In her latest blog, Dr Evonne T Curran discusses how hand hygiene is not, and cannot be, the single most important way to prevent nosocomial transmission and infections
You cannot reason a person out of a position he did not reason himself into in the first place… (Jonathan Swift)
I find this quote disturbing. It suggests that people cannot be persuaded that errors are present even with abundant data because those in influential positions are dismissive of data if they arrived at their flawed positions either via their own misinterpretations, or the misinterpretations of others. So, how does one persuade those in influential positions, without using abundant evidence? One cannot appeal to a higher authority – they are the higher authority. I have acted since 2021 to get recognition that the mode of respiratory transmission as advocated by the WHO and national infection prevention and control manuals (NIPCMs), was as the aerosol scientists determined – defying physics. The responses from those in influential positions – despite abundant data – was woeful, unsafe, dismissive, unconcerned…. I could go on.
In a long career in IPC, many new infection related risks were recognised, in none that I can recall, e.g., Legionnaires disease, vCJD, HIV, Hepatitis B, MRSA, C. difficile, was the recommended action a shoulder shrug. Preventative action was always taken. (I even remember the threat of prison if CEOs failed to reduce MRSA bacteraemia). When IPC erroneously considered there to be just 3 airborne infections (TB, measles and chickenpox), it was easy to recommend isolation and respiratory protection. Now that all viral respiratory infections are evidenced to cause infection by inhalation, IPC and their professional societies are outrageously silent. Sometimes an acceptable solution must arrive before a problem is acknowledged as a threat, e.g., up until the 1970s blankets were shared – because they shrunk in the wash and could not be decontaminated any other way. It took the invention of blankets which could be washed at high temperatures before this risk was negated. Perhaps they are awaiting a cost neutral innovation before advocating to negate the airborne risk?
Grant advises to avoid decision-making based on a dislike of an outcome. And that is what I think is happening. Recognition of airborne transmission of many pathogens will cost money and be uncomfortable for HCWs. [Forget the harms being caused to patients and HCWs]. There is ongoing nosocomial SARS-CoV-2 transmission, infection and secondary consequences which are far graver, if more silent, that the outcomes of the infection risks discussed above. However, it gets worse for IPC. This is because their theory that hand hygiene is the single most important mode of nosocomial transmission and HCAI can be disproved….
Having abundant data on airborne transmission, presenting it to those who failed to reason and change guidance, I went looking for other data and intelligence that might help those in IPC influential positions reason there is a need to start again. Surprisingly, it was not hard to find.
IPC professionals are directed to focus on the implementation of guidance, to minimise healthcare worker (HCW) hand contact transmission. This is in support of the theory that “transmission of microorganisms from the hands of healthcare workers is the main cause of nosocomial infections and handwashing remains the single most important preventative measure”. Over time handwashing has become hand hygiene but the theory remains extant. In 2021, the World Health Organization (WHO) stated (without citations) “The scientific evidence overwhelmingly demonstrates that appropriate hand hygiene is the single most effective action to stop the spread of infection, while integrated with other critical measures.” If the theory is incorrect, then the primary focus of an entire profession is being misdirected. An indication that evidence to support the theory was sparse arose in 2022 when the WHO used two citations [Zhu et al 2021 & Buetti et al 2021] that omit any mention of hands in support of “…hand hygiene has been highlighted as the most effective single measure to reduce the transmission of microorganisms / pathogens and infection in healthcare settings.”
The WHO hand hygiene guidelines include an evidenced theory of how HCW hand contact transmission arises. However, this excludes mechanisms whereby transmission leads to HAI. Yet, if most HAI are evidenced to result from phenomena other than HCW hand contact transmission, then hand hygiene cannot be the most important measure to prevent HAI. The theory would be disproved.
Taking data from the 2024 European prevalence survey 86% of all HAI surveyed arose in 5 categories:
LRTI includes ventilator associated pneumonias (VAP), non-VAP, and respiratory viruses. Most VAP and non-VAP arise from micro- and bolus-aspiration of the patients’ own respiratory flora. Guidance on prevention omits mention of hands and hand hygiene. Most respiratory virus transmission, e.g., from SARS-CoV-2 and influenza, arises following inhalation. Thus, most LRTI are unrelated to hand hygiene.
Most microorganisms causing SSI are from the patient’s own flora. The surgical team can also be a source as their microorganisms are shed into the air during the operation. Ward-based hand hygiene is not a significant factor. The surgeon’s hands still need ‘scrubbed’, and HCWs hands must be clean when touching a patient but this cannot prevent microorganisms from patients causing SSI. Sterile instruments and theatre ventilation are key to SSI prevention.
CA-UTI comprise 62% of all UTI. The most common source of all UTIs are the patients’ endogenous gut flora. Hospital pathogens also cause UTI entering via the drainage system – including via contaminated HCW hands. Thus, prevention involves hand hygiene. The most important infection-provoking factor is duration of catheter usage; early catheter removal being the most important prevention measure.
Roughly a third of BSI, are of unknown origin . Of the remainder, another third arises secondary to a existing primary infection, i.e., unrelated to hands. CR-BSI make up the final third. The causal microorganisms of CR-BSI are mainly from the patient’s own skin. These microorganisms migrate along the catheter lumen forming biofilm from which bits eventually slough off into the blood causing symptoms. Pathogens may be translocated from the gut (also unrelated to hands). Contaminated infusates arise from contaminated environmental splashes during drug preparation, use of contaminated vials or from contaminated hands. Thus, maintaining the sterility of equipment and infusates, using antiseptics to reduce skin organisms at the insertion site (and pre hub access), removing devices as soon as clinically indicated are at least as important as HCW hand hygiene for the BSI unrelated to a secondary source.
Most nosocomial GII are caused by C. difficile and norovirus. A review of C. difficile transmission via HCW hands concluded it may have an ‘important role’. However, recent work on transmission for both pathogens has indicated a previously unrecognised transmission route – aerosol dissemination of the pathogens (and spores for C. difficile) into the environment. Infection in this case arises after inhalation followed by ingestion. Aerosolised pathogens also settle to contaminate the environment and transmit via patient or HCW hand-to-mouth contact. Therefore, although HCW hand contact transmission is important, there is insufficient evidence to suggest HCW handwashing is the most important measure: other factors vying for this role include antibiotic stewardship (C. difficile), aerosol reduction during toilet flushing, environmental hygiene, isolation of symptomatic patients and patient hand washing.
Thus, in none of the most prevalent HAI categories is hand hygiene to avoid HCW hand contact transmission the single most important infection-preventing factor. The theory is disproved; and the entire profession continues to be misdirected and to misdirect.
We will never get nosocomial transmission and HCAI to its irreducible minimum with erroneous, or omitted altogether, modes of transmission. Those in IPC and their professional organisations have an epistemic responsibility to ensure the modes of transmission (including airborne dissemination) are complete and evidenced.
Is this reason enough to start a new conversation about improving safety for people in healthcare?
NB at no point in this blog do I suggest that hand hygiene is unimportant. It is important – but it’s just not No 1.
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