Alchol-based hand sanitzers aren’t really effective against noro, but here’s the rub

Winter is the hottest time for hospitals, retirement residences, cruise ships and restaurants when it comes to norovirus outbreaks. Here in North Carolina, the Department of Public Health distributed a press release referencing recent outbreaks that has made the rounds on local TV and in small town papers.

With as little as just a few virus particles needed for infection and a high rate of secondary illnesses, a noro problem can escalate quickly (just ask Heston Blumenthal).

And everyone is looking for quick solutions to replace handwashing with soap and water, including the ever-present alcohol-based hand sanitizer. They just don’t exist.

Recent research, the first to evaluate alcohol-based hand sanitizers against a human strain of norovirus, shows that the squirtable and ubiquitous-in-public liquid isn’t a magic bullet. A report in the January Applied and Environmental Microbiology (76:394-399) by Liu et al demonstrates that commonly available alcohol-based sanitizers are less-than ideal against noro (despite many of the sanitizer producers proclaiming magic with Tom-Cruise-on-Oprah’s-couch-like exuberance).

As David C. Holzman of the American Society for Microbiology’s Microbe says:

Moe, Liu, and their collaborators (including my friend Lee-Ann Jaykus) compared the effectiveness of liquid soap and alcohol hand sanitizers in removing or killing viruses on finger pads, following methods developed by the American Society for Testing and Materials.

After finger pads were inoculated with norovirus and then washed, the researchers used quantitative reverse transcriptase PCR to measure viruses that remained. In another set of tests, sodium hypochlorite (bleach) eliminated virus, while ethanol, regardless of concentration, did little to reduce virus titer. In vivo rinsing either with water or with antibacterial, triclosan-containing soap proved about equally effective in reducing viruses on finger pads.

These results suggest that protection comes from mechanically removing the virus from the hands, rather than from inactivating the virus, says Stuart Levy of Tufts University in Boston, Massachusetts.

Here’s the rub (no pun intended): sanitizer alone isn’t even close to being effective as handwashing on noro but what happens in systems (like kitchens) where handwashing compliance is consistently shown to be less than 20 per cent (and other pathogens also exist). In a study we completed, to be published soon, we report that handwashing attempts can be close to zero at busy times. Best practice, until a better option is found is, soap and water but, as barfblog-favorite Don Schaffner has suggested, there might be a public health benefit by providing sanitizer in low-handwashing compliance situations as replacements for handwashing.

This entry was posted in Norovirus by Ben Chapman. Bookmark the permalink.

About Ben Chapman

Dr. Ben Chapman is a professor and food safety extension specialist at North Carolina State University. As a teenager, a Saturday afternoon viewing of the classic cable movie, Outbreak, sparked his interest in pathogens and public health. With the goal of less foodborne illness, his group designs, implements, and evaluates food safety strategies, messages, and media from farm-to-fork. Through reality-based research, Chapman investigates behaviors and creates interventions aimed at amateur and professional food handlers, managers, and organizational decision-makers; the gate keepers of safe food. Ben co-hosts a biweekly podcast called Food Safety Talk and tries to further engage folks online through Instagram, Twitter, Facebook, YouTube and, maybe not surprisingly, Pinterest. Follow on Twitter @benjaminchapman.