Hand Washing vs. Hand Sanitizer in the Fight Against Norovirus

Unlike many viruses that need to gang up on a cell by way of a virus cloud, this extremely low infectious dose is paired with how much virus is shed in vomit or diarrhea. It is the perfect infectious storm able to overcome common everyday hand hygiene measures with ease and causing some 20 million cases of norovirus in the US annually and around 600 to 800 deaths. 
 
Consider this, virus particle counts of up to 10 billion per gram of feces have been detected and it has been reported that the same levels can be shed in vomitus during projectile vomiting.  Based on the quantity of fecal material and vomitus shed by an infected person, it is easy to see that there is enough virus shed from one person if spread super-efficiently, to infect practically everyone on the planet.  Some gastrointestinal infections play nice by only being transmitted by hand contact, but with norovirus aerosol transmission is all too common with reports of up to 10 million particles aerosolized in a single forceful up-chuck shot.
 
Not only are public restroom facilities turned into hot spots worthy of avoidance, but during these events ventilation systems become contaminated as well. We have some vivid records of norovirus attacks on food workers where in a 6-hour period, a cake decorator had five episodes of diarrhea and two of vomiting and this is not uncommon.   Needless to say the cakes she decorated were highly infectious.
 
For removal of norovirus (previously termed Norwalk virus or small-round-structured-viruses - SRSV) friction seems to play more of a role than surfactant activity.  We need the surfactants in hand soap to get rid of the soil or in technical terms “filth”.  There are half dozen scientific articles that show friction during the rinsing phase can be particularly effective against similar small viruses including human norovirus surrogates.  The most effective hand sanitizers have been shown to repeatedly do a good job at reducing norovirus counts delivering up to 2 log reduction on hands.  It has been credited as an effective tool in outbreak control, but cannot be relied upon as the primary means of preventing infections.  

This was seen in the studies published in the last few years looking at infection rates in long-term care facilities where too heavy a reliance on hand sanitizers, operating under conditions dependent on part-time staff and low staff to patient ratios combined contributed to outbreaks.   Systematic reviews of interventions also do not identify silver bullets that stop outbreaks in their tracks, but instead show that it is a labor-intensive effort.  When all is said and done, frequency that the intervention is carried out is the most commonly identified characteristic of any of the programs described as working.  A study by Greig and Lee published in 2012 showed that in healthcare facilities restricting the movements of patients and staff, enhanced environmental cleaning and hand hygiene was key.  Shared toilet facilities can literally be a killer, not just for norovirus but for C. difficile as well, another microbial agent even more refractory to hand sanitizer treatment. “ 

This excerpt comes from the debgroup.com and you may read the entire article by Barry Michael’s by clicking here.