What is the common cold?

The common cold is a viral infection that affects the nose and throat (the upper respiratory tract). Although colds are common and usually harmless, they can be uncomfortable and keep you in bed for a few days.

Catching the common cold¹ is the main reason for children and adults missing school and work. In the United States, there are millions of cases of the common cold each year.

Colds are very common, generally mild, and have treatable symptoms.

Common cold symptoms

Although there are multiple types of viruses that can cause a cold, rhinoviruses² are the most common culprits. Rhinoviruses are most active in early fall, spring, and summer, and are responsible for roughly 30–50% of colds.

The coronavirus³ can also cause cold symptoms. This virus is treated much in the same way as the rhinovirus. The coronavirus is most active in the winter and early spring, and causes about 20% of cold infections.

Respiratory syncytial virus (RSV)⁴ is a common and very contagious respiratory infection that affects most babies before their second birthday. While RSV poses a small risk for complications, it usually causes nothing more than cold-like symptoms in adults. However, RSV can become more serious in infants and young children—especially if they possess certain risk criteria like chronic lung disease or congenital heart disease. RSV bronchiolitis⁵ in children can lead to hospitalizations when they present with respiratory distress.

Common cold risk factors

The following risk factors can increase your chances of getting a cold:

• Age: children under 6 years of age are at the greatest risk of getting colds, especially if they spend time in crowded settings, such as daycare centers.
• Weakened immune system: people with chronic illnesses or weakened immune systems (for example, someone with an autoimmune disorder) are highly susceptible to catching viruses like the common cold.
• Time of year: both children and adults are most likely to catch colds in the fall and winter. However, it’s still possible to catch a cold at any time of year.
• Smoking: you’re more likely to catch a cold—and have more severe colds—if you’re regularly exposed to cigarette smoke.
• Exposure: being in crowded places, such as at school, at work, or in public transportation, can increase your risk of catching a cold. Make sure to wash your hands frequently and avoid people who you know are sick with a cold.

Common cold causes

While most people catch colds in the fall and winter, it’s possible to get a cold at any time of year.

A cold virus can spread through direct person-to-person contact. The virus enters your body through your mouth, eyes, or nose. You can catch a cold from particles in the air left behind by an infected person’s cough or sneeze. Droplets left behind on surfaces touched by infected persons can also cause you to catch the virus.

The likelihood of catching the common cold increases in crowded places, like schools, daycare centers, public transportation, or workplaces. Because the common cold is often spread through large groups of people in close contact, the beginning of the school year can present a higher risk of you or your child contracting a cold.

If you think you have a cold, avoid going into public places and spreading the infection to others.

There is a common and persistent myth that you can get the common cold from spending time outside in cold weather. This is not the case, as a cold is always caused by catching a virus.

Who can get the common cold?

Children under 6 years old are at the greatest risk of catching a cold. However, healthy adults can also catch a cold at any time. Adults can generally expect to get 2–3 colds each year.

People with weakened immune systems (such as those with autoimmune disorders), asthma, or respiratory conditions (like COPD) run the risk of developing serious illnesses such as bronchitis or pneumonia⁶ as well.

Common cold symptoms

Symptoms of the common cold generally appear 1–3 days after being infected by the virus.

While signs and symptoms of a cold can vary from person to person, they usually include:

• A runny or stuffy nose (congestion⁷)
• Sore throat (pharyngitis⁸)
• Cough
• Slight body aches
• Mild headache
• Sneezing
• Low-grade fever⁹
• General malaise (feeling unwell)

When you have a runny or stuffy nose, the mucus or discharge may become thick and yellow or green in color as a cold runs its course. This generally isn’t an indication of a bacterial infection and is not a cause for alarm.

Many adults infected with the common cold may recover completely within 7–10 days, while most children recover in 10–14 days. Symptoms might last longer in individuals who are immunocompromised or those who smoke.

If symptoms don’t improve (or worsen after getting better), seek medical care. It is always best to check with your healthcare provider when you are unsure about your symptoms or illness.

Serious symptoms of a cold

In adults, seek medical attention if you have:

• A fever higher than 101°F (38.3°C)
• A fever lasting 5 or more days, or a fever that returns after you are afebrile (do not have a fever)
• Shortness of breath
• Wheezing
• Severe sore throat, headache, or sinus pain

For parents, you should seek immediate medical attention if your child has:

• A fever of 100.4°F (38°C) in newborns up to 12 weeks old
• A rising fever or a fever lasting more than two days
• Symptoms that worsen or don’t get better
• Severe symptoms, like a headache or cough
• Wheezing
• Ear pain
• Extreme mental fog
• Unusual drowsiness
• Lack of appetite

Complications from the common cold

Sometimes, the common cold causes secondary complications that can range in severity. You should consult your provider if you or your child have any of the following:

• Acute ear infection¹⁰ (acute otitis media) occurs when the cold virus enters the space behind the eardrum. Symptoms of an ear infection include earaches and, sometimes, pus discharge from the ear or a returning fever following a cold.

• Asthma¹¹: Colds can sometimes trigger asthma attacks. If you or your child has asthma, it’s important to monitor respiratory function and used prescribed inhalers as needed.

• Acute sinusitis¹²: A common cold that doesn’t get better can cause inflammation and infection of the sinuses (sinusitis) in both adults and children.

• Other secondary infections, including strep throat¹³ (streptococcal pharyngitis), pneumonia, and croup¹⁴ or bronchitis in children. These infections must be treated by a healthcare provider.