Also, I think neither group incorporated Loeb's JAMA study, which is far more enlightening.

    Eitherway, the Cochrane data or any of the reviewed studies should not be used to argue against a mandate since they didn't study that specifically. What they say is that moderate levels of vaccination of HCW is ineffective in LTCF. These data could easily be used to argue that moderate levels are not enough and we need higher levels and a mandate.

    I still don't know what's the right thing to do as far as HCW mandates for influenza vaccine. I do, however, think that further discussions of the existing data won't really get me the answer. We need to model it and use other data like the Loeb paper to get us closer to the answer.

  3. I do want to point out two models referenced in the SHEA paper that support HCW vaccination. (yes it helps to read the paper!) These models were European and not biased by any US healthcare issues. From the SHEA PP: "Importantly, modeling studies have estimated that in both acute care and long‐term care settings, there is no HCP vaccination rate above which additional HCP vaccination coverage will not lead to further protection of patients.4,5 In these studies, vaccination of 100% of HCP in the acute care model resulted in a 43% reduction in the risk of influenza among hospitalized patients and a 60% risk reduction among nursing home patients."


    4.van den Dool C, Bonten MJ, Hak E, Wallinga J. Modeling the effects of influenza vaccination of healthcare workers in hospital departments. Vaccine 2009;27(44):6261–6267.

    5.van den Dool C, Bonten MJ, Hak E, Heijne JC, Wallinga J. The effects of influenza vaccination of healthcare workers in nursing homes: insights from a mathematical model. PLoS Med 2008;5(10):e200.
    First citation in article, CrossRef, PubMed