Hand Sanitizers: Useful or Not?

There are many things we all can do to keep ourselves healthy, eating a diet rich in fruits and vegetables, getting enough sleep, drinking enough water, the list goes on. One important part to avoiding colds and flus is minimizing unnecessary exposure to microbes that can potentially lead to illness. This is the reason why we put so much emphasis on hand washing and hygiene because these practices have been very useful in decreasing the incidence of disease.

One of the early pioneers for sanitization practices was a German doctor by the name Ignaz Semmelweis. Dr. Semmelweis noticed that when hands were washed in obstetrical clinics regularly the incidence of puerperal fever was drastically reduced. Normally, puerperal fever carried a 10-35% mortality rate among mothers in the mid 19th century. Due to his diligent efforts and others of that time period, hand washing practices became common place over time.

Another practice that has drastically increased is the use of various disinfectants and sanitizers. You can’t go into a hospital without coming across several alcohol disinfectant dispensers. Some people even make it common practice to carry bottles or wipes of alcohol based disinfectant in their purses or cars just in case. However, are they actually as effective as we think they are at dealing with microbes?

Sterilization vs. Disinfection
First, let’s get some terms straight. Sanitizing or sterilizing is not the same as a disinfectant. Both procedures do destroy bacteria, viruses and fungi but not to the same extent. According to the CDC (Center for Disease Control), sterilization is defined as, “Any item, device, or solution is considered to be sterile when it is completely free of all living microorganisms and viruses. The definition is categorical and absolute (i.e., an item is either sterile or it is not).”

Whereas disinfection is defined as, “…less lethal process than sterilization. It eliminates nearly all recognized pathogenic microorganisms but not necessarily all microbial forms (e.g., bacterial spores) on inanimate objects. Disinfection does not ensure an “overkill’’ and therefore lacks the margin of safety achieved by sterilization procedures.” (CDC).

Understanding the difference between these terms is important because the types of cleaners and other products we use to achieve cleanliness are of varying strengths on the disinfectant spectrum. Due to the harshness of sterilization methods it’s not possible to sterilize people. Also remember there are ‘good’ and ‘bad’ bacteria, and we need the good bacteria to survive. If all forms of bacteria were wiped out from our bodies we would actually be susceptible to infection by the bad bacteria.

Classes of Disinfectant
When we’re discussing what kinds of things are good to use for cleaning and keeping ourselves healthy we need to think about the level of disinfectant needed. Disinfectant products are categorized from high to low disinfectant properties. They are defined as follows:

High disinfectant: This procedure kills vegetative microorganisms and inactivates viruses, but not necessarily high numbers of bacterial spores. Such disinfectants are capable of sterilization when the contact time is relatively long (e.g., 6 to 10 hours). As high-level disinfectants, they are used for relatively short periods of time (e.g.,10 to 30 minutes). These chemical germicides are potent sporicides and, in the United States, are classified by the FDA as sterilant/disinfectants. They are formulated for use on medical devices, but not on environmental surfaces such as laboratory benches or floors.

Intermediate disinfectant: This procedure kills vegetative microorganisms, including Mycobacterium tuberculosis, all fungi, and inactivates most viruses. Chemical germicides used in this procedure often correspond to Environmental Protection Agency (EPA)-approved “hospital disinfectants” that are also “tuberculocidal.” They are used commonly in laboratories for disinfection of laboratory benches and as part of detergent germicides used for housekeeping purposes.

Low disinfectant: This procedure kills most vegetative bacteria except M. tuberculosis, some fungi, and inactivates some viruses. The EPA approves chemical germicides used in this procedure in the US as “hospital disinfectants” or “sanitizers”.

To help you understand what kinds of chemicals and products are categorized under each of these subheadings, take a look at the following table:

Activity Levels of Selected Liquid Germicides

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Procedure/Product
Sanitization

glutaraldehyde

Hydrogen peroxide

formaldehyde

chlorine dioxide



Disinfection

glutaraldehyde

ortho-phthalaldehyde

hydrogen peroxide

formaldehyde

chlorine dioxide

peracetic acid

chlorine compounds

alcohols (ethyl, isopropyl)

phenolic compounds

iodophor compounds




Quaternary ammonium compounds

Aqueous Concentration/Activity Level

 
variable

6 – 30%

6 – 8%

variable





variable; high to intermediate

0.5%; high

3 – 6%; high to intermediate

1 – 8%; high to low

variable; high

variable; high

500 to 5000 ml/L free/available; intermediate

chlorine; intermediate

70%; intermediate to low

0.5 to 3%
30 – 50 mg/L free iodine up to
10,000 mg/L available iodine
0.1 – 0.2%; intermediate to low

low

As you can see the sterilization agents kill everything, but the disinfectant agents have a great deal of variability. Probably the two you’re most familiar with are the hydrogen peroxide and alcohols (ethyl and isopropyl). The hydrogen peroxide and alcohol people typically use would be in the intermediate category at best. So they do help to kill off most organisms, but not all of them. The CDC also mentions that the effectiveness of alcohols is limited, “…they evaporate rapidly, resulting in short contact times, and also lack the ability to penetrate residual organic material. They are rapidly tuberculocidal, bactericidal and fungicidal, but may vary in spectrum of virucidal activity. Items to be disinfected with alcohols should be carefully pre-cleaned then totally submerged for an appropriate exposure time (e.g., 10 minutes).”

Should We Use Hand Disinfectants?
So this all comes down to whether it’s worthwhile to use such products as ethyl alcohol hand disinfectants, or if we should just be washing our hands a lot more. As we’ve seen, the alcohol and other such products can be useful to eliminate bacteria, but not completely. So it is certainly better than using nothing at all, but definitely the more effective method is actually washing your hands with soap and water. They should be used as a complimentary measure as opposed to a replacement for hand washing. There are also natural alternatives to alcohol-based products that use plant essential oils and no additional chemicals. These natural products are a nice alternative because essential oils are plants natural defense mechanism against bacteria and are less likely to react with sensitive skin. One example of a product is Clean Well, which is alcohol, paraben and triclosan free. Ultimately, the choice is yours to make. If you do choose to use an alcohol-based disinfectant, make sure it’s at least 70% ethyl or isopropyl and it does not contain any additional chemicals.



References:
CDC. Biosafety: Appendix B – Decontamination and Disinfection. http://www.cdc.gov/biosafety/publications/bmbl5/bmbl5_appendixb.pdf
Clean Well. All the Facts. http://www.cleanwelltoday.com/a-better-way-to-clean/all-the-facts/
Disinfectant vs Sanitizers. University of Hillyard. http://www.hillyard.com/ProductsServices/UniversityofHillyard/Disvsant.htm
Semmelweis Society International. Biography of Ignaz Philipp Semmelweis. http://www.semmelweissociety.org/Biography.aspx