Re-visiting contact precautions – 25 years on

In a recent attempt to conduct a systematic review for evidence for the efficacy of contact precautions in preventing the transmission of respiratory viruses of concern, no evidence was found. Understandably, in the early days of the COVID19 pandemic when there was little information about routes of transmission and high levels of concern, a full range of precautions were applied including contact precautions (CP). However, the legacy of this approach needs careful evaluation in the context of widespread unsafe use of personal protective equipment (PPE), and significant transmission of both SARCoV-2 and other pathogens during the pandemic. There is a danger that CP is perceived as the best ‘precautionary’ approach to minimising transmission of infection with scant regard for evidence for its efficacy or consideration of the rationale and risks associated with it. The term ‘contact precautions’ was first used by the Healthcare Infection Control Practices Advisory Committee (HICPAC) in a guideline on isolation precautions published in 1996. This guideline introduced the concept of Standard Precautions (SP), which was designed to reduce transmission of organisms by direct and indirect contact in all areas of healthcare. In applying these principles in the care of all patients, it enabled many diseases or conditions to be managed without additional precautions. By making this a standard approach for all patients, specific additional precautions for infections spread by contact with blood and body fluid became redundant. In addition to Standard Precautions, Garner (1996) recommended using CP for ‘specified patients known or suspected to be infected or colonized with epidemiologically important microorganisms that can be transmitted by direct contact with the patient (hand or skin-to-skin contact that occurs when performing patient-care activities that require touching the patient’s dry skin) or indirect contact (touching) with environmental surfaces or patient-care items in the patient’s environment’. CP was suggested for use with infections deemed to be of ‘special clinical or epidemiological significance’ (either locally or nationally), those where skin contamination was likely e.g. impetigo or some infections in infants, and infections such as C. difficile where prolonged environmental survival was possible. This guidance was not based on the standards of systematic evidence review that would be expected today. Recommendations were categorised as ‘strongly recommended’ if ‘reviewed as effective by experts in the field and a consensus of HICPAC on the basis of strong rationale and suggestive evidence, even though definitive scientific studies have not been done. ’ The concept of CP remained the same when the guideline was updated and again was not subject to systematic review of epidemiological evidence of need or efficacy. Recommendations were based on ‘theoretical rationale’ and whilst evidence for problems with adherence was considered, recommendations for strategies to improve adherence were not included (Siegel et al, 2007). There is a clear inconsistency in applying a routine standard of care to minimise transmission of pathogens by direct and indirect contact (SP) whilst at the same time designating additional precautions (CP) for organisms deemed to be ‘epidemiological significant’. As Jackson and Lynch pointed out at the time CPwere conceived, this implies that SP are not adequate for reducing the risks of contact transmission for any organisms (Jackson and Lynch, 1996). Most pathogens can be spread by contact of one sort or another, with the extent to which they contaminate the environment related to the nature of the patient’s illness and the ability of the pathogen to survive for prolonged periods on surfaces. This is precisely why SP incorporates decontamination of equipment, the environment and hands as critical to interrupting transmission, and also includes consideration of patient placement (Siegel, 2007). The imprecise definition of why a specific pathogenmaymerit CP has led to it being applied widely with a lack of clarity about what the additional precautions are aimed at, or likely to achieve. In some examples of transmission-based precautions (Scottish National Infection ControlManual, 2021) a wide range of organisms are deemed to be transmitted by contact and require single room accommodation with CP. These include infections for which