The common cold is a viral infectious disease that infects the upper respiratory system. It is also known as acute viral rhino pharyngitis and acute coronary.
It is the most common infectious disease in humans and is mainly caused by corona viruses or rhinoviruses.
Because there are more than 200 viruses that cause the common cold, the human body can never build up resistance to all of them. This is why colds are so common and often return. According to the CDC (Centers for Disease Control and Prevention), adults get 2–3 colds per year, and children may have up to 12 per year.
The common cold is contagious; it can be spread by air droplets from coughs and sneezes and by touching infected surfaces. It is contagious from 1–2 days before symptoms begin until the symptoms have stopped.
Fast facts on colds
Here are some key points about colds. More detail and supporting information is in the main article.
- Common cold symptoms include dry or sore throat, blocked or runny nose, and sneezing.
- Around a quarter of people do not experience symptoms when infected with a cold.
- Up to half of common colds are caused by a group of viruses referred to as rhinoviruses.
- Complications of the common cold include acute bronchitis and pneumonia.
- People with lung conditions such as asthma and chronic obstructive pulmonary disease are more vulnerable to colds than other people.
The common cold is a viral infection of your nose and throat (upper respiratory tract). It’s usually harmless, although it might not feel that way. Many types of viruses can cause a common cold.
Children younger than 6 are at greatest risk of colds, but healthy adults can also expect to have two or three colds annually.
Most people recover from a common cold in a week or 10 days. Symptoms might last longer in people who smoke. If symptoms don’t improve, see your doctor.
Symptoms of a common cold usually appear one to three days after exposure to a cold-causing virus. Signs and symptoms, which can vary from person to person, might include:
- Runny or stuffy nose
- Sore throat
- Slight body aches or a mild headache
- Low-grade fever
- Generally feeling unwell (malaise)
The discharge from your nose may become thicker and yellow or green in color as a common cold runs its course. This isn’t an indication of a bacterial infection.
When to see a doctor
For adults — seek medical attention if you have:
- Fever greater than 101.3 F (38.5 C)
- Fever lasting five days or more or returning after a fever-free period
- Shortness of breath
- Severe sore throat, headache or sinus pain
For children — in general, your child doesn’t need to see the doctor for a common cold. But seek medical attention right away if your child has any of the following:
- Fever of 100.4 F (38 C) in newborns up to 12 weeks
- Rising fever or fever lasting more than two days in a child of any age
- Symptoms that worsen or fail to improve
- Severe symptoms, such as headache or cough
- Ear pain
- Extreme fussiness
- Unusual drowsiness
- Lack of appetite
Although many types of viruses can cause a common cold, rhinoviruses are the most common culprit.
A cold virus enters your body through your mouth, eyes or nose. The virus can spread through droplets in the air when someone who is sick coughs, sneezes or talks.
It also spreads by hand-to-hand contact with someone who has a cold or by sharing contaminated objects, such as utensils, towels, toys or telephones. If you touch your eyes, nose or mouth after such contact or exposure, you’re likely to catch a cold.
These factors can increase your chances of getting a cold:
- Age. Children younger than 6 are at greatest risk of colds, especially if they spend time in child-care settings.
- Weakened immune system. Having a chronic illness or otherwise weakened immune system increases your risk.
- Time of year. Both children and adults are more susceptible to colds in fall and winter, but you can get a cold anytime.
- Smoking. You’re more likely to catch a cold and to have more-severe colds if you’re exposed to cigarette smoke.
- Exposure. If you’re around many people, such as at school or on an airplane, you’re likely to be exposed to viruses that cause colds.
- Acute ear infection (otitis media). This occurs when bacteria or viruses enter the space behind the eardrum. Typical signs and symptoms include earaches and, in some cases, a green or yellow discharge from the nose or the return of a fever following a common cold.
- Asthma. A cold can trigger an asthma attack.
- Acute sinusitis. In adults or children, a common cold that doesn’t resolve can lead to inflammation and infection of the sinuses (sinusitis).
- Other secondary infections. These include strep throat (streptococcal pharyngitis), pneumonia, and croup or bronchiolitis in children. These infections need to be treated by a doctor.
There’s no vaccine for the common cold, but you can take commonsense precautions to slow the spread of cold viruses:
- Wash your hands. Clean your hands thoroughly and often with soap and water, and teach your children the importance of hand-washing. If soap and water aren’t available, use an alcohol-based hand sanitizer.
- Disinfect your stuff. Clean kitchen and bathroom countertops with disinfectant, especially when someone in your family has a cold. Wash children’s toys periodically.
- Use tissues. Sneeze and cough into tissues. Discard used tissues right away, then wash your hands carefully. Teach children to sneeze or cough into the bend of their elbow when they don’t have a tissue. That way they cover their mouths without using their hands.
- Don’t share. Don’t share drinking glasses or utensils with other family members. Use your own glass or disposable cups when you or someone else is sick. Label the cup or glass with the name of the person with the cold.
- Steer clear of colds. Avoid close contact with anyone who has a cold.
- Choose your child care center wisely. Look for a child care setting with good hygiene practices and clear policies about keeping sick children at home.
- Take care of yourself. Eating well, getting exercise and enough sleep, and managing stress might help you keep colds at bay.
What is the common cold? What causes the common cold?
The common cold is a self-limited contagious disease that can be caused by a number of different types of viruses. The common cold is medically referred to as a viral upper respiratory tract infection. Symptoms of the common cold may include cough, sore throat, low-grade fever, nasal congestion, runny nose, and sneezing. More than 200 different types of viruses are known to cause the common cold, with rhinovirus causing approximately 30%-40% of all adult colds. Rhinovirus multiplies best at temperatures found in the nose. Rhinovirus infection rates peak from September to November and March to May. Nevertheless, rhinovirus may cause disease at any time of year. During peak periods, up to 80% of colds may be due to rhinovirus.
Other commonly implicated viruses include corona virus, adenovirus, respiratory syntactical virus, and para influenza virus. Because so many different viruses can cause the common cold, and because new cold viruses constantly develop, the body never builds up resistance against all of them. For this reason, colds are a frequent and recurring problem. In fact, children in preschool and elementary school can have six to 12 colds per year while adolescents and adults typically have two to four colds per year. The common cold occurs most frequently during the fall, winter, and spring.
The common cold is the most frequently occurring viral infection in the world, and it is a leading cause of doctor visits and missed days from school and work. It is estimated that individuals in the United States suffer an estimated 1 billion colds per year, with approximately 22 million days of school absences recorded annually. In the United States, the common cold is thought to account for approximately 75-100 million physician visits annually, with an economic impact of greater than $20 billion per year due to cold-related work loss.
How does the common cold spread?
The common cold is spread either by direct contact with infected secretions from contaminated surfaces or by inhaling the airborne virus after individuals sneeze or cough. Person-to-person transmission often occurs when an individual who has a cold blows or touches their nose and then touches someone or something else. A healthy individual who then makes direct contact with these secretions can subsequently become infected, often after their contaminated hands contact their own eyes, nose, or mouth. A cold virus can live on frequently touched objects such as doorknobs, pens, books, cell phones, computer keyboards, and coffee cups for several hours and can thus be acquired from contact with these objects.
How long is the common cold contagious?
In general, the common cold can be contagious anywhere from one to two days before the symptoms begin up until the symptoms have completely resolved. However, the common cold is typically most contagious during the initial two to three days of illness.
What are risk factors for acquiring the common cold?
There are various risk factors that may increase the chances of acquiring the common cold, including the following:
- Age: Infants and young children are more likely to develop the common cold because they have not yet developed immunity to many of the implicated viruses.
- Seasonal variation: Individuals more commonly acquire the common cold during the fall, winter, or during the rainy season (in warmer climates). This is felt to occur because people tend to stay indoors and are in closer proximity to one another.
- Weakened immune system: Individuals with a poorly functioning immune system are more likely to develop the common cold. Also, individuals with excessive fatigue or emotional distress may be more susceptible to catching the common cold.
What are the symptoms and signs of the common cold in adults, children, and infants? What is the incubation period of the common cold?
Common cold symptoms typically begin two to three days after acquiring the infection (incubation period), though this may vary depending on the type of virus causing the infection. Individuals also tend to be most contagious during the initial two to three days of having symptoms. Cold viruses target mainly the upper respiratory tract (nose, sinuses, and throat). Symptoms and signs of the common cold may also vary depending on the virus responsible for the infection and may include
Does it have anything to do with exposure to cold weather?
Though the common cold usually occurs in the winter months, the cold weather itself does not cause the common cold. Rather, it is thought that during cold-weather months, people spend more time indoors near each other, thus facilitating the spread of the virus. For this same reason, children in day care and school are particularly prone to acquiring the common cold. The low humidity during these colder months is also felt to contribute to the increased prevalence of the common cold, as many of the implicated viruses seem to survive better in low-humidity conditions.
What are the stages of the common cold?
Because the common cold can be caused by so many different viruses, the progression and severity of symptoms vary from individual to individual. In general, symptoms will develop two to three days after the virus is contracted. Some individuals will develop very mild symptoms whereas others will develop more severe symptoms. The type of symptoms will also vary, with some individuals developing only nasal congestion, while others may develop many or all of the symptoms described above. The symptoms that develop also depend on the underlying health of the person infected.
Most colds will resolve after seven to 10 days, though some individuals experience a shorter course and others a more prolonged illness, again depending on the particular virus involved, as well as the infected person’s underlying health issues.