Experts weigh in on how cautious you should be about bringing germs and other stuff from the outside world into your home.

If the first thing you do when you get home is plop on the couch in the same clothes you’ve been wearing all day, you may want to reconsider.

“As much as I’d like to say, ‘Don’t worry about it,’ the fact is we live in urban societies and in an urban environment. The majority of microbial species — viruses, bacteria, and fungi — are coming from other humans,” Jason Tetro, microbiology researcher, and author of “The Germ Files” told Healthline. “If you’re on the commuter bus, train, subway, at day care, school, or work you can pick up all sorts of bacteria and possibly viruses and fungi from other people and then bring them home.”

Different kinds of microbes will survive in clothing for different amounts of time and it’s difficult to know if people or surfaces you come into contact with are infected with harmful microbes.

So, Tetro says play it safe by changing into a new set of clothes to minimize the chance of transferring microbes to surfaces or other people in the house.

He points out that when people have clothes on, they shed 37 million microorganisms every hour.

“With that in mind, if you’re coming in for 10 minutes and going out again, it’s probably not that big of a deal to stay in the same clothes, but if you’re coming in, sticking around for a few hours, and touching all the different surfaces in your home, it’s a good idea to change,” he said.

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While it’s unlikely to spread serious germs from your clothes into your home, the most concerning germs that can spread and cause infection include:

  • Staphylococcus (staph) is an infection caused by bacteria often found on the skin or in the nose. Tetro says there have been documented outbreaks of staph in homes as a result of someone bringing them inside.
  • Methicillin resistant Staphylococcus aureus (MRSA) is an infection that causes infections in different parts of the body and is resistant to many antibiotics.

“I wouldn’t say you should be overly worried, but we’ve looked at public transportation and have found MRSA, so it’s possible to get your skin affected while taking public transportation, and then potentially bringing it into the home,” Jonathan Sexton, PhD, research specialist in the College of Public Health at the University of Arizona, told Healthline.

Acinetobacter is a bacterium that can cause a respiratory infection that leads to pneumonia. “The likelihood of you becoming infected with this is fairly small,” explained Tetro. “But there have been instances where this can get into something like a pillow. So if you come home after a long day and jump in your bed, and you happen to come into contact with Acinetobacter, you could transfer that to your pillow and then that may end up leaving you with the possibility of inhaling it and then getting sick.”

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Since your shoes usually don’t touch surfaces that you sit or lay on, Sexton says taking them off in the home isn’t crucial.

However, he notes that one study he worked on found fecal coliforms, indicators that there are feces on shoes, and E. coli and other bacteria can be in that feces.

“That’s what you worry about. But unless you visibly step in something nasty, most people probably don’t think about how they may have feces on their shoes,” Sexton said. “If you have hardwood or tile floors I’m not as worried about shoes in the house since those surfaces are easier to clean and disinfect vs. carpet, which you can’t really disinfect every day.”

However, if you have children who crawl or play on the floor or if you are on the floor, Sexton says consider taking off your shoes.

A big picture way to look at this is to consider whether or not you or anyone in your home has a suppressed immune system, which increases the chances of infection, adds Tetro.

“About 30 percent of the population has some form of suppressed immune system whether that’s related to age or medications,” he said. “When you’re thinking about coming into the home, think about how healthy everyone in your house is and how their immune systems are. That will help you decide how cautious you are with changing your clothes and taking off your shoes.”

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Our bodies have more germs than our own human cells, says Sexton.

“Pretty much every inch of our body is covered in germs. We could not live without germs. They help us digest food and give us amino acids we need to survive. They help prevent the bad germs from getting a foothold [on our immune systems] and causing an illness,” he explained.

When germs become a problem is when they carry a pathogen that could cause an illness. Because of this, Sexton doesn’t believe we are too clean.

“I love disinfectants. Even after you clean a surface it will be re-contaminated with natural germs pretty rapidly,” he says. “I’m for cleaning because there are some germs and illnesses you can get over and over again.”

For instance, if you have Norovirus, you can get it again as soon as you’re better.

“I like to clean to avoid viruses that you don’t build an immunity to. I’m not worried about if the grocery store or park isn’t clean, but I do like my house to be clean because that’s where I spend the most time and that’s where I can be re-infected,” said Sexton.

Tetro suggests focusing on targeted hygiene as opposed to keeping your entire home super clean.

“In essence, if you are cleaning on a regular basis because you are concerned about microbes in the kitchen or bathroom, that’s a good thing. But if you are bleaching the whole house often, it’s not going to be helpful because there are quite a number of microbial species that are beneficial for you and the environment since they kill pathogens,” he said.

Think of it this way: You don’t want your home to be sterile, but you want to make sure you clean areas that present risk.

“When you bring something in from the outside, whether it be shoes or clothes, think about what they will come in contact with,” said Tetro.

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Your best defense against germs is to wash your hands with soap (it doesn’t have to be antibacterial) and water.

Sexton says wash for 30 seconds in between your fingers and under your fingernails.

“We do studies [on kids and adults] and ask them to put on a glow germ lotion, which shows the germs on their hands under a black light. Then we ask them to wash their hands. The fingernails are always where they miss the most, even in adults too,” Sexton says.

Tetro agrees, noting that people touch their faces, noses, mouths, and eyes, on average anywhere from five to 16 times per hour.

“If you have microbes of the flu, staph, or respiratory virus on your hands and then you touch your face, you can infect yourself,” he says. “Make it a routine to come home, change your clothes, and wash your hands, and you’ll be good.”