How Long Is a Cold Contagious?

If you have a cold, you're usually the most contagious during the first four days of symptoms. However, some viral strains can continue to spread for up to a month.

Each year, millions of cases of the common cold occur in the United States. According to the Centers for Disease Control and Prevention (CDC), hundreds of different cold viruses spread easily from person to person.

The common cold is an almost inevitable part of life and can be difficult to avoid. Understanding the risk of transmission and taking proper precautions can help stem the spread of colds.

This article explains how colds are spread and when they are the most contagious. It also discusses ways to lower your odds of catching a cold and how to prevent spreading a cold to a loved one.

How Long Are You Contagious?

The incubation period for a cold virus is 24 to 72 hours. This is how long it takes for symptoms to appear after you become infected. For the common cold, symptoms start to develop one to three days after exposure to the virus.

Colds are most contagious one to four days after symptoms develop. Common cold symptoms include:

• Congestion
• Coughing
• Headache
• Runny nose
• Sore throat

Not everyone gets all these symptoms, and the severity can vary.

Most colds last for about a week, but it's possible to spread the virus after that. Cold viruses can persist in the body for up to four weeks.

While the risk of transmission decreases rapidly over time, infecting others may still be possible even if you no longer have symptoms.

How Are Colds Contagious?

Cold viruses are spread through airborne droplets, person-to-person contact, and contact with contaminated surfaces.

When a person is sick with a respiratory virus, coughing and sneezing propel droplets into the air. The virus-loaded droplets land on surfaces or enter someone else's upper respiratory tract.

Cold viruses can live on surfaces for several hours, making it possible to become infected if you touch a contaminated surface and then your nose. This is referred to as fomite transmission.

Most colds are caused by strains in the rhinovirus and coronavirus families. Adenovirus, metapneumovirus, parainfluenza, and respiratory syncytial virus (RSV) are other viruses that cause upper respiratory symptoms.

Prevention Tips

If you get a cold, the best way to avoid spreading the virus is to isolate yourself. When around others, it helps to wear a face mask to catch respiratory droplets if you cough or sneeze. People who live with you can do the same.

Be sure to cover your mouth when coughing or sneezing. It is best to cough or sneeze into the crook of your arm; in this way, you can avoid contaminating your hand. You can cough or sneeze into a tissue but will need to wash your hands afterward (or use an alcohol-based hand sanitizer).

You and others in your household should frequently wash your hands and regularly clean surfaces. Try your best to avoid touching your face (like scratching or rubbing your nose).

It's especially important to take these precautions when you are in contact with people who are at an increased risk of complications. These include:

• Infants or toddlers
• Older adults
• Persons with asthma
• People with weakened immune systems

While a cold may not necessarily be worse in these individuals, your symptoms may turn out to be something more dangerous, like the flu or COVID-19. To be safe around high-risk people, continue to use precautions for a week after cold symptoms abate.

What To Do If You Are Exposed

While there are no vaccines to prevent colds or surefire ways to avoid cold symptoms, there are things you can do that may reduce the severity or duration of a cold. These include:

• Getting plenty of rest
• Increasing fluid intake to prevent dehydration
• Sipping warm tea, warm soup, or warm apple juice to loosen congestion
• Using a cool-mist vaporizer or humidifier
• Gargling with salt water to relieve a sore throat
• Using over-the-counter saline nasal drops or sprays to treat a stuffy nose
  

Summary

Colds are spread by airborne droplets, person-to-person contact, and touching contaminated surfaces. Colds are most contagious one to four days after cold symptoms appear but may be contagious even longer.

If you get a cold, you can prevent the spread of the virus by isolating yourself, wearing a face mask, covering your mouth when coughing or sneezing, washing your hands frequently, and regularly cleaning surfaces.

Treating a cold properly, including getting plenty of rest, may reduce its duration or severity.

A Word From Verywell

No one enjoys catching a cold, but by taking a few standard precautions, you may be able to avoid spreading the virus to others. Out of courtesy to others, taking time off from work or school is best if you have cold symptoms.

The same applies if you are scheduled to go to an event or location where there will be a lot of people, such as a concert or a movie theater. Even if you're not entirely sure you are sick, you should avoid going out as you may inadvertently be the cause of a super-spreader event.