How Long do Bacteria and Viruses Live Outside the Body?

It depends on which bacteria or virus is present, the kind of surface they land on, and the surrounding environment, such as whether it is hot, cold, humid, or sunny.

Cold viruses

A wide range of viruses can cause colds, and they can sometimes remain on indoor surfaces for over seven days. Generally, viruses last longer on non-porous surfaces like plastics and stainless steel than on porous materials like tissues and fabrics. Even though cold viruses have been found to survive on surfaces for a few days, their ability to infect people goes down quickly, and they rarely remain a threat beyond 24 hours.

Most viruses that cause colds do not stay on hands for very long. In certain cases, they may survive only a few minutes, but around 40% of rhinoviruses – common cold viruses – are still capable of causing infection on hands after an hour.

Respiratory syncytial virus (RSV), another cold-like virus that can seriously affect children, can persist for up to six hours on door handles and countertops, 30 to 45 minutes on tissues or clothing, and up to 20 minutes on skin.

Flu viruses

Flu viruses that remain infectious on hard surfaces can survive there for up to 24 hours. On tissues, they stay infectious for only around 15 minutes.

Similar to cold viruses, active flu viruses do not remain on the hands for long. After five minutes, the amount of flu virus on hands drops to very low levels.

Flu viruses may also live as tiny droplets in the air for several hours, and low temperatures increase their ability to stay active for this time.

Parainfluenza virus, which causes croup in children, can last on hard surfaces for about 10 hours and on softer surfaces for around four hours.

Stomach bugs

Many different organisms can lead to stomach bugs. These include bacteria like E. coli, salmonella, Clostridium difficile (C. difficile), and campylobacter, as well as viruses such as norovirus and rotavirus.

Salmonella and campylobacter remain on hard surfaces or fabrics for between one and four hours. However, norovirus and C. difficile can remain active far longer. One study found that C. difficile can stay viable for five months, and norovirus may remain on hard surfaces for days or even weeks.

If a person with norovirus vomits, the virus is released in tiny droplets into the air, which can then land on surfaces. This is why it is crucial to clean surfaces thoroughly if someone in your household has norovirus.

Most germs can be effectively removed using soap and water. Thorough hand washing and safe food handling, especially after using the bathroom, help reduce the spread of these bugs.

MRSA

The staphylococcus aureus bacteria responsible for MRSA can live on surfaces for several days to weeks. MRSA bacteria often last longer than certain other bacteria and viruses because they survive well without moisture. They also tend to remain on hard surfaces for longer periods compared to soft surfaces.

Herpes

The herpes virus, which is behind cold sores and genital herpes, dies off very fast once it is away from the skin. It is typically transferred through direct contact, like kissing or oral sex, while the virus is active on the skin.

Preventing the spread of infection

It is not always possible to avoid getting sick, but there are steps you can take to lessen the chance of spreading or catching an infection:

• Wash hands often, especially after using the bathroom, before preparing food, and after coughing, sneezing, or blowing your nose.
• Maintain a clean and hygienic home, especially if a family member is ill.
• Wash possibly contaminated fabrics at 60°C (140°F) using a product containing bleach.