Keeping COVID-19 at Bay
The current health advice for washing hands with soap and water is based on the ability of soap molecules to interfere by breaking down the outer fat (lipid) layer of viruses.
The anatomy of a virus
Viruses, including coronavirus, consist of three main building blocks; ribonucleic acid (RNA); the viral genetic material similar to DNA, proteins; and lipids - the outer coating of the virus that protects the genetic material and aids with viral spread and cellular invasion. These three components spontaneously self-assemble to form a compete virus, with weak, 'non-covalent' bonds between the proteins, RNA and lipids.
Viruses work by invading a cell and using the cellular machinery to force the cell to replicate the viral RNA and viral proteins, which then rebuild into new viruses. This accumulation of viruses eventually causes the cell to die or burst, releasing the viruses to then infect more cells.
To the rescue: soap based products
Soap molecules compete with non-covalent bonds between proteins, RNA and lipids to effectively dissolve the glue that holds viruses together. Soap can also disrupt the interactions between the virus and the skin surface, removing viruses from the skin. This is all due to the 'amphiphilic' nature of each soap molecule which features a hydrophilic (water-loving) head and hydrophobic (water-hating) tail.
Viruses are surrounded by a lipid bilayer made up of two bands of hydrophobic tails sandwiched between two rings of hydrophilic heads. When exposed to soap and water, viruses are prised apart, as the hydrophobic tails of the soap molecules attempt to escape
from water and wedge themselves into the lipid envelopes of the virus, rupturing the viral membrane.
Non soap-based cleaning products
Despite not being developed specifically as virucidals, many cleaning products possess the same amphiphilic ability as soap, and therefore dissolve the fat membrane that surrounds a virus, rendering it inactive on freshly cleaned surfaces.
Disinfectants are also useful in the fight against COVID-19, and should be used for spot treating door handles and other high-touch surfaces.
Alcohol-based Hand Sanitizers
As solvents, ethanol and other types of alcohol are more lipophilic (fat-loving) than water. This means that alcohol does dissolve the lipid membrane and disrupt the virus. However, a high concentration of alcohol (≥60 per cent) is required.
Hand sanitizers are especially useful when soap and water are not available.
Regardless of the products you use, it is important to ensure surfaces are cleaned thoroughly on a regular basis, as early reports suggest COVID-19 may stay active on surfaces for many hours depending on ambient conditions (including moisture, sunlight and heat).
Surfaces are also easily contaminated if touched by someone who is harbouring the virus on their hands.
Combining soap or detergent products with disinfectants or sanitizers also represents a new 'gold standard' in protection against COVID-19, as the virus detaches from the skin or a hard surface only then to fall apart in hot, soapy water.