ALCOHOL-BASED SANITIZERS

What is all this fuss about alcohol based sanitizers and people complaining about hike in prices. I am alright with the price of my local gin (Ye bu didi) from the “Blue Kiosk”. I can use it use as my hand sanitizer in light of the scare about the corona virus.

In responding to this enquirer I used a lot of material from the World Health Organization (WHO) guideline on hand hygiene for health care (2009) and Guideline for Hand Hygiene in Health Care Settings of the Centers for Disease Control (CDS). No it is not the same. The local gin is about 40% strength of alcohol (ethanol). Alcohol based sanitizer are required to be 60-80% concentration to be effective. The paradox here is that higher concentrations are less potent because proteins are not easily denatured in the absence of water. Most alcohol-based hand antiseptics contain either ethanol or isopropyl alcohol or a combination of these two products. The antimicrobial activity of alcohols results from their ability to denature proteins.

The alcohol content of solutions may be expressed as a percentage by weight (w/w), which is not affected by temperature or other variables or as a percentage by volume (v/v), which may be affected by temperature, specific gravity and reaction concentration. e.g.  70% alcohol by weight is equivalent to 76.8% by volume if prepared at 15°C, or 80.5%if prepared at 25°C

Alcohols have excellent in vitro germicidal activity against Gram-positive and Gram-negative vegetative bacteria (includingmulti drug-resistant pathogens such as methicillin resistant Staph. aureus (MRSA) and vancomycin resistant enterococci (VRE), M.tuberculosis, and a variety of fungi. However, they

have virtually no activity against bacterial spores or protozoanoocysts, and very poor activity against some non-enveloped(non-lipophilic) viruses.  In the World Health Organization specifications for hand sanitizers’ hydrogen peroxide in incorporated to deal with the spores. In tropical settings, the lack of activity

against parasites is a matter of concern about the opportunity to promote the extensive use of alcohol-based hand rubs, instead of  hand washing, which may at least guarantee amechanical removal effect.

Some enveloped (lipophilic) viruses such as herpes simplex virus (HSV), HIV, influenza virus, respiratory synctal virus (RSV) and vaccinia virus are susceptible to alcohols. Coronaviruses are enveloped viruses. Other enveloped viruses that are somewhat less susceptible, but are killed by 60–70% alcohol, include hepatitis B virus(HBV), hepatitis C virus. In a porcine tissue carrier model used to study antiseptic activity, 70% ethanol and70% is opropanol were found to reduce titres of an enveloped bacteriophage more effectively than an antimicrobial soap containing 4% Chlorhexidine gluconate. In 1994, the Food & Drug Administration (FDA) classified ethanol 60–95% as a generally safe and effective active agent for use in antiseptic hand hygiene or health care workers (HCW) handwash products. Alcohols are rapidly germicidal when applied to the skin.

Alcohols, when used in the specified concentrations in alcohol-based handrubs,  have in vivo activity against a number of non-enveloped viruses, e.g. in vivostudies using a finger pad model have demonstrated that70% isopropyl alcohol  and 70% ethanol were more effective hand medicated soap or non-medicated soap in reducing rotavirus titres on finger pads. Another study using the same test methods evaluated a commercially available product containing 60% ethanol, and found that the product reduced the infectivity titres of three non-enveloped viruses(rotavirus, adenovirus, and rhinovirus).Othernon-enveloped viruses such as hepatitis A and enteroviruses (e.g. poliovirus) may require 70–80% alcohol to be reliablyinactivated (Wolff MH. Hepatitis A virus: a test method for virucidalactivity. Journal of Hospital Infection, 2001, 48(Suppl.A):S18–S22., Mbithi JN, Springthorpe VS, Sattar SA. Comparative invivo efficiencies of hand-washing agents against hepatitis A virus (HM-175) and poliovirus type 1 (Sabin). Applied Environmental Microbiology, 2000, 59:3463–3469.Mbithi JN, Springthorpe VS, Sattar SA.

Comparative invivo efficiencies of hand-washing agents against hepatitis A virus (HM-175) and poliovirus type 1 (Sabin). Applied Environmental Microbiology, 2000, 59:3463–3469).It should be noted that, depending on the alcohol concentration, time, and viral variant, alcohol may not be effective against hepatitis A and other non-lipophilic viruses. The inactivation of naked (nonenveloped) viruses is influenced by temperature, the ratio of disinfectant to virus volume, and protein load.

Alcohols are not good cleansing agents and their use is not recommended when hands are dirty or visibly contaminated with proteinaceous materials. When relatively small amounts of  proteinaceous material (e.g. blood) are present, however, ethanol and isopropanol may reduce viable bacterial counts on hands. This does not remove the need for hand washing with water and soap whenever such contamination occurs.

A systematic review of publications between 1992 and 2002 on the effectiveness of alcohol-based solutions for hand hygiene showed that alcohol-based hand rubs remove organisms more effectively, require less time, and irritate skin less often than hand washing with soap or other antiseptic agents and water (Picheansathian W. A systematic review on the effectiveness of alcohol-based solutions for hand hygiene. International Journal of Nursing Practice, 2004, 10:3–9)

The availability of bedside alcohol-based solutions increased compliance with hand hygiene among HCWs.

DR. EDWARD O. AMPORFUL

CHIEF PHARMACIST

COCOA CLINIC