[Reading Science] Should Wounds Be Disinfected with Strong Alcohol?

In movies, when characters get injured, they disinfect the wound with alcohol and sometimes even drink it. Does alcohol really have disinfectant effects?
[Photo by movie 'John Wick' screenshot]

[Asia Economy Reporter Kim Jong-hwa] The COVID-19 pandemic has led to many situations that are hard to laugh about. Under normal circumstances, these might be funny, but given the times, one representative example of such a situation is 'disinfecting with alcohol.'

Disinfecting with alcohol is not unfamiliar since we have seen it often in movies. Scenes where a character with a gunshot wound pours alcohol on the injured area to disinfect it have become one of the most common scenes in films. But does disinfecting with alcohol actually work in real life?

Japan is the country that officially recognized disinfecting with alcohol, leaving the world neither laughing nor crying. On the 13th, as COVID-19 cases surged and the medical community complained about a shortage of disinfectant alcohol, Japan’s Ministry of Health, Labour and Welfare granted a special exception allowing the use of high-alcohol-content liquor for disinfection purposes.

There is a similar case. To prevent the spread of COVID-19, large entertainment venues and clubs voluntarily closed, but young people, having nowhere to go, ignored social distancing and gathered at street food stalls for what is called 'hunting' as a way to relieve stress.

The problem is their lack of safety awareness. Some young people do not wear masks and confidently say, "We are young and have strong immunity, so we won’t get infected," and "The virus can be disinfected with alcohol." This is not unique to Korean youth. Young people in severely affected countries like Europe and the United States also visit bars and clubs in the evening, confidently believing that "disinfecting with alcohol works."

As the situation escalated, the World Health Organization (WHO) recognized the seriousness and took action. On the 14th (local time), the WHO Europe office posted on its website that "dangerous and false information is circulating that drinking high-alcohol-content liquor can kill the virus," and clarified that "this is absolutely not true."

The idea that hospitals are disinfecting with liquor like in movies due to a shortage of disinfectant alcohol, and that people think they can disinfect the virus inside their bodies with alcohol, is ridiculous. However, the fact that disinfectant alcohol is depleted in hospitals shows how severe the situation is, and young people’s failure to grasp the seriousness is no laughing matter.

Does alcohol actually have a disinfecting effect? While alcohol used as a disinfectant is indeed included in liquor, the alcohol concentration is too low for it to be effective as a disinfectant. High-alcohol-content liquor might have some effect, but it is not recommended due to the risk of secondary bacterial infection.

Japan’s Ministry of Health, Labour and Welfare, which allowed the use of liquor for disinfection, stated that "liquor with an alcohol concentration between 70% and 83% can be used as a substitute for disinfectant." This means that liquor with too low or too high alcohol content is not suitable. Why is that?

Pure 100% alcohol actually has no disinfecting effect. Alcohol disinfectants used in hospitals are diluted liquids with a concentration of 70-75%, with the remaining 25-30% being water. The reason why 100% alcohol cannot kill bacteria but 70% can is due to the sterilizing mechanism of alcohol.

Soju, which is popular among Koreans, does it disinfect? While washing hands as shown in the photo might be useful, it has no effect on disinfecting wounds at all.
[Photo by YouTube 'Hogisul Cheonguk' screenshot]

The alcohol used for disinfection is ethanol (ethyl alcohol C5H5OH), which has strong osmotic ability and can penetrate the bacterial membrane well. Ethanol penetrates the bacterial membrane and coagulates the bacterial proteins, killing the bacteria.

However, 100% ethanol coagulates proteins too quickly, causing the bacterial surface proteins to coagulate all at once. This creates a hard layer on the bacterial surface that ethanol cannot penetrate, preventing it from reaching the proteins inside the bacteria. Therefore, to achieve effective sterilization, water is mixed with 100% ethanol to reduce the concentration to 70-75%.

Soju, a popular Korean liquor, has no effect on disinfecting wounds. However, it might help in washing hands to remove bacteria, as soju could act somewhat like soap. But would anyone really buy expensive soju just to wash their hands? That is truly laughable.

If you want to disinfect a gunshot wound like in the movies, you would need something like vodka. If you must disinfect a wound with liquor due to unavoidable circumstances, the alcohol concentration should be over 70%. Saying "the virus can be disinfected with alcohol" while drinking soju is just wishful thinking. The claim that drinking alcohol disinfects the virus is something that would make even cows laugh.