From the Research
Unwashed hands typically carry a bacterial count of around 1.65 log(10) as found in a study of healthcare workers 1. This number can vary significantly based on individual activities and environments. The bacterial count is generally higher in areas like fingertips, under fingernails, and between fingers where moisture and skin oils create favorable conditions for bacterial growth. Common bacteria found on hands include Staphylococcus, Streptococcus, E. coli, and various other environmental microorganisms. This bacterial load increases substantially after using the bathroom, handling raw food, touching public surfaces, or spending time in healthcare settings. Some key points to consider about hand hygiene include:
- Regular handwashing with soap and water for at least 20 seconds can reduce the bacterial count by 90% or more, which is why proper hand hygiene is considered one of the most effective ways to prevent infection transmission.
- When soap and water aren't available, alcohol-based hand sanitizers containing at least 60% alcohol can serve as an effective alternative, though they may not eliminate all types of germs and are less effective on visibly dirty hands.
- A study from 2017 found that the bacteria released from female washed hands in wet and dry conditions was lower than from male's hands, with a significant difference of 3 CFU vs. 8 CFU; confidence interval 95%, P ≤ 0.001 2.
- Another study from 2018 found that the World Health Organization's 6-step hand hygiene technique was effective in reducing the microbial load on the hands of healthcare workers, but the evidence was not strong enough to identify it as the most effective technique 3.
- The most recent and highest quality study on this topic is from 2018, which provides the best evidence for the effectiveness of hand hygiene techniques 3.