Cold and flu were getting bad here a couple of weeks ago. I had not been sick for near a year but decided I would start regularly using hand sanitizer because of the amount of sick people, elevator buttons to push and door handles in the office. I used the sanitizer religiously and washed regularly with hot soapy water. My hands were turning white and wrinkling from the abuse. I was sick with the most nasty head cold within a week. It still makes people nauseous to hear me cough.
I have to wonder if killing every living bacteria and virus on my hands caused me to get sick. Seems so random.
Doubtful. Colds and influenza viruses are passed from one person to the next by the droplets made when people with flu cough, sneeze or even talk or breathe. These droplets can land in the mouths or noses of people who are nearby or possibly be inhaled into the lungs. Less often, a person might also get flu by touching a surface or object that has flu virus on it and then touching their own mouth or nose.
Hand sanitizer and frequent hand washing can help with the former but not the latter method of transmission.
It’s probably better to use it when there is sickness going around but not all the time, like when there is no sickness. Flu and cold season is when you should use it. Keep in mind that germs are also airborne. If somebody sick coughs or sneezes close enough to you, you can still get it. That’s why I don’t go shopping when it’s crowded during flu season. If I do get in that situation I carry some of the thin surgical masks. They look kind of stupid but it’s better than getting sick.
I never use the sanitizer any time other than flu season or when there is some other really bad illness going around. Your immune system needs something to do to keep it working but using it when needed won’t hurt anything.
I’m cautious during flu season because I’m 63 and I have asthma. Pneumonia is a very dangerous thing for me. I’m healthy but pneumonia is a killer with people with asthma or other respiratory issues.
For bacteria, I suspect over-use can cause you to get sick. You are covered inside and out by a variety of organisms that serve as your first line of defense against many more invasive ones (primarily by out-competing them).