Keeping hands clean best way to stay healthy

Dear Doctor: Why do you have to wash your hands with soap and warm water for at least 20 seconds? Are they not getting clean if you’ve only got cold water? And why is 20 seconds the magic number? What about hand sanitizers?

Dear Reader: Handwashing is in the news right now due to the coverage of the new coronavirus, COVID-19, as well as our ongoing flu season. It’s an important topic because, although the exact means of transmission of the new coronavirus isn’t clear yet, we do know how influenza spreads, and COVID-19 is likely to be similar.

In addition to inhaling aerosolized droplets from an infected person’s cough or sneeze, influenza spreads through contact with surfaces that have been contaminated by the virus. This can be direct contact, such as when you shake hands with someone infected with the virus, or indirect contact via a contaminated surface or object. If you come into direct contact with the virus and then touch your own mucous membranes, you risk infecting yourself. This includes rubbing your eyes, nose or mouth; biting your nails; eating with your hands; dabbing on makeup; or just resting your chin in your hands. All of this leads to two bits of important advice — don’t touch your face, and do wash your hands. The first relies on awareness, while the latter is all about technique.

Start by wetting your hands with clean, running water. The temperature of the water doesn’t play a role in efficacy; it’s just that warm water is more comfortable to use. If cold water is the only option, that’s fine. What matters most is that you work up a lather with soap — any kind of soap will do — and carefully clean all of the surfaces of your hands. Be sure to wash the palms and backs of the hands, the fingers, the knuckles, the webs between the fingers and the areas around and beneath the nails. Doing this carefully and thoroughly, with gentle pressure to create friction, takes in the neighborhood of 20 seconds. Then rinse well and dry thoroughly. Frequent handwashing can dry out the delicate skin on your hands, so carrying a travel-size moisturizer can be a good idea.

As for hand sanitizers, studies have shown that although they can be helpful, washing with soap and water is the most effective at removing a variety of pathogens. Hand sanitizers may not be as effective when used on hands that are dirty or greasy.

When using a hand sanitizer, it’s important to choose one that is alcoholbased, at a concentration of no less than 60%. The product label will state the concentration of alcohol. Don’t skimp. Always use the amount of sanitizer that the label recommends. Then spread the liquid over all of the surfaces of your hands and rub gently until they are dry.

Hands clean? You’re not quite done yet. There’s another object that makes frequent contact with your hands and face — your phone. Check manufacturer directions, and add cleaning your phone to your daily routine.

What are viruses and how do they work?

Dear Doctor: Everybody is talking about the coronavirus right now, but I still don’t really know what a virus is. How do they work? Why don’t antibiotics kill them?

Dear Reader: You’re far from alone in your struggle to understand viruses. They are simultaneously simple and quite complex, and so small that it wasn’t until the invention of the electron microscope almost 90 years ago that we were even able to see them.

A virus is neither plant nor animal; it isn’t a bacterium, fungus or onecelled organism; and it can’t live or reproduce outside of a living host cell. Considering all that, it’s not surprising that the scientific community continues to debate whether or not viruses are even alive. In fact, it’s almost easier to talk about what a virus isn’t than to explain what it is. But we’ll do our best.

A single virus particle is known as a virion. It’s a packet of genetic material — either DNA or RNA — wrapped in a layer of proteins, known as a capsid. In many kinds of viruses, the protein shell is topped by a layer of lipids, a type of organic compound that’s roughly comparable to fat and is not soluble in water. Taken together, the protein and lipid structure is known as an envelope.

Viruses are mind-bendingly small. They range from about 20 nanometers to upward of 300 nanometers in size, with many tending toward the lower end of the scale. As a point of reference, there are 25.4 million nanometers in one inch. Viruses come in a wide range of shapes, including circular, cylindrical and stringlike. Some, like the coronavirus, are studded with spikes. These act as docking devices to attach to host cells and then use their unique chemical composition to penetrate the cell membranes.

The sole purpose of a virus is to infect another organism — either an animal, plant or bacterium -- make billions of copies of itself and then move on to infect a new host. Small wonder the name for these infectious agents derives from a Latin word that roughly translates to “poisonous slime.”

To achieve its aim, the virion injects its genetic material into the host cell and hijacks that cell’s internal machinery. Instead of doing its designated job, the cell now goes to work replicating the virus. Each virion is so ruthlessly efficient, it can force a cell to make a million copies. The infected cells send out a chemical distress signal in the form of proteins known as cytokines. They set off the inflammatory reaction that causes our immune systems to attack, which results in the symptoms we feel when we’re sick, such as fever, congestion, coughing and sneezing, headache, body aches and gastric distress.

You are correct that antibiotics have no effect on viral illnesses. Antibiotics work by breaching a bacterium’s cell walls, which viruses don’t have, or disrupting its reproduction, which viruses do differently.

Due to antibiotic resistance, which is now a serious problem, it’s important not to use these drugs to fight a viral infection. Instead, for viruses such as the flu, your doctor will prescribe an antiviral, which works by interfering when the virus tries to force the cell to make copies of it.

Eve Glazier, M.D., MBA, is an internist and associate professor of medicine at UCLA Health. Elizabeth Ko, M.D., is an internist and assistant professor of medicine at UCLA Health.