Root causes underlying the emergence of influenza vaccine mandates

Those that follow me on twitter or the blog have probably noticed my recent focus on trying to understand the emergence of compulsory influenza vaccination of healthcare workers. Before moving on from this topic, I wanted to share what I've learned in the process.

(1) There doesn't appear to be any estimate of the burden of nosocomial influenza in the US. We know healthcare-associated influenza does occur, but we don't have estimates for the proportion of influenza cases that occur in hospitals. Even if we did know the incidence, we don't have reliable estimates for what proportion is acquired from healthcare workers vs. visitors or family members. It seems like we'd need those numbers before pushing for a mandate.

(2) There is no data supporting the benefits of healthcare worker vaccination in acute care hospital settings. If we look at the CDC systematic review everyone quotes, there were only 4 randomized trials and all 4 were from long-term care settings. If we generously include the observational studies, 3 were from long-term care and only one was from a hospital setting. We are basing acute-care hospital policy on one observational study.

(3) Again from the CDC systematic review, "HCP vaccination rates ranged from 48% to 70% in the intervention arms and 5% to 32% in the control arms." Thus, there is no evidence that raising vaccination above 48% or 70% is beneficial in long-term care settings. Thus, if we have vaccination rates near 50%, do we need a mandate?

The last two things I learned are that none of the above matters. Science is not what is driving the push for mandates, unless you consider the studies showing mandates raise influenza vaccination rates among healthcare workers. Probably didn't need a study to show that.

(4) Yesterday, I wrote a post trying to bias the respondents of a twitter survey in favor of being cared for by a masked unvaccinated healthcare worker over a vaccinated one. As you can see by the results (below), despite my efforts, the large majority want their healthcare worker to be vaccinated. This is critical - despite the science, we just want people to be vaccinated. A huge driver behind influenza vaccine mandates must be this desire. Additionally, it's likely that masks are viewed negatively by patients. Vaccine mandates make folks feel safe and masks don't - very patient centered.

(5) The finally bit that occurred to me is that the reason vaccine mandates exist is because CMS and other governing bodies require hospitals to collect and report influenza vaccine coverage among their workers. There is also a target of 90% coverage that must be met. Thus, we have a QI target that exists despite minimal scientific evidence that it protects patients but we have to meet the target. And the only way to meet such an arbitrary target is through mandates. QED


  1. In reading this, I'm trying to reconcile your approach to influenza vaccination with your group's approach to "bare below the elbows." Both have some supporting evidence, but certainly not overwhelming evidence, for the overall policy. Should we presume your position is because one is a mandate, while the other is not?

    I also get the sense that point #4 is a bit of a straw man argument. Is it a vaccine mandate that makes people feel safe, or is it vaccination itself that makes people feel safe? Your argument makes it sound as though there is zero science behind vaccination, whereas your point is that there is little science behind a mandate policy, which is different. "Despite the science, we just want people to be vaccinated." Isn't it because of the science, we want people vaccinated?

    As for point #5, all I can say is that it is most definitely not the reason our institution has mandated vaccination. Targeting a QI measure was never part of the conversation.

    1. Interesting to connect BBE and mandatory vaccines. True there is lots of science around vaccinating individuals, but there seems to be little evidence that vaccinating HCW translates into direct benefits to patients outside of long-term care and there the benefits are ILI and not influenza. However, the difference between BBE and mandatory vaccines is that BBE is removing the white coat (we are doing this voluntarily and that's what Mike and others recommend) compared to mandatory injections +/- mask for unvaccinated. Seems like that should have a higher level of evidence with our without mandates.

      #4 I think the vaccine makes people feel safe and thus comfortable with the mandate so that they can always feel safe, if that makes sense.

      As for #5, I got there by reviewing the literature again. Since I think it is equally likely that mandates increase influenza transmission in hospitals. Why? I'm concerned that a vaccine with 50% efficacy could increase presenteeism since vaccinated folks will think their fever isn't influenza, when it could be, and then they'd go to work, when they shouldn't. Thus, for many institutions it is about getting compliance above 90%, which is the strongest argument in favor of mandates in the recent WSJ editorial

      Finally, I realize my opinions are hugely unpopular among infection control folks. My main concern (as I stated in my first post on the topic last week) is that if we don't honestly present the data to HCW when we implement the mandate (toolkit etc), we will be hurting ourselves in the long run and we won't fund the necessary studies to answer the important unanswered questions - where there are clearly many.

  2. As I have said many times before, we have SHEA to thank for this mess. I believe SHEA was the first to call for mandatory vaccination of healthcare workers. I thought it was nuts then, and still do.

  3. I agree the science on mandatory flu shots is weak, and also that there is a common sense rationale for such policies nonetheless. Thus, the topic is controversial and different institutions have different policies for employee behavior.

    Similarly, BBE has even weaker evidentiary basis, but a good common sense rationale, therefore analogous to the flu shot debate people arrive at disparate conclusions and institutional practice varies.

    Given the parallels above, it is notable you come down against mandatory flu shots for HCW but for BBE.

    You make a key point above, though: the weaker the data, the more such decisions should be optional. An institution could strongly recommend flu shots, but not mandate them. I'd advocate for a similar approach to white coats: institutions should suggest HCW leave fomites at home but there should be no mandate.

    This begs a key question: how do you assess compliance with or efficacy of an optional intervention?

    1. To be clear, the superficial answer is that rates of a behavior are rates of the behavior whether optional or mandatory. But isn't the natural inclination to get as close to 100% as possible once the rate is being tracked, even if the evidence is (unlike hand hygiene for instance) not strongly in support of such a common sense metric? Thus, our method of tracking could drive institutional metrics that are not aligned with evidence, and ultimately undermine credibility. You could set a sub-100% target of course, but amid such controversy what numerical threshold isn't wholly arbitrary and even arguably absurd. I've to hear how you'd suggest operationalizing.

    2. Mike Edmond asked, why we'd need to assess compliance with an optional intervention. But I thought he had data to show that BBE was around 80% at his old hospital with voluntary policy. You could just watch what folks wear when you do hand hygiene surveillance.

      Two things I find interesting about the response to my posts. First, you and others have assumed I am against influenza vaccine mandates. I don't think I ever said that. I just question the evidence and think there is huge opportunity to learn from them if we fund the right studies. We won't fund the right studies if we think the evidence is strong (which it isn't) Second, you and Mike Rubin above link this to our request to go BBE the elbows. It is possible that I said we should mandate BBE somewhere, but being strongly in favor of BBE is different than a mandate or ban. But to be clear, I am for banning white coats and mandating influenza vaccines but studying both too. Best evidence suggests both policies would be effective. But, I also think the bar should be FAR higher for mandating influenza vaccines (injections and punitive masking) than just ditching the white coat.

    3. Hmm, not suggesting you ever said that we should mandate BBE; I was just attempting to distinguish the difference between two interventions that have been discussed here, each of which makes some intuitive sense but has little evidence to support a policy based on it. One has been argued strongly in its favor (despite the lack of evidence), the other against (because of the lack of evidence). I was asking if the reason for the difference is because one is mandated while the other is not, which appears to be the case.

      I'm not saying I disagree with you -- I am also in favor of banning white coats and ties as well as mandating flu vaccines, and I agree that the bar should be higher for a mandate.

  4. Why do you need to assess compliance for an optional intervention?

  5. We did eventually measure bare below the elbow compliance at VCU but the data weren't used to increase compliance.

    1. Curiosity. It seemed as though over time we were seeing more HCWs that were BBE. The first prevalence survey was done 5 years after roll out.

    2. So if there is an intervention that you believe can reduce infection transmission but is optional or voluntary, there is no reason other than curiosity to measure compliance?

    3. I don't believe that we have to drive every intervention with in-your-face education and feedback, as I think it turns HCWs off and negatively influences the culture. Our approach to BBE was to have a very soft roll-out by giving doctors permission to do it, and some communication through posters. We didn't hassle anyone, and made sure to state that this was not a mandate. We chose to let the behavior diffuse slowly, and it did. And I think the gain in the long-run was much greater. Had we tried a mandate there would have been so much push-back and polarization that no momentum would have ever been gained.

  6. Wow. Such a hot topic in the blog!
    I agree with Eli that there is not enough evidence for mandatory influenza vaccination. However, having experienced both practices (mandatory vs. not), I much prefer the mandatory influenza vaccination experience. Why? Because, I don't have to invest tons of time and effort convincing (or chasing) people to get vaccinated. Magically compliance is 99.9%. (while writing this, it does feel kind of self-centered, but it probably nets as beneficial for our patients).

    1. It is true that we need cost-effectiveness studies - I suspect the time saved on not chasing HCW to get vaccinated could be much better spent on hand hygiene and presenteeism

  7. Not that I'm opposed to the general case made about influenza mandates, but because the philosophy is approximately "no conclusions without data", I think we have to acknowledge that:
    A) Viral shedding (and by extension, infectivity) among influenza-infected individuals with and without prior influenza vaccination may be different, and
    B) We don't know that presenteeism is different among influenza vaccinated and unvaccinated individuals.

    Put differently, I don't know it's fair to assume that influenza-vaccinated individuals would more likely exhibit the moral hazard of presenteeism with the false belief they're protected from all ILI. **If presenteeism rates are the same, I'd rather have mandatory vaccination than not.**

    It's possible (but admittedly unproven) that the culture change that comes with encouraged or mandatory influenza vaccination improves awareness of viral respiratory pathogen transmission more generally and encourages conscientious healthcare worker behavior.

    P.S. Putting the complexity aside--and the issues that social issues that mandates entail--I find the "5-32% vs 48-70%, ergo >50% is not necessarily better" argument non-intuitive and odd (although on it's face, true).
    If the only data we had demonstrated 50% hand hygiene adherence resulted in fewer MDRO acquisition events than 20% hand hygiene adherence, would you argue there's no reason for us to try to achieve >50% hand hygiene because it may be harmful? After all, maybe mandating hand hygiene (and wear gloves if you don't) means people will feel license to touch whatever surfaces in the room/patient and result in more transmission...
    Unless we have some factual basis for believing that >50% vaccination rates results in some harm, I think it's a reasonable assumption that since vaccination prevents illness (with whatever effectiveness--hand hygiene doesn't prevent all MDRO acquisition) higher vaccination rates are of net benefit.
    Now how to get there is a good subject for debate!

    1. Very good points and questions Graham. In regards to the question about 50% vaccination rates, I was just referring to what the data shows in LTCF (i.e. the only data we have). I don't think we should assume that getting vaccination rates above 50% is cost-effective even if we assume the population threshold to achieve herd immunity would be be higher than that level. If I take this a step further, there is really no evidence (confirmed influenza cases) that mandating vaccination of healthcare workers in LTCF or hospitals is effective so debating thresholds and viral shedding is mute at this point. I assume the reason we have no data is because mandates don't work through some countervailing process because clearly the vaccine works for individuals. But, I do think we need trials to figure these things out. Crazy that in 2015 we don't have this data - will be really crazy if we don't have the data by 2020.

  8. Thanks Graham for your comments.
    I'll address your comment: "I don't know it's fair to assume that influenza-vaccinated individuals would more likely exhibit the moral hazard of presenteeism with the false belief they're protected from all ILI. " I agree and have never stated that. The issue is that hospitals have essentially turned a blind eye towards presenteeism and in some cases encourage it. It's much easier to fire HCWs who don't get a flu shot than do the hard work of keeping sick HCWs home. And I think hospital administrators love the mandate because it makes them look like they are taking a strong stand on reducing infections.

    1. I'm not sure I would necessarily say hospitals are encouraging presenteeism, but I think it's pretty clear that many healthcare workers would come to work sick not because of a false sense of protection from the vaccine, but rather because of a strong reluctance to use their sick days. A more effective system for persuading healthcare workers to stay at home when sick is needed, such as designating a certain number of (non-rollover) sick days specifically for influenza (or its vaccination).

    2. Get a group of nurses together and ask how many have been told to come to work anyway when they have tried to call in sick. PTO (as opposed to sick time) is another way that some hospitals encourage presenteeism.

      Here's an old post on a study that evaluated modeling influenza transmission when workers are given flu-specific sick days:

    3. No disagreement that we may be putting the biggest push behind the smallest plow!

      There are other areas where hospitals should lead with "well-being" practices but often aren't, for example:

      ** paid maternity (and paternity) leave
      [why isn't healthcare better represented on this list , e.g. ]

      ** smoking cessation
      [ why aren't there a bunch of 0%s in this study ]

      and getting back to healthcare,
      ** fair wages for the folks who do tough and important work to our infection control mission
      [,_Hospital/Hourly_Rate ]

    4. That has not been our experience with nurses or other staff with respect to being told to come to work despite illness; it has consistently been the reluctance to use sick days or PTO. But it seems that we all agree on the basics of the issue.


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