A hand rub is a gel or liquid containing antimicrobial agents that decrease the number of microorganisms present on hands. The antimicrobial agents in most hand rubs are alcohols (ethanol, isopropanol, and n-propanol), available in varying concentrations. Because hand rub does not remove organic material, it cannot be used if hands are visibly soiled. Hand rub is sometimes called a sanitiser.
Ethanol, at a concentration of 60% or greater, is effective against:
- Most bacteria – including multidrug-resistant bacteria such as MRSA
- Some viruses, such as influenza virus, herpes simplex virus, rotavirus, and HIV. Hepatitis viruses and enteroviruses may require a higher concentration of alcohol to be reliably inactivated.
Alcohol-based hand rubs have limited effectiveness against bacterial spores (eg, Clostridium/Clostridioides difficile), protozoan oocysts, and certain viruses.
Regular household soap
Social handwashing with non-antiseptic household soap removes bacteria and viruses by physical/mechanical means. Household soap acts as a detergent to help remove loosely adherent bacteria and viruses; microorganisms are not actually killed by these products. Downsides to washing hands using this method include:
- Contact with contaminated taps, towels, or the sink edge after washing hands
- Bacteria stick more readily to wet hands, increasing the risk of contamination.
Healthcare settings traditionally use chemical hand-wash products, such as chlorhexidine in addition to alcohol. These products have antimicrobial/antiseptic properties and are effective against many bacteria, fungi, and viruses.
Most studies comparing the effectiveness of hand rub against regular hand-washing have been performed in healthcare settings. These data show that hand rub is at least as effective as traditional hand-washing with chemical hand-wash products in reducing bacterial counts on skin and in reducing hospital-acquired infections. Furthermore, hand rubs are less irritating to the skin than traditional chemical hand-wash products.
Hand rubs in the COVID-19 era
Hand rubs have been particularly conspicuous during the SARS-CoV-2 pandemic to reduce transmission of the virus via the hands. Pump-packs and sprays of alcohol-based hand rubs are seen in all locations where there may be social contact including shops, restaurants, and doctor's surgeries. Alcohol dissolves the virus envelope and denatures viral proteins. Rubs must contain at least 80% ethanol or 75% isopropyl alcohol to be effective, and 3mL of liquid/foam/gel should be rubbed carefully all over the hands and fingers with a drying time of 45-50 seconds.
Ideally alcohol-based hand rubs should also contain low-allergenic emollients to minimise irritant contact dermatitis. The WHO recommended formulations consist of either 80% ethanol or 75% isopropyl alcohol with glycerol 1.45%, and hydrogen peroxide 0.125% in sterile water. Alcohol-based hand rubs should not include dyes, fragrances, preservatives, or allergenic surfactants due to the risk of allergic contact dermatitis.
Dry hands are common after frequent use of alcohol-based hand rubs, and carrying a small pocket-sized moisturiser in a tube for use during the day may minimise this.
Benzalkonium chloride is less effective against coronaviruses than alcohol in hand rubs.
Side effects of hand rub
It is uncommon to experience side effects from using hand rub. Evidence shows that hand rub is less damaging to the skin than soap and water. However potential skin reactions from hand rubs include:
- Irritant contact dermatitis
- A brief stinging sensation if skin is dry or cracked
- Allergic contact dermatitis, usually to a preservative
- Contact urticaria to the ethanol or other ingredient.
Advantages of hand rub
- Easily accessible – hand rub can be located in areas that are unsuitable for sinks.
- Hand rub is easy to carry when out and about; no drying facility is necessary.
- They are easy and quick to use.
- They cause less dryness and irritation than soap and water.
- They are more effective than regular household soap and water for hands that are not visibly soiled.
- There is less chance of cross-contamination with surrounding objects.
- They are at least as effective as chemical hand-wash products used in healthcare settings.
Disadvantages of hand rub
- Small children should be supervised while using, as ingestion can be harmful.
- Effectiveness is reduced if the product is not used according to directions.
- Hand rub has limited effectiveness against some micro-organisms.
When to use hand rub
- In the home, regular household soap is sufficient to prevent transmission of infectious diseases.
- Hand rub can be used when there is no access to sinks and clean running water.
- Hand rub should not be used when the skin is visibly soiled or contaminated with blood or other body fluids.
- Hand rub is increasingly recommended in healthcare settings.
How to use hand rub
- Hand rub should be applied to dry hands.
- Apply at least 3 mL, or enough to completely wet hands.
- Rub hands together covering all surfaces for at least 10 to 30 seconds until hands are dry.