Elon Answers: Avoiding coronavirus on surfaces

Staff Writer

Editor’s note: The novel coronavirus, known as COVID-19, has created disruptions in daily life for many people. Schools, restaurants and many organizations have closed or changed the way they do business in recent days, leaving community members concerned and unsure of what to expect. This column is part of an ongoing series by Elon University faculty and health care experts from the local community to address common questions and provide scientific information about the pandemic.Most are not trained medical providers, so readers should talk to their doctors if they have questions about their health.

How long does the COVID-19 virus remain active on surfaces? Can it remain on handlebars, doorknobs, and phones for extended periods?

COVID-19 can survive outside of a human anywhere from four hours to three days, but this depends on the surface. Scientists presented an experiment in the New England Journal of Medicine in which virus was sprayed on different surfaces and then looked to see if the virus survived. The virus sprayed into the air can still infect you even after three hours. The virus sprayed on plastic and stainless steel was still present after three days. On copper, the virus lasted about four hours, and on cardboard, the virus lasted less than a day.

If somebody with COVID-19 coughed on a door handle, it is possible another person could get infected by touching the door handle. Fortunately, COVID-19 is weak against common cleaning solutions, like soap and water, hand sanitizer, alcohol and bleach. Keep surfaces clean and keep washing your hands.

I've heard hand sanitizer only kills bacteria, not viruses. Is that true?

The short answer is that both soapy water and hand sanitizer kill COVID-19. The main ingredient in hand sanitizer is alcohol, which can kill COVID-19, many other viruses and most bacteria. These viruses and bacteria have protein walls around them that alcohol breaks down. Some viruses do not have a wall, so hand sanitizers are less effective at killing them. Both the Centers for Disease Control and World Health Organization recommend alcohol-based hand sanitizers as a way to prevent COVID-19.

What about children? I heard kids are less likely to get infected with the COVID-19 virus because they have a stronger immune system. How do adults and children compare?

Children and teens seem to have the lowest risk for COVID-19. The risk gets higher with older age groups. Scientists do not know why this is. Some think that it is because the part of the body targeted by COVID-19 does not work as well in children as it does in adults. Others think that maybe it’s because children tend to get sick with similar infections more often and so their body may be able to mount a stronger defense.

According to the CDC, as of March 18, about one in six people over the age of 85 in the U.S. who got the virus died. About one in 100 people under the age of 55 died. China had a similar pattern, with only one reported death in a person younger than 19. Older people also tend to need more hospital care to recover. About half of the infected people over the age of 85 need hospital care. Only about 1 out of every 100 people under the age of nineteen need hospital care.

Can I catch the virus from someone not yet showing symptoms?

Unfortunately, you can catch the virus from somebody who does not have symptoms. This is one of the big reasons the virus is spreading so quickly. A virus works by taking over specific cells in the body to make more copies of itself. The virus then spreads through the body. It takes time for your immune system to respond by creating a fever. During this time, your body may be producing virus, but you might feel fine. We think this period where you feel fine but can still spread the virus lasts a few days. If you develop symptoms of COVID-19, you should tell everyone with whom you interacted a few days prior to your onset of symptoms. Even after you recover from the virus, Dr. David Ho at Columbia University thinks you might be infectious for a few weeks.

Some scientists think the majority of the cases in China were spread by people who were not showing symptoms, particularly before the Wuhan travel shutdown. This is why it is important to practice social distancing, even if you feel OK.

Jonathan Su is an assistant professor of engineering at Elon University. Reach him at jsu@elon.edu.


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