I posted recently on the potential risk of CPE contamination of sinks, drains, and hospital wastewater. The question in my mind then was whether contamination is a smoking gun or innocent bystander regarding CPE transmission? What we really need is an intervention to show that better management of sinks and drains results in reduce CPE transmission. And now, we have one! The findings suggest that attempts to control CPE will go down the drain if we don’t intervene to improvement the management of sinks and drains.
We have blogged before how CAUTI is rather ‘unloved’ as an HCAI prevention target. CLABSI reduction, on the other hand, is all the rage. Now, there is a key reason why this makes sense: outcome! A CLABSI is much worse news for a patient than a CAUTI. However, this doesn’t mean we should turn a blind eye to CAUTI, especially since CAUTI is a common root cause for CLABSI! In the US there is an addiional driver for preventing CAUTI: the costs associated with CAUTI are no longer reimbursed by insurers (since 2008). With this in mind, it was great to see a CAUTI reduction study published in NEJM recently (and see some interesting analysis on the Controversies blog).
I am no expert in HIV, but I know that ‘vertical transmission’ means something very specific:
Vertical transmission: the transmission of a disease from mother to child either during pregnancy, childbirth, or by breastfeeding.
Similarly, the definition of ‘horizontal transmission’ is well defined:
Horizontal transmission: the transfer of an infection from person to person.
So, when I read about ‘vertical’ and ‘horizontal’ interventions in a recent New England Journal of Medicine Editorial and the Controversies blog, I began to get a little confused. I have a PhD in epidemiology so don’t consider myself easy to confuse (in this particular domain), but I would have thought that a ‘horizontal intervention’ would be directed towards preventing horizontal spread of an infectious agent and a ‘vertical intervention’ would be directed towards preventing the vertical transmission of an infectious agent. But this is not how these terms are being applied. Instead, a ‘horizontal intervention’ is being used to describe an intervention applied to every patient (such as chlorhexidine bathing or hospital-wide hand hygiene interventions) whereas a ‘vertical intervention’ is being used to describe an intervention designed to reduce colonization or infection due to a specific pathogen (such as active screening and isolation to prevent the spread of MRSA). The use of the term ‘vertical intervention’ seems especially confusing, since it’s a ‘vertical intervention’ to prevent the horizontal transmission of a specific pathogen!
I fail to see how the terms ‘vertical’ or ‘horizontal’ intervention are useful when there are such well-established definitions for horizontal and vertical transmission. I think that ‘universal intervention’ (such as universal screening or decolonization) and ‘targeted intervention’ (such as active screening and isolation to prevent the spread of MRSA) make a lot more sense. These terms are already in common circulation, so I would urge those who favour the use of ‘vertical’ or ‘horizontal’ intervention to reconsider their terminology.