Warding off germs this winter: What's helpful, what's not

If we've learned anything about harmful microbes in the past few years, it's that we need to be proactive about avoiding them. That's especially true during the winter months, when we see an increase in cases of common colds, COVID-19, influenza, respiratory syncytial virus (RSV), and "stomach" bugs (such as norovirus).

How vigilant do you need to be to escape infection from those bugs this winter? It's time to learn what does and doesn't keep you safe, so you can decide which habits to keep and which to let go.

Primary transmission

Harmful microbes spread in several ways.

Respiratory viruses — those that infect the upper respiratory tract (the nose, mouth, throat) or the lower respiratory tract (your windpipe and lungs) — are spread primarily when sick people cough, sneeze, or talk, sending infectious agents into the air. If you inhale them, you can get sick.

It's also possible to contract a respiratory virus by touching recently contaminated surfaces and then touching your eyes, nose, or mouth, although the risk is considered low.

"Stomach" bugs infect the stomach or intestines. These microbes are spread when microscopic particles of feces or vomit from an infected person get into your nose or mouth. This can happen when you have direct contact with infected people, share eating utensils with them, eat food that's prepared or handled by them, eat food or drinks contaminated with infected particles, or touch contaminated surfaces and then touch your mouth or nose.

Strategies that can protect you

Here are the best ways to protect yourself.

Wash your hands regularly. Wash them after shaking someone's hand; as soon as you get home from being out; and throughout the day before touching your face (especially your nose or mouth), preparing or eating food, taking medication, or blowing your nose. Get your hands soapy and scrub for 20 seconds. "Soap causes virus particles to burst open. Gastrointestinal viruses are hardier than other germs, which is why you need to wash your hands a little longer to protect against them," says Dr. Daniel Kuritzkes, chief of the Division of Infectious Diseases at Harvard-affiliated Brigham and Women's Hospital.

Wear a face mask. Face masks, especially those labeled N95 or KN95, help keep viruses from entering your nose or mouth. "Consider wearing a mask in crowded indoor settings, such as a theater, where germs move easily from person to person," Dr. Kuritzkes says. This is particularly true if you have lung or heart disease, and therefore are more vulnerable than most people if you get a respiratory infection.

Get vaccinated. Vaccinations for COVID-19, RSV (for people ages 60 or older), and the flu have been shown to prevent people from getting severe illness. For COVID-19 boosters approved in September 2023: "The data look quite good," Dr. Kuritzkes says. "It's likely that if you got boosted in October, you'll be protected through the winter."

Use caution around sick loved ones. If family members in your home have a respiratory or gastrointestinal bug, Dr. Kuritzkes advises that you avoid close contact, wear a mask when you're near them, and wear rubber or latex gloves to clean up after them. To disinfect surfaces contaminated by respiratory viruses, use commercial disinfectants or a 70% isopropyl alcohol solution. To disinfect surfaces contaminated by gastrointestinal bugs, use products that contain bleach or quaternary ammonium. Don't  use both at once (they produce toxic fumes), and be aware that bleach can damage certain surfaces, such as wood.

What you don't need to do

It's natural to want to do as much as possible to stay healthy. But some practices, such as removing your shoes before entering your home, probably won't keep you safe from winter bugs, although it will help keep your rugs and carpets clean. "Removing your shoes is a custom in many cultures, but there's no infectious disease basis for it. You won't catch anything from walking around your house with shoes on," Dr. Kuritzkes says.

Here are other anti-germ approaches that probably won't make a difference.

Washing your groceries or packages. "It's true that in lab studies a virus can be recovered from surfaces for a few days, but that's done under special circumstances," Dr. Kuritzkes says. "In reality, there's no concern about getting a respiratory virus by touching items at a supermarket or packages delivered to your home. Is it possible that you could contract a gastrointestinal bug if you pick up groceries or packages that were handled by someone who has norovirus? It's possible, but unlikely. Just wash your hands."

Cleaning your smartphone. Dr. Kuritzkes says it would be extraordinarily rare for you to get sick because you touched a contaminated surface and then touched your smartphone, which you put up to your face.

Changing your clothes when you get home. Some people don't want to sit on a bed or sofa in the same clothes they wore outside the house, such as at work or on the bus or subway. But there's no evidence that you'll contract respiratory or gastrointestinal bugs if you do.

Wearing a rubber or latex glove to touch a bank ATM machine or gas pump. Yes, lots of people have touched that ATM or gas pump before you, but all you need to do after touching it is use hand sanitizer, avoid touching your face, and wash your hands with soap and water when you can.

The takeaway

We all have to work hard to stay healthy. That includes maintaining good anti-germ strategies and taking care of ourselves — getting seven to nine hours of sleep each night, eating a healthy diet, limiting alcohol consumption, not smoking, and staying active. The combination of those habits keeps the immune system robust and ready to fight invading microbes.

Should you give up some anti-germ habits if they're probably unnecessary? It's your decision. It won't hurt to follow them, as long as they don't cause you distress.

"Just try to be aware of your actions," Dr. Kuritzkes says, "and don't let your guard down."

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