(CC-licensed photograph by Flickr user fdecomite)
Comments are still active on my Boing Boing guest blog post from earlier this month about how I haven't used soap or shampoo for over a year. There is much debate in that comment thread on both sides of the argument (to suds or not to suds).
Commenter Emmalish just pointed out this UNC study [pdf] which would appear to back up my beliefs. The report states:
Effective hand hygiene for high levels of viral contamination with a nonenveloped virus was best achieved by physical removal with a nonantimicrobial soap or tap water alone.
Somewhere in the middle, it also states:
Of all the hand hygiene agents, the most efficacious at reducing MS2 was the handwashing with tap water alone, followed by the nonantimicrobial soap handwash, and the 0.2% benzethonium chloride handwash.
In conclusion, our study shows that, at a short exposure time of 10 seconds, all agents with the exception of handwipes and a 60% ethyl alcohol handrub performed similar to nonantimicrobial and tap water controls with reductions of 1.15 to 2.01 log10 of Serratia marcescens. After 10 episodes, which evaluates the efficacy of agents following multiple episodes of contamination, handwashing agents with 0.75% CHG, 2% CHG, 4% CHG, 1% triclosan, 0.2% benzethonium chloride, nonantimicrobial soap hand-wash, and tap water alone were efficacious ($1.5 log10) in reduction of bacteria.
While this doesn't suggest that everyone should go throw out all their soap, it suggests that the idea soap is needed, required, or is playing an active role in keeping some crazy bacterial outbreak at bay is baseless. Using water alone appears to do the trick just fine - not just in my experience, but in the lab as well.