Viruses that cause the common cold, the flu and COVID-19 may be able to infect someone for several hours to days. It depends on factors such as:

• The structure of the virus. Some viruses are better than others at managing temperature, humidity or other conditions.
• The climate and the indoor environment. This includes humidity, airflow, sunlight and temperature.
• The surface the virus lands on. Some viruses remain infectious for longer on hard surfaces. Others stay more infectious on fabrics.

You can catch a virus if you touch something that a person with the virus sneezed or coughed on minutes before.

But close contact with a person who has one of these viruses is the most common way they spread. This includes shaking hands or being close enough to breathe in the virus that a person sends out with a cough or sneeze.

Getting COVID-19 and flu vaccines helps lower the chance that you will catch or spread these viruses or get seriously ill from or die of the illnesses they cause.

You can lower your risk of catching viruses that cause colds, flu and COVID-19 in other ways too:

• Wash your hands. Wash your hands well and often with soap and water for at least 20 seconds. If soap and water aren't available, use an alcohol-based hand sanitizer with at least 60% alcohol.
• Cover your coughs and sneezes. Cough or sneeze into a tissue or your elbow. Then wash your hands.
• Avoid touching your face. Keep your hands away from your eyes, nose and mouth to keep germs away from those places.
• Help from afar. Avoid close contact with anyone who is sick or has symptoms, if possible.
• Clean and disinfect high-touch surfaces. For example, clean doorknobs, light switches, electronics and counters regularly.

If you're sick, stay home for at least 24 hours after your fever is gone. That lowers your chance of infecting others. And if you have symptoms of COVID-19, test for the infection. If you know you've been exposed to the virus that causes COVID-19, test five days after you came in contact with the virus.