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Hi. In the answer to a question about ethyl alcohol and bacteria you-all wrote that ethyl alcohol can kill bacteria because it denatures the proteins in the cell and dissolves the cell membrane. I am trying to figure out how the ethyl alcohol in handgel affects viruses. I have read that all viruses have a protein coat that protects their genetic material and some have an envelope of fat that surrounds them. If the virus coat/shell is made up of proteins and /or fat if ethyl alcohol denatures the proteins in a bacterium cell, does it also denature the proteins and/or fat that make up the virus coat? If it does this, is this the reason we could say that hand gel is effective in killing viruses that may get on your hand?
Question Date: 2010-01-25
Answer 1:

Hand gel isn't likely to kill viruses. First it's useful to note that viruses aren't really 'alive' in the sense that they grow and reproduce in the context we're used to thinking of. They need a host to insert their DNA into in order to reproduce and can essentially wait forever, without food or water, until the opportunity to infect a host presents itself. Instead of investing their resources in traditional modes of life, they invest their resources in extra strong proteins to protect them. Think of wearing a thick down coat vs. a windbreaker in freezing weather; they're both coats, but they have different jobs, the down coat was likely more expensive and keeps you warmer, but if you don't live in the cold then you don't really need to buy one. Ethanol may be able to do some damage to the protein coat of a virus, but will not penetrate, thus 'kill' a virus. Other solutions can kill viruses (e.g. straight bleach) but they would also likely do damage to your skin if used regularly, so not a good candidate for a hand gel type application.


Answer 2:

Your reasoning is correct!Many viruses are surrounded by a shell formed of proteins and fat (lipids). Ethanol (ethyl alcohol) also denatures the coat of the virus, rendering it inactive. Great thinking!

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