Will I get sick from opening a package? What about handling a library book? Is it safe to drink from a water fountain? What about lifting weights at the gym? Do I need to worry about my toddler’s habit of putting everything in his mouth? We know that the coronavirus can survive for a little while on surfaces, which leaves a lot of questions about the specifics.
To answer some of your questions, we turned to two infectious disease specialists at the McGovern Medical School at UTHealth: Susan Wootton and Michael Chang. Both are MDs with extensive experience in treating infectious disease, and were willing to answer all our questions and concerns about how long the COVID-19 virus can survive on different surfaces and the best ways for protecting ourselves.
What do we know about the virus’s survival on different surfaces?
Studies on how long the coronavirus survives on different surfaces are still on-going, which leaves a lot of open questions. The good news is that, according to the World Health Organisation, COVID-19 appears to act a lot like other coronaviruses, which helps give us an idea of what to expect.
So what do we already know?
We know that how long coronaviruses last on different surfaces ranges between several hours to several days, depending on factors such as temperature and humidity. Meanwhile, a study showing coronaviruses can last for up to 9 days was performed in a controlled laboratory condition.
According to Wootton, in the real world, the length of survival will vary, with the most likely estimate being a couple hours, based on factors such as temperature and humidity.
“The virus will last longer in wet, cool environments,” Wootton said. Generally speaking, hot and dry conditions are bad for the virus and good for us.
Some other good news? A recent review of a whole bunch of studies on different coronaviruses show that disinfecting surfaces works really, really well for killing off the virus.
What objects do I need to be careful with?
Library books are generally ok, Wootton said, while you should be careful with surfaces that are handled by a lot of different people. “High-touch, high-contact surfaces are the ones to focus on,” Chang said.
Water fountains, gym equipment, shopping carts, door handles, and daycare toys all have the potential to be harbouring a lot of bugs, while items such as books and comforters, which aren’t usually shared that much, don’t pose as much of a risk. So it’s best to keep your toddler from putting all of the toys in his mouth and to exercise caution when touching items that a lot of other people have touched. If you have to touch something that might not be clean, your best bet is to wash your own hands after, and avoid touching your face.
Meanwhile, the World Health Organisation says that there is a very low risk of spread due to packages shipped over a period of days or weeks.
One item people definitely need to clean: Your phone. We carry our phones with us everywhere, handle it more times a day than we can count, which makes it the ultimate repository for all of the nasty bugs we encounter during the course of the day.
If you have access to one, there are UV disinfection boxes that can do the trick. If not, a lint-free cloth lightly dampened with a 1:1 combination of 70% isopropyl alcohol and diluted water will work.
How should I clean in order to avoid getting sick?
“I wouldn’t worry as much about soft surfaces,” Wootton said. “Focus more on high-contact hard surfaces such as door handles and kitchen counters.”
For places like the gym, it’s important to wipe down your equipment after use. The commercially available disinfecting wipes found at most gyms do actually work, Chang said, as long as they have some combination of isopropyl (rubbing) alcohol and/or benzyl ammonium chloride. The rubbing alcohol acts as to kill the germs, while the benzyl ammonium chloride removes dirt and pathogens.
The important thing is to let the surface air dry after wiping it down with a disinfectant. Don’t immediately follow that disinfectant with a towel, as that limits the amount of time the alcohol has to kill the virus.
For more specifics, the U.S. CDC has issued some guidelines for cleaning and disinfecting a household. Cleaning is the removal of germs and dirt from surfaces. Although this doesn’t kill germs, removal lowers the risks of spreading infection. Disinfecting is using chemicals to kill germs on surfaces.
For cleaning and disinfecting, the CDC recommends wearing gloves to clean dirty surfaces with detergent, then disinfecting with either a diluted bleach solution or an alcohol solution that is at least 70% alcohol. Just make sure, when you are using these products, to do so in a well-ventilated area.
For laundry, the recommendations are to wash as usual, with the warmest water possible, and then dry to completion. Remember: viruses don’t do well in hot and dry conditions. If you want to zap those viruses, the dryer is the perfect place.
How often should we clean?
“At a minimum, once daily, focusing on those high-contact surfaces,” Chang said.
So indulge your inner neat person, start scrubbing, and don’t forget to wash your hands.