I am not one of the neurotic people who carries a little bottle of hand sanitizer around with me on a regular basis. However, until this flu bug passes I WILL BE FROM NOW ON.
I found it rather curious, being a scientist (analytical chemist, not a biologist) and all, that the CDC web page was advising people in addition to washing their hands on a regular basis, to use 'alcohol hand lotions' (i.e., hand sanitizers) when soap was not available and your hands are not visibly dirty.
Now, I recall numerous people saying that alcohol won't kill viruses...so I did a little digging...what I found over the bump.
So, I have to travel to Denver to get my kids next week so that they can be at my graduation...and especially since a Denver airport worker was officially diagnosed with H1N1, I decided to do as much research as possible to see how I could minimize exposure risks.
At the CDC domestic travel advisory site, they give this info
Practice healthy habits to help stop the spread of influenza
- Wash your hands often with soap and water. This removes germs from your skin and helps prevent diseases from spreading. Use waterless alcohol-based hand gels (containing at least 60% alcohol) when soap is not available and hands are not visibly dirty.
- Cover your mouth and nose with a tissue when you cough or sneeze and put your used tissue in a wastebasket.
- If you don't have a tissue, cough or sneeze into your upper sleeve, not your hands.
- Wash your hands after coughing or sneezing, using soap and water or an alcohol-based hand gel.
- Follow all local health recommendations. For example, you may be asked to put on a surgical mask to protect others.
So why is the CDC advising the use of alcohol based hand sanitizers if they don't kill viruses? Well, the short answer to that question is that it does kill some viruses...but not all. So some further digging found this piece, while not a scientific journal article, it makes sense.
It is true that some viruses are readily inactivated by alcohol; however, some are not. Viruses consist of nucleic acid (either RNA or DNA) surrounded by a capsid (protein shell). Some viruses have an additional external layer or wrapping known as an envelope. The envelope is created from a piece of phospholipid membrane that comes from the infected host cell during the "budding" process when viral particles leave the infected cell. Enveloped viruses are referred to as lipophilic viruses, because of their lipid envelope, while nonenveloped viruses are referred to as non-lipophilic viruses.
Generally, enveloped (lipophilic) viruses are susceptible to alcohol: Herpes simplex virus (HSV), human immunodeficiency virus (HIV), influenza virus (Flu), respiratory syncytial virus (RSV), vaccinia virus, Hepatitis B and C viruses are considered susceptible to alcohols. However, certain nonenveloped (nonlipophilic) viruses such as hepatitis A and enteroviruses, which are both responsible for viral gastrointestinal infections. Depending on the alcohol concentration of the hand-cleanser and time of exposure to the alcohol, hepatitis A and other nonlipophilic viruses may not be eliminated.
So it is believed that flu viruses, since they are coated in a lipid bilayer (same as a cell membrane), are susceptible to alcohol!
This is no excuse not to wash hands regularly...(at least 20 seconds of vigorous scrubbing with warm-hot water...lets see those bubbles kiddies!), but as an added precaution it is also a good idea especially in places where there are people but no available restrooms. Personally, in public restrooms, I make a habit of taking a clean paper towel with me to open the door when I am leaving...because you never know what is on that doorknob/handle.
and one last tip about the use of hand sanitizer from the above cited web page...
The effectiveness of alcohol in ridding hands of potentially infectious microorganisms is dependant not only on the alcohol concentration, but the time of exposure, and the volume of alcohol as well. It is important to ensure adequate contact between the cleanser and the then hands. Although the optimal volume of alcohol-based cleanser has not been determined, it is suggested that if hands feel dry after rubbing hands together for 10-15 seconds, an insufficient volume was likely applied.
For those of you with a scientific curiosity...there is a very interesting exclusive interview (from 4/29/09) at Science Magazine's Blog of the CDC's chief virologist about the H1N1 virus...and explains that it is essentially a swine-only virus, and that any human and/or avian components were actually acquired by the strain at least 10 years ago....
One thing particularly troubling from the interview concerns the ability to produce vaccines for this strain...
Q: Is there anything I didn’t ask you that I should have?
R.D.: We all pray this remains sensitive to antivirals. We all hope that vaccines will be developed. The virus doesn’t grow very well in eggs. We hope the virus will improve [the] ability to grow in eggs so we can produce [a] vaccine very quickly so these secondary and tertiary cases can be controlled. In some countries there’s good surveillance, but in others, who knows.
This is all the reason I need to start writing to congress to as for increases in vaccine research. We need the next generation of vaccine production facilities that don't require eggs...and we need them yesterday!