How Long Does Flu Live on Surfaces

Here’s how to protect yourself from surface transmission this season.

‘Tis the season for cooler temps, shorter days and cozy nights by the fire. Unfortunately, this time of year also marks the start of flu season, which typically lasts from October through May.

The flu spreads primarily through respiratory droplets that get airborne when an infected person coughs, sneezes or even talks. But the flu doesn’t just leap from person to person through the air. Those tiny droplets can land on surfaces, and you can catch the flu by touching objects contaminated with the influenza virus and then touching your mouth, nose or eyes.

“These surfaces like countertops, doorknobs or your keyboard can harbor the influenza virus for up to 48 hours, depending on the environment, and pass them on to others,” says Stanley Martin, MD, an infectious diseases physician at Geisinger. “You can’t avoid every place germs are hiding, but you can take precautions to better protect yourself from surface transmission this season.”

How long does flu live on surfaces?

Flu viruses can remain infectious on surfaces for varying lengths of time, influenced by several factors.

“Fortunately, the influenza virus cannot bear the harsh environmental conditions outside the human body and diminishes in strength rapidly,” says Dr. Martin. “So, the longer the virus sits on a surface, the lower your risk of catching the flu just by touching it.”

Temperature

Low temperatures can prolong the survival of the flu virus, while high temperatures tend to shorten its lifespan. Inside the body, warm temperatures melt the protective outer covering of the virus, so it can infect other cells. However, when warm temperatures melt it outside the body, the virus is vulnerable to the elements and weakens.

Humidity

In dry, low humidity air, the flu virus can become airborne and more easily spread through respiratory droplets. In high humidity, however, there are more water molecules in the air that interfere with transmission.

Type of surface

Influenza viruses tend to survive longer on hard, nonporous surfaces than porous surfaces. Research shows both influenza A and B viruses survive for 24 to 48 hours on hard surfaces like stainless steel, doorknobs and plastic, but survive for less than 12 hours on cloth, paper and tissues.

“Once transferred to hands, the virus’ lifespan drops significantly and is only infectious for about 5 minutes,” says Dr. Martin. “But, if you consider how many times you itch your nose, rub your eyes or shake hands, even that is plenty of time to spread the virus.”

Common surfaces where flu germs can be found

Shared items or surfaces in high-traffic or high-touch areas are a favorite of germs. Unfortunately, some may be less obvious and don’t get cleaned as often as they should to keep flu germs at bay, such as:

Cell phones and tablets
Computer keyboards and mice
TV remotes
Countertops
Light switches
Appliance handles and doorknobs
Toys
Paper money
Shopping carts
Point-of-sale keypads in stores or restaurants
Subway poles

“People are typically cautious about germs in public spaces, but we also need to be cautious about germs inside our homes,” says Dr. Martin. “Germs we come into contact with in public spaces can hitch a ride back home with us.”

Preventing the spread of flu

When it comes to flu prevention, it’s important to focus not only on person-to-person transmission, but also on surface transmission.

Dr. Martin recommends these measures to protect yourself from a bout with the flu this season:

Practice good hand hygiene. Wash your hands frequently with soap and warm water for at least 20 seconds. If a sink isn’t available, use an alcohol-based hand sanitizer.
Cover coughs and sneezes. Use a tissue or the inside of your elbow when you cough and sneeze. Be sure to throw the tissue away immediately.
Avoid touching your face. Your mouth, nose and eyes are entry points for the flu virus. You can infect yourself with the flu if your hands are contaminated and you touch your face.
Regularly disinfect commonly touched surfaces. Be sure to follow product instructions for effective use. For example, some require a surface to stay wet for at least 30 seconds to sanitize. Also, wash linens and towels in hot water and tumble dry in high heat to help kill germs.
Use a humidifier. Running an in-home or portable humidifier adds moisture back into the air and can restrict transmission of the flu virus.
Get the flu vaccine. Your best defense against the flu is getting vaccinated every year.

“The flu vaccine helps protect against the most common strains of the flu virus and reduces the severity of symptoms if you do get infected,” Dr. Martin says. “Most people should get the flu vaccine annually, as the virus can mutate and new strains can emerge each year.”