Winter is marked by an increase in people getting sick, so handwashing becomes even more essential at this time of year.

Certain conditions common to winter can make it easier for infectious agents to spread. Northwestern Medicine says the body is not as effective at fighting a virus when cold air enters the nose and upper airways. That means the flu, the common cold, and even COVID-19 can spread more easily in the winter. Also, people tend to huddle indoors where it is warm when the mercury outside drops. That puts people in closer contact with others who may be harboring these viruses or other infectious diseases in their bodies. Individuals often get less exposure to sunlight during the winter, which can adversely affect their natural production of vitamin D. Low levels of vitamin D have been linked to a weakened immune system, which can make fighting illnesses more difficult.

The Centers for Disease Control and Prevention (CDC) says handwashing is an important step in staying healthy all year long, and especially during the winter. Many diseases and conditions are spread by not washing hands with soap and clean running water. The CDC says that, in addition to the aforementioned viruses, people can become ill from exposure to even small amounts of feces from people or animals, as feces can contain salmonella, E. coli, and norovirus. It also may spread some respiratory infections like adenovirus and hand-foot-mouth disease. These germs can get onto hands after people use the toilet or change a diaper, but also after handling raw meats that have minute amounts of animal feces on them. 

Germs from unwashed hands can be transferred to objects like tabletops, door handles, and even foods and beverages.

People should wash their hands frequently, and especially after using the toilet; changing diapers; before, during, and after preparing food; before eating; before touching their nose, eyes or mouth, including handling dentures or orthodontic aligners; after sneezing, coughing or blowing their nose; and when they arrive home from shopping or being in high-traffic public areas.

To do this task properly, a person should wet his or her hands with clean, running water and use soap if it is available. Any soap will do. Antibacterial products are not essential.

Nemours KidsHealth says people should lather up for about 20 seconds and make sure to get in between the fingers, on the back of the hands, and under the nails where germs like to linger. The wrists should also be washed.

If possible, people should remove rings and watches before washing their hands, or try to at least move the rings to wash under them.

Hands should be rinsed well under running water to remove all traces of soap, and then they may be dried by using a clean towel or by air drying. It is best to use paper towels or a single-use cloth towel.

In public restrooms, people are advised to use a clean paper towel to turn off the faucet and open the door. At home, they should routinely wipe down faucets and handles with cleansing products to remove germs from these high-touch points. Frequent laundering of towels also can be effective.