Although the Centers for Disease Control and Prevention (CDC) recommend washing the hands with soap and water, this mode of cleansing is not always available. When it is not, using alcohol-based hand sanitizers can help prevent transmission of viral infections, SARS-CoV-2, the virus that causes COVID-19.
As well as using sanitizers to cleanse the hands, people can use rubbing alcohol to disinfect frequently touched objects in the home, such as phones and computer keyboards.
This article discusses how well alcohol can kill viruses, how it works, and what concentrations to look for. It also provides instructions on how to use hand sanitizers and rubbing alcohol.
Does Alcohol Kill Viruses?
Isopropyl alcohol and ethyl alcohol can kill an array of viruses. Isopropyl alcohol is the main ingredient in rubbing alcohol, while ethyl alcohol is the type of alcohol present in alcoholic beverages.
The efficacy of these alcohols depends on their concentration and the type of virus. Enveloped viruses have a lipid membrane, while none developed viruses are those without a lipid membrane. Generally, none developed viruses are more resistant to disinfectants.
Isopropyl alcohol works against enveloped viruses, but not against none developed viruses. Ethyl alcohol works against enveloped viruses and a few none developed viruses. Both ethyl and isopropyl alcohol have potent antiviral action against:
• herpes virus
• HIV
• hepatitis B
• SARS- COV-1
These alcohols do not have antiviral action against none developed viruses, such as
Polio and hepatitis A.
How does it work?
Few studies have looked at how alcohol kills viruses. However, scientists believe alcohol disrupts the cell membrane of the virus by changing the structure of its proteins. A 2021 article refers to this process as “denaturing and coagulation.” Without a functional membrane, the virus cannot reproduce and cause infection.
Adding water to alcohol makes it more effective in denaturing the proteins. This is because alcohol on its own evaporates very quickly. Water slows this down, exposing viruses to the alcohol for longer.
Can alcohol kill SARS-CoV-2?
SARS-CoV-2 is the virus responsible for the COVID-19 pandemic. Since the outermost membrane of SARS-CoV-2 contains lipids, alcohol is effective against it.
A 2020 study found that certain concentrations of ethyl or isopropyl alcohol rendered the virus inactivate after 30 seconds. The CDC advises using alcohol-based hand sanitizers to prevent SARS-CoV-2 transmission when soap and water are not available.
How strong does the alcohol need to be?
A 2021 research article states that the recommended concentration of alcohol in sanitizers is 80% ethyl alcohol or 75% isopropyl alcohol. However, sanitizers containing at least 60% alcohol are also effective, according to the CDC.
The 2020 study that evaluated the impact of hand sanitizer formulations on SARS-CoV-2 found that concentrations higher than or equal to 30% resulted in complete viral inactivation.
How to use alcohol in the home
People can use alcohol-based sanitizers or rubbing alcohol around the home to clean small objects and high touch surfaces, such as phones or door handles. To clean these items, first:
•Ensure the room has good ventilation.
•Apply rubbing alcohol to a cotton pad.
•Replace the cap to avoid inhalation.
•Wipe the pad over the surface.
•Dispose of the cotton pad safely.
How to use alcohol on the skin?
There are two ways to use alcohol on the skin to kill viruses. The first is using alcohol-based hand sanitizer gel. People can use this by applying some gel to the palms and rubbing all over the hands, including between the fingers. Then, wait until it dries.
Doctors no longer recommend that people use rubbing alcohol to clean wounds, as it can further damage tissue. Instead, a person can rinse the wound under running tap water for 5–10 minutes before soaking a gauze pad in saline solution or tap water and gently dabbing or wiping the skin with it. Alternatively, they can use an alcohol-free wipe.
Are there downsides to using alcohol to kill viruses?
While alcohol gels and sterilizing products effectively kill a number of potentially harmful microbes, they have some disadvantages.
Inferior to washing with soap and water
The CDC advocates washing hands with soap and water whenever possible. Unlike hand sanitizers, soap and water can remove all kinds of germs from the hands. This includes all types of bacteria, viruses, and other substances, such as pesticides.
In some situations, washing the hands with soap and water is necessary for proper hygiene. These include:
• Before, during, and after food preparation
• After using the toilet
• After touching garbage
• When the hands are visibly greasy or dirty
• Before and after caring for a person who is sick
• Before and after visiting someone with a weakened immune system
If soap and water are not available, use a sanitizer that contains at least 60% alcohol.
Inferior to other surface cleaners
Alcohol is less effective than some other disinfectants for cleaning surfaces or equipment. For example, in hospitals, staff typically opt for hydrogen peroxide or other disinfectants instead of alcohol to clean surroundings, such as floors.
These substances can kill a wider variety of microbes than alcohol and do not evaporate as quickly, meaning they are in contact with the microbes for longer. However, they have their own pros and cons and have not entirely replaced alcohol.
The fast evaporation of alcohol can be an asset when disinfecting noninvasive equipment, such as thermometers. Additionally, unlike hydrogen peroxide, alcohol does not discolor clothes and fabrics.
Antibiotic resistance
Alcohol-based sanitizers have antibacterial properties in addition to their antiviral ones. However, bacteria can evolve over time so that substances no longer harm them. This is known as antibiotic resistance.
Some researchers have concerns that hand sanitizers may contribute to antibiotic resistance. However, a 2021 research article report that alcohol has not shown the potential to cause bacterial resistance.
Certain experts advise cleaning the hands with sanitizer for a full 20–30 seconds and allowing it to dry to reduce the chance of leftover bacteria evolving resistance.
Summary
Both isopropyl and ethyl alcohol can kill viruses that have cell membranes with high lipid content. SARS-CoV-2 fits into this category, along with HIV, the hepatitis B virus, and herpes viruses. Alcohol works by changing the structure of the viral membrane, making it unable to function.
Washing the hands with soap and water is superior to using alcohol-based sanitizers. However, when this option is not available, people can use hand gels containing 60 - 90% alcohol. The optimal concentrations are 80% ethanol or 75% isopropyl alcohol.
People can also use rubbing alcohol to clean small items around the home, but it is important to follow precautions while handling it.
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