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The Science Behind Life-Saving Hand-washing: How Soap Kills Viruses & Infectious Micro-organisms 

By Dr. Iorhen Ephraim Akase

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174 years ago in the city of Vienna, a young Hungarian doctor named Ignaz Semmelweis stumbled across a link between pathogens on the hand and the spread of communicable diseases. His solution – a mix of handwashing and instrument sterilization between seeing patients – cut his hospital’s childbed fever rate to below 1 percent and would someday become the basis of a fight against a deadly viral pandemic ravaging the world. 

Beyond the medical profession, this newfound consciousness about the link between hand hygiene and communicable diseases also fueled the development and widespread use of antibacterial and antiseptic products such as Dettol. Hand washing, a relatively low-tech medical solution has saved countless lives over the past two centuries, but now in the era of the SARS COV-2 novel coronavirus (COVID-19), its importance is even more pronounced.

The Science of Handwashing

To understand the true significance of what hand washing does in the context of the ongoing fight against COVID-19, it is important to note that our hands serve as a very effective medium for the transport and transfer of microbes from one person to another. The average human skin/ hand contains about 1500 germs/ each square centimeter of our hands, with the total microbial load in the hands alone estimated to be about 2-10 million in some people! These germs are divided into resident/ non-harmful germs and transient/ harmful germs. 

The resident germs are often difficult to wash off, and help the body with many helpful activities and also help to fight off the harmful germs. On the other hand, the transient (non-resident) germs, which may survive on the hands for between 1-3 hours, can easily be transferred from one person to another through contact. Handwashing with soap movement physically evicts pathogens from the skin surfaces on your hands, which prevents you from transferring them elsewhere. Needless to say, our hands are the parts of our bodies that most come into contact with foreign surfaces and skins. This makes the physical removal of microbes from them particularly important since the COVID-19 virus is said to remain active on surfaces for up to 28 days.

According to Dr. Sallie Permar, an infectious disease researcher at Duke University, soap can also physically disarm the COVID-19 virus by attacking the “envelope” – a layer surrounding the virus that helps them bind on to and invade new cells. Both the virus envelope and the soap molecules have fatty substances that interact with each other and disrupt the envelope, effectively immobilizing the virus and making it unable to infect human cells.

It is important to note that while ethyl alcohol-based hand sanitizers have a similar effect on pathogens like COVID-19, they are not to be considered as a substitute for handwashing. Speaking to the Smithsonian Magazine recently, Chidiebere Akusobi, a Nigerian born infectious disease researcher at Harvard’s School of Public Health explained that while hand sanitizers do kill microbes, they do not physically evict them from skin surfaces, unlike soap which is specifically designed to lift oily dirt off surfaces. In his words:

“Soap emulsifies things like dirt well. When you have a dirty plate, you don’t want to use alcohol—that would help sterilize it, but not clean it.”

The Enhanced Importance of Handwashing in the Coronavirus Era

According to a 2008 American study, the simple act of washing hands after coming into contact with other people and unsterilised surfaces can reduce the risk of contracting a respiratory infection like the coronavirus by up to 21 percent. Statistically, washing our hands with soap and obeying physical distancing guidelines will do more to slow the spread of the virus than any other solution apart from a vaccine.

The COVID-19 pathogen reportedly has the ability to stay alive on surfaces for up to 28 days. This means that objects and surfaces that several people touch regularly such as work surfaces, door handles and hands can become excellent vectors for delivering the virus to new hosts. This is a particularly great risk because patients are known to be infectious even when the disease is still in its pre-symptomatic stage which lasts up to 14 days in most cases.

Washing hands, as seen above will destroy and evict the pathogens from the skin’s surface. More importantly, washing hands regularly will reduce the risk of transmission by getting rid of the virus soon after an individual touches a surface where it is present. Without this measure, the virus would spread very easily, especially among people in close physical contact such as families. It is fair to say that regular hand washing is the single biggest weapon we have against the coronavirus in the absence of a vaccine, which is still at least a year away. 

In the meantime, the simple act of washing hands and implementing social distancing recommendations may be all it takes to keep our families safe from COVID-19.

For accurate and up-to-date advice, please visit or check out You can also call the NCDC Toll free number 08009700010.
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