Following my June 10 article in The Korea Times, I was very privileged to receive emails from readers asking more questions about MERS. Two questions in particular stood out.
The first involves hand sanitizers. A number of readers wanted to know how effective they are against viruses. A friend of mine who works for Kimberly-Clark (the parent company of Kleenex tissues) has informed me reliably South Korea is experiencing a huge spike in hand sanitizer sales. So the question is: do these products really protect you against MERS?
Before answering the question, we must first recognize there are two main categories of sanitizers: those containing germicides and those containing alcohol. Germicides function by interfering with metabolic processes and are particularly effective against bacteria and fungi but to a lesser degree against viruses.
In Korea, virtually all hand sanitizers marketed for public consumption contain alcohol (ethanol or isopropanol). Alcohols disinfect by disrupting cell membranes, which are made up of lipids (oil). For those of you who have used cotton drenched in alcohol to clean grease or oil know what I’m talking about. The simplicity of this oil-disruption mechanism is extraordinarily effective against bacteria (and to a lesser degree, fungus) because the alcohol simply obliterates the membrane housing the contents of the cell.
So what about viruses? It turns out some viruses have lipid membranes while others do not. Not surprisingly, alcohols are much more effective against the viruses with membranes. Luckily for us, coronaviruses such as MERS and most cold viruses have these membranes, making alcohol sanitizers very effective against them.
Recent work from Dr. Mark Sobsey’s lab at the Center for Disease Control (CDC) in Atlanta has shown that a 1-minute exposure of coronavirus to sanitizers containing 60 percent or more alcohol can result in a reduction of the virus by over 99 percent. And although this exposure time is appreciably longer than the average exposure of rubbing sanitizer on your skin, it is still compelling evidence that alcohol should be effective.