Hand hygiene doesn't prevent healthcare associated infections

Not all transmission leads to infection and not all infections are preceded by transmission. Hand hygiene prevents transmission, not infection.

....some posts are just hard to write.

One of the persistent beliefs in infectious diseases and infection prevention is that hand hygiene compliance prevents healthcare associated infections. Perhaps this harkens back to Semmelweis and the prevention of puerperal fever through hand disinfection. Of course, if puerperal fever was a CDC HAI and clinicians didn't wear gloves, we could still say hand hygiene prevents HAI. However, that's not the current reality.

CDC defines HAI as CLABSI, CAUTI, SSI and VAP. We can even consider hospital-onset BSI and almost any other infection we can track using CMS or EMR data and monthly aggregate hand hygiene compliance is not a significant component in the causal pathway for the development of an HAI.

Sure, hand hygiene/sterile gloves before catheter insertion and hand antisepsis prior to invasive surgical procedures are standard practice. However, when I talk about hand hygiene compliance, I mean monthly hand hygiene on room entry/exit or following the WHO 5 My 5 Moments during care on medical wards and in ICUs. And yes, there are instances where Moment #2 - before clean/aseptic procedure could potentially reduce CLABSI, but the proportion of CLABSI caused by such breaks in moment #2 pale that occur outside of the insertion bundle pale in comparison to those prevented with the highly effective CLABSI bundle. Otherwise, monthly aggregate hand hygiene compliance would have been included in the CLABSI bundle. It wasn't.

Let's discuss SSI prevention. Do we really think that interns and nurses practicing hand hygiene on the wards prevents SSIs to any measurable extent compared to pre-operative CHG bathing or peri-operative antibiotics?  No, I didn't think so.

How about we look at this another way. If you were called by a CT surgeon because of an outbreak of SSI in CABG patients or an outbreak of CLABSI in her ICU, would you first (or second or third) start a hand hygiene campaign? I assume no and thus, you don't think hand hygiene prevents SSI or CLABSI. 

Thus, for all practical purposes, we won't be able to do studies associating improved hand hygiene compliance on the wards or ICUs with reduced infections. Even when such studies are done and do show an association, they have minimal basis in causal reality. Requiring hand hygiene bundles and intervention studies to show reduced HAI is incorrect and counterproductive. Since hand hygiene on wards and ICUs is not in the causal pathway for HAI incidence, we shouldn't expect hand hygiene to prevent them.

But all is not lost. Hand hygiene does prevent MDRO transmission (and indeed transmission of susceptible pathogens) in healthcare settings. Hand hygiene is critical to tackling the MDRO crisis but these benefits aren't currently captured by CMS and most EMR systems. To document the benefits of hand hygiene, we would need to complete surveillance for important pathogens on admission and discharge and document acquisition or transmission. This is expensive and likely not necessary nor feasible.

Keep your heads up and continue to drive hand hygiene compliance. Continue to do hand hygiene surveillance and improvement studies! Hand hygiene is critical to MDRO prevention and likely the future of healthcare. Just stop it with the HAI target.

Addendum: This post was written in response to the question: "Do you care about increases in monthly hand hygiene compliance if you can't document reduced HAI?" I would answer yes. Hand hygiene is an important clinical outcome in itself and requiring HAI reductions is a trap. Don't fall into that trap. I've attempted to explain why here.

Addendum 2: In response to this post, others have mentioned CDI as an HAI that could be targeted with hand hygiene interventions. As Dan mentioned back in 2013, CDI might not be the optimal target since a minority of cases appear to be related to in-hospital transmission. This was shown back in 1994. Stewardship might be a more appropriate intervention for CDI prevention.


  1. Dear Eli,
    I read your twitter and found your blog here. May I have a question please?
    Why do you consider other infection except CLABSI, CAUTI,VAP,SSI, and hand hygiene compliance are not significant component in the causal pathway for the development of an HAI?

  2. Hey Eli,
    Provocative piece that I find interesting.
    I've always been impressed by the fervency around hand hygiene.
    What do you fin dare the most impressive studies showing it has an impact on transmission? I know it should theoretically but don't know of many clinical studies showing this.
    Take care,

    1. Excellent question. I would start with a causal diagram, knowledge of causal relationships - like when you say "it should theoretically" and then apply your knowledge of correlations along the causal pathway. I'm not sure you will find that knowledge in an RCT, which is perhaps what you are implying by clinical studies. I'm quite sure you can't answer your question in one study, but perhaps it would take several or many studies. I'm convinced that if we model hand hygiene correctly with data such as this: https://www.ncbi.nlm.nih.gov/pubmed/20486855 , we can then see that hand hygiene prevents MDRO transmission.

      Happy to discuss further, perhaps in a future post. If you are looking for an RCT that measures transmission of 20 MDRO (KPC, NDM-1, OXA-48, MRSA, VRE, etc) of interest using admission and discharge surveillance cultures in settings with and without hand hygiene (or increasing rates of hand hygiene), I don't think that data exists. It likely shouldn't exist (unethical, ridiculously expensive).

      A rhetorical question: What RCT proves the earth revolves around the sun and if none exists, what sort of data, studies, causal diagram could get us the answer? That's how I think about HH and MDRO (and also HH and HAI)

      Probably not the answer you wanted, but this is how I think about infection control questions or at least how I think they can be answered.


  3. Of Course the other important rationale for hand hygiene is to prevent transmission of C diff and resistant bacteria. That aspect is not mentioned in E. Perencevich's essay. Please continue to wash hands!

    1. Hello Bob. Of course I wrote: "Hand hygiene does prevent MDRO transmission" in my essay and specifically addressed CDI in an addendum I wrote a day later on August 15th. Please read my essay and of course wash your hands!


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