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Thursday, January 15, 2009

Hand Sanitizers Battle The Common Cold: Expert Says: Alcohol Hand Sanitizers PROMOTE transmission of Common Cold (Rhinovirus)

According to J. Owen Hendley, a professor of Pediatric Infectious Disease at UVA Med, alcohol-based hand sanitizers are no good for cold prevention.

Flu, yes, but rhinovirus (yer common cold bug) apparently kinda likes booze. Dr. Hendley’s put out a lot of interesting, if icky, stuff on rhinovirus, and is something of a go-to expert on the subject

From the study: " ..It should be noted that 62% ethanol, contained in many commercial hand sanitizers, is also ineffective for complete removal of rhinovirus from the hands and would be expected to be ineffective for the prevention of rhinovirus infection..."

Certain acids (such as malic and citric acids) can also be helpful. Either way, next time you’re Purell-ing up, don’t think it’s as good as washing with soap and hot water, despite what the NIH says.

Another extract:

TURNER RB, WATSON DD, KESWICK B, BIEDERMANN KA, ERTEL KD, LEVINE MJ, MORGAN JM, MARIC A, BARKER MF; Interscience Conference on Antimicrobial Agents and Chemotherapy (41st : 2001 : Chicago, Ill.).

Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 2001 Dec 16-19; 41: abstract no. H-660.

Medical University of South Carolina, Charleston, SC

Direct hand-to-hand contact is an important mechanism of transmission of rhinovirus infection. Two randomized double-blind studies of antiseptic hand cleansers for prevention of transmission of rhinovirus were done. In both studies, the hands of volunteers were contaminated with 100 TCID50 of RV at defined times after use of the hand cleanser. Ten minutes after application of the virus the volunteers made intentional contact between one contaminated hand and the conjunctiva and nasal mucosa and quantitative viral cultures were done on the other hand. Volunteers were monitored for development of infection by culture and serology. The first study (85 subjects) compared active preparations containing either 3.5% salicylic acid (SA) and 62% ethanol (EtOH) or 1% SA, 3.5% pyroglutamic acid (PGA) and 62% EtOH with a control of 62% EtOH. Hand challenge with virus was done 15 minutes after treatment with the cleanser. In the control group, 28/31 (90%) had positive hand cultures and 10/31 (32%) developed infection. In contrast, 4/27 (15%) and 0/27 had positive hand cultures in the 3.5% and 1% SA groups, respectively (p<0.05). Infection developed in 2/27 (7%) of volunteers in both treatment groups (p<0.05 compared with control).

The second study (122 subjects) evaluated a hand wipe containing 4% PGA + 0.1% benzalkonium chloride.

Hand challenge was done 15 minutes, 1 hour, and 3 hours after treatment. Significantly fewer volunteers had positive hand cultures at all time points compared with the control group. These results suggest the feasibility of prevention of RV transmission by hand treatments that are virucidal on contact and have activity that persists after application.

What's the answer?: Many of the studies have concluded that iodine-centric products are actually the most effective in terms of killing rhinovirus. Iodine is also effective i.e. norovirus.
That said, wiping your hands with iodine has obvious down-sides and side effects.

The conclusion? If opting for a hand sanitizer product; why would you use an alcohol-based gel vs. those that use benzalkonium chloride as the active ingredient??

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