A cold is a viral infection that affects the upper respiratory tract, including the nose, throat, and lungs. Common symptoms include a runny or stuffy nose, sore throat, sneezing, coughing, mild headache, and a low-grade fever. Colds usually last about a week, but symptoms can persist longer in children, older adults, or people with weakened immune systems. Adults typically experience two to three colds per year, while children often have more.

Colds spread easily through respiratory droplets or by touching contaminated surfaces and then touching your face. While over 200 viruses can cause colds, six are most commonly responsible.

1. Rhinovirus

Rhinovirus is the leading cause of the common cold, accounting for up to half of all cases. It spreads most frequently in crowded places like schools and public transportation and tends to peak in the early fall and spring.

Symptoms of Rhinovirus Cold:

  • Cough

  • Mild sore throat

  • Runny or stuffy nose

  • Sneezing

  • Mild fever (sometimes)

Rhinoviruses usually cause mild illness that resolves in 7 to 10 days. However, they can sometimes lead to complications such as ear infections, sinus infections, or respiratory problems, particularly in individuals with asthma or allergies.

2. Coronavirus (Common Cold Version)

Before the emergence of COVID-19, some types of coronaviruses were already known to cause seasonal colds, accounting for about 15% of cases. These coronaviruses are typically mild and most active in winter but can circulate year-round.

Unlike COVID-19, these cold-causing coronaviruses generally do not require testing or medical intervention and usually resolve at home.

Symptoms of Coronavirus Cold:

  • Mild cough

  • Runny nose

  • Sneezing

  • Sore throat

  • Occasional low-grade fever

  • Stomach discomfort (less common)

In people with weakened immune systems, coronavirus colds may result in more severe illness such as pneumonia.

3. Enterovirus

Enteroviruses are a large group of over 300 viruses, including rhinoviruses and coxsackieviruses. Some, like enterovirus D68 and coxsackievirus, can cause respiratory symptoms. Others cause non-respiratory illnesses but may still present with cold-like symptoms.

Respiratory Symptoms of Enterovirus:

  • Cough

  • Fever

  • Runny nose

  • Sore throat

  • Wheezing

  • Pneumonia (in severe cases)

Non-Respiratory Symptoms:

  • Fever

  • Malaise

  • Gastrointestinal upset

  • Skin rashes

  • Swollen lymph nodes

  • Muscle weakness

Enteroviruses can cause both mild colds and more serious illnesses such as hand, foot, and mouth disease or aseptic meningitis.

4. Human Parainfluenza Virus (HPIV)

Human parainfluenza virus can cause both upper and lower respiratory tract infections, particularly in young children, older adults, and people with compromised immune systems. There are four HPIV types, each peaking during different seasons.

Types 1 and 3 are more likely to cause severe illness, such as croup, bronchiolitis, and pneumonia.

Symptoms of HPIV Infection:

  • Fever

  • Sore throat

  • Runny or stuffy nose

  • Cough or croup

  • Wheezing, chest pain, or shortness of breath

Croup, common in children aged 3–5, is characterized by a barking cough, hoarseness, and breathing difficulty. Bronchiolitis and pneumonia may also occur, depending on age and immune health. Tracheobronchitis, a milder inflammation of large airways, causes coughing and chest congestion.

5. Adenovirus

Adenoviruses cause cold symptoms that often last longer than those from other viruses—sometimes persisting for weeks or even months. These viruses spread quickly in crowded places like schools and daycares.

Symptoms of Adenovirus Cold:

  • Runny nose

  • Cough

  • Sore throat

  • Fever

In addition to cold symptoms, adenovirus can cause conjunctivitis (pink eye), diarrhea, and even bronchitis, a condition that inflames the airways and causes chest discomfort and difficulty breathing.

6. Human Metapneumovirus (HMPV)

HMPV primarily affects children under two, though most children are infected with it at least once by age five. It is most common in late winter and early spring.

While healthy adults may experience only mild symptoms, infants under six months and individuals with chronic illnesses may develop severe respiratory symptoms.

Symptoms of HMPV Infection:

  • Cough

  • Runny nose

  • Fever

  • Sore throat

  • Wheezing or breathing difficulty (in severe cases)

HMPV can lead to bronchiolitis or pneumonia, especially in high-risk individuals.

How To Know Which Type You Have

It’s difficult to determine exactly which virus is causing your cold without lab testing, which is usually unnecessary unless symptoms are severe. Certain patterns may offer clues:

  • A barking cough may suggest croup from parainfluenza.

  • A cold with pink eye may point to adenovirus.

  • Long-lasting symptoms may be due to adenovirus or enteroviruses.

If symptoms become severe or unusual, a healthcare provider may order specific tests to identify the virus.

When To See a Healthcare Provider

Most colds improve within 1 to 2 weeks and can be managed at home. However, seek medical attention if you or your child experiences:

  • A cough that worsens while other symptoms improve

  • Flare-up of a chronic condition (like asthma)

  • High fever or fever lasting more than 4 days

  • Signs of dehydration (dry mouth, decreased urination)

  • Severe symptoms or symptoms lasting longer than 10 days

Colds can occasionally lead to serious complications such as ear infections, pneumonia, sinusitis, or exacerbation of chronic diseases.

Emergency care is needed for difficulty breathing, persistent high fever, or signs of severe dehydration.

Preventing Colds

There’s no vaccine for the common cold, but prevention is possible with good hygiene and lifestyle habits:

  • Wash your hands regularly with soap and water

  • Use hand sanitizer when soap isn’t available

  • Avoid touching your face with unwashed hands

  • Clean frequently touched surfaces

  • Cover your mouth and nose when sneezing or coughing

  • Avoid close contact with sick individuals

  • Get enough sleep and manage stress

  • Eat a balanced diet and stay physically active

  • Consider immune-support supplements like vitamin C, zinc, or elderberry (after consulting your provider)

If you’re sick, stay home to avoid spreading the virus to others.

A Quick Review

While over 200 viruses can cause the common cold, six major ones account for most cases: rhinovirus, coronavirus (common cold strains), enteroviruses, parainfluenza, adenovirus, and human metapneumovirus.

These viruses cause similar symptoms like runny nose, sore throat, and cough. However, some can result in more serious complications—especially in young children, older adults, or people with weakened immune systems.

Good hygiene, awareness of risk factors, and early intervention when needed can help you stay healthy and reduce the spread of colds.