The answer is probably not what you want to hear. How long do microbes like bacteria and viruses live on surfaces in the home at normal room temperatures? Art Dekenipp The answer is probably not what you want to hear: Microbes can live on household surfaces for hundreds of
years. The good news, however, is that most don’t. Some well-known viruses, like HIV, live only a few seconds. Microbes, of course, are everywhere. Each square centimeter of skin alone harbors about 100,000 bacteria. And a single sneeze can spray droplets infested with bacteria and viruses as far as 3 feet. The microbial life span depends on many factors, says Philip Tierno, director of microbiology and diagnostic immunology at the New York University School
of Medicine. Because viruses must invade cells of a living host to reproduce, their life spans outside are generally shorter than that of bacteria, which reproduce on their own. Although viruses can survive outside a host on household surfaces, their ability to duplicate themselves is compromised-shortening the virus’s life span. Humidity also makes a difference; no bacteria or virus can live on dry surfaces with a humidity of less than 10 percent. Any sort
of nutrients-food particles, skin cells, blood, mucus-helps microbes thrive, which is why your kitchen sponge is a breeding ground. Bacteria called mesophiles, such as the tuberculosis-causing Mycobacterium tuberculosis, survive best at room temperature and are likely to thrive longer than cold-loving psychrophiles or heat-loving thermophiles. According to Tierno, at room temperature and normal humidity, Escherichia coli (E. coli), a bacteria found in ground
beef that causes food poisoning, can live for a few hours to a day. The calicivirus, the culprit of the stomach flu, lives for days or weeks, while HIV dies nearly instantly upon exposure to sunlight. Other microbes form exoskeleton-like spores as a defense mechanism, like the bacteria Staphylococcus aureus, which is responsible for toxic shock syndrome, food poisoning, and wound infections. In this way, they can withstand temperature and humidity extremes. Tierno says this bacterial spore can
survive for weeks on dry clothing using sloughed skin cells for food. The Bacillus anthracis, the anthrax bacteria, can also form spores and survive tens to hundreds of years. Worried that your home is a hospitable habitat? Tierno says simple hand washing can greatly reduce your risk of picking up germs. Using a disinfectant on high-traffic surfaces-doorknobs, kitchen counters, and sinks-also helps eliminate unwanted household guests. Edited by Bob Sillery
Alvin, Texas
Research by Reed Albergotti and Emily Bergeron
The COVID-19 pandemic has made us change our hygiene practices. We’re washing our hands more often and we’re more aware of how germs are spread, and how we can stop them from spreading.
Many of us have also started cleaning our household surfaces more regularly. So, you may be wondering how long viruses and bacteria can live on these surfaces.
Read on to learn about the different types of germs that can make us ill, how long they can live on surfaces, and what you can do to avoid them.
Cold viruses
If you catch a
, it’s usually because your hands have come into contact with the nasal fluid (secretions) from someone who’s infected with the cold virus.
This includes touching surfaces that are contaminated with a person’s germs: the virus then stays on your hands and can get into your body if you touch your eyes, nose, or mouth.
Cold viruses can live on your hands and other surfaces like cups and plates, cutlery, door handles, keyboards, phones, and worktops for up to 24 hours.
Flu virus
(influenza) is a viral infection that you can catch by breathing in droplets from an infected person after they sneeze, cough, or talk.
Like with a cold, you can also get flu from direct contact with an infected person’s nasal secretions, or by touching objects or surfaces that have been contaminated with the virus.
The flu virus can live on all surfaces in your home (including door knobs, tabletops, toilet flush handles, keyboards, phones and soft furnishings), for up to 48 hours, so it’s important to clean these surfaces regularly to stop the spread of flu. It can also live on hands for up to 24 hours, so washing your hands frequently with soap and warm water will also stop the spread.
COVID-19 virus
It's thought that, like other coronaviruses, the coronavirus that causes
is mainly spread through droplets released when an infected person sneezes, coughs or breathes out. If you breathe in these droplets, or they come into contact with your eyes or mouth, you could catch the virus.
If droplets land on something, the coronavirus might be able to survive for a few days on hard surfaces, such as tables and door handles. You could then be infected by touching the surface before touching your eyes, nose, or mouth, but experts say transmission is less likely via contact with surfaces than breathing in droplets.
Coronavirus can live on indoor surfaces for a few days, but after three days there will be a 99% reduction in survival – so minimal risk of catching Covid via contact with surfaces.
Streptococcal bacteria
are caused by a group of bacteria called Streptococcus (‘strep’).
They’re usually spread from one person to another directly: if you breathe in droplets released when another person sneezes or coughs, touch someone who has the bacteria on their skin, or come into contact with an infected wound or skin sore.
Some studies suggest that certain species of Streptococcus can survive for long periods on surfaces, but there’s a lack of evidence about how long they can last.
Stomach viruses and bacteria
Viruses, such as the
, are common causes of stomach bugs (
). Norovirus can last for weeks on surfaces like lift buttons and doorknobs.
Bacteria such as
,
and campylobacter can also cause
.
E. coli is usually spread through contaminated food or water, or contact with infected animals, but it can survive on surfaces like cooking utensils for several months.
MRSA
(methicillin-resistant Staphylococcus aureus) is a type of bacteria that’s resistant to many types of
. It is spread through contact with infected people or contaminated objects.
MRSA can live on dry surfaces including furniture, and gym equipment for months.
How to avoid getting ill from germs on surfaces
There are some general steps you can take every day to help you avoid becoming ill through germs:
- Avoid close contact with people who are unwell with an infectious illness. Read more about .
- , using soap and water or an alcohol-based sanitiser.
- Try not to touch your eyes, nose or mouth.
- Keep your surroundings clean by using common household products to disinfect surfaces.
- Norovirus (the winter vomiting bug) is the most contagious virus, because you shed billions of virus particles when you’re infected. Although you are most infectious in the first few days, you can still be contagious after 2 weeks. Experts suggest disinfecting surfaces or objects that could be contaminated with a bleach-based household cleaner, washing bedding at 60 degrees, flushing away vomit/ faeces, and washing hands thoroughly after going to the toilet, before preparing food or touching contaminated surfaces.
- Flu virus: Flu is also very infectious and you're most likely to pass it on to someone else within five days. However, flu viruses are relatively fragile so standard cleaning and disinfecting are sufficient to kill them off. Disinfectant wipes can be used for frequently touched objects such as phones, keyboards, and door handles.
- Coronavirus: Although you can catch coronavirus from surfaces, experts say this isn’t the main way it is transmitted. Cleaning with household cleaners is generally sufficient unless someone in your household or who has visited your household has tested positive or is ill with coronavirus , in which case you should use disinfectants.
Your health questions answered
Can germs live on clothing?
Germs can get onto clothing from our own bodies, if our clothing touches contaminated objects or food, or from other people. How long they live on clothing depends on the type of germ. Underwear is more likely to have germs on it, as it can carry germs from poo (faeces).
How long do flu germs live on hands?
There’s not much evidence about how long flu germs can live on hands, but one study found that they only live for a few minutes. Most experts think flu spreads mainly through droplets released when infected people cough, sneeze or talk, which then get into the noses or mouths of people nearby. You should wash your hands with soap and water or use alcohol-based sanitiser to help stop the spread of germs.
How long does the flu virus live in the body?
Up to about 11 days. It usually takes about 2 days from picking up the flu to having symptoms, but can take 1 to 4 days. This is called the incubation period. Generally, you can spread the flu (you’re contagious) from 3 to 4 days before you have symptoms. Then you’re usually contagious for 5 to 7 days after first having symptoms.
Key takeaways
- you can become ill if you touch objects and surfaces that are contaminated with viruses or bacteria, then touch your eyes, nose or mouth
- some viruses and bacteria can live on surfaces just for a few hours or a day, while others can survive for a few weeks or even months
- washing your hands properly and often can reduce the spread of germs from contaminated surfaces
- disinfecting household surfaces can also stop the spread of germs that can make you ill