Hand washing: is near enough good enough?

Anne Little 

MORE hand washing doesn’t result in a corresponding reduction in hospital-based infections, according to research from the United Kingdom. 

In health care, hand washing is touted as the panacea for eliminating nosocomial infections. Despite the convention that hand washing alone can reduce hospital based infections, a combined University of Bradford and Harrogate District Hospital study has found that increasing the frequency of hand washing by health care workers does not lead to commensurate reductions in staphylococcal infection in a hospital ward.

Co-author and Department of Microbiology professor at Harrogate and District National Health Service Foundation Trust, Kevin Kerr, said the assumption that hand washing could prevent all hospital care-acquired infections (HCAI) had led to the research.

“There is a perception by some healthcare regulators that the problem of HCAI has been largely created by healthcare professional not washing their hands,” he said.

“There is also a perception that increasing hand hygiene rates to as close to 100 per cent as they can get will solve the problem.”

The study, headed by UB professor of medical technology, Clive Beggs, aimed to evaluate the impact of hand-washing technique and frequency on the transmission of staphylococcal infection and identify if there is a limit at which further compliance would not show results.

The results published online in the journal BioMed Central Infectious Diseases revealed that while hand hygiene is an effective control measure, the laws of diminishing returns apply.

When it comes to hand washing, the most benefit is seen in the first 20% of compliance. The researchers concluded there is little benefit in a 100% rate of hand-washing compliance and a compliance rate of more than 40% should be enough to prevent outbreaks of staphylococcal infection.

While the frequency of hand washing in relation to HCAI has previously been researched, the team said they consider hand washing to be an imperfect process. 

The ability of hand washing to limit hospital-based infection depends on the products and technique used, and the duration of the washing. 

The amount of hand washing needed also plays a part in compliance, with previous studies suggesting health workers may need to wash their hands up to 43 times per hour, leading to a compliance rate of less than 50%.

In generating the results, the researchers used a model to determine the effectiveness of hand-washing frequency on HCAI rates from a previous study, which they modified to include the impact of the efficiency of hand washing. 

They also considered the impact of washing with soap and water and the use of alcohol hand gels.

Within the model, the researchers made a number of assumptions, including that transmission is caused by colonised hand contact and health care workers pick up the contamination when they touch a colonised patient. 

It was also assumed that it is just as easy for a patient to contaminate a health worker as it was for the health worker to contaminate the patient.

While the team acknowledged their results could only approximate what happens in clinical practice, they felt it was useful in identifying general trends in infection control, especially if the ward conditions mirrored the research model.

According to the researchers, the study confirmed that hand washing is an effective infection control measure, but laws of diminishing returns apply with the greatest benefit seen in the first 20% of hand-washing compliance. 

The results also indicated that there is little benefit in very high levels of compliance. 

Other infection factors

In the discussion, the team indicated many staphylococcal outbreaks could be prevented through moderate levels of hand washing, however, there are four reasons why this might not happen. 

Ward management issues such as overcrowding and under-staffing may play a role in infection rates. The number of patients admitted with the infection can also increase the risk of an outbreak. Also, environmental factors can play a part as inanimate objects can support infection.

The researchers also raised the issue of the Hawthorne Effect, which indicates people can change their behaviour when they are being observed, so what researchers observe may not reflect the reality of what happens on the ward.

Not just staph

While the study referred to outbreaks of staphylococcal infections in study, Prof Kerr is confident the results can apply to other infections as well.

“It is not unreasonable to extrapolate the research to other HCAI-causing bacteria whose route of transmission is primarily via the hands of health care workers,” he said.

Hand washing training

To combat the risk of HCAI, Prof Kerr identified a need for health care workers to be trained in hand-washing technique.

“Frequency of hand washing is obviously important,” he said.

“Ensuring that health care professionals cleanse their hands effectively is just as significant.

Multi-faceted approach needed

While hand washing is an important infection control measure in health care settings, Prof Kerr cautions health carers not to rely on it solely.

“HCAI is a universal problem and the fundamental issue is the same [on different wards],” he said.

“Hand hygiene, although a crucially important infection control measure, should not be seen as the sole intervention.

“A multi-faceted, coordinated approach is needed in preventing HCAI.

“But if you are going to wash your hands, you need to do it properly.”




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