What Is Parainfluenza?

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Parainfluenza is a common virus that can cause both upper and lower respiratory infections, including colds, bronchitis, croup, and pneumonia. Despite the name, it is not related to influenza (the flu). It is caused by an entirely different virus known as the human parainfluenza virus (HPIV).

There are four different types of HPIV:

  • HPIV-1: the leading cause of croup in children
  • HPIV-2: also a common cause for croup typically seen in autumn
  • HPIV-3: associated with pneumonia, bronchitis, and bronchiolitis
  • HPIV-4: a less common type associated with more severe illness

Symptoms vary depending on both the viral type and individual. Parainfluenza symptoms are most severe in infants, persons with weakened immune systems, and the elderly.


As with the cold and flu, parainfluenza can be easily passed from person to person. The virus itself is quite robust and can live on surfaces for up to 10 hours. As a result, it can spread rapidly through kindergarten and elementary schools.

To prevent the spread of infection, the same rules for the cold or flu apply:

  • Wash your hands after coming into contact with a cold or flu sufferer.
  • Clean any objects and surfaces the ill person may have touched.
  • If you are ill, cover your mouth when you cough or sneeze.
  • Keep a child from school if he or she is sick.


After exposure, it takes between two to seven day for symptoms to develop, the most common of which include:

  • Sore throat
  • Cough
  • Sneezing
  • Fever
  • Shortness of breath
  • Wheezing
  • Congestion
  • Ear pain
  • Chest pain
  • Lack of appetite

In most cases, symptoms are not severe and may be similar to the common cold. Sometimes, however, symptoms can progressively worsen and may lead to infections in the main bronchial tube of the lungs (bronchitis), the smaller air passages (bronchiolitis), or the lung itself (pneumonia).


In otherwise healthy people, parainfluenza is typically diagnosed by symptoms and ruling out other causes. Those with compromised immune systems may undergo additional testing to determine the strain. Your doctor may also take a throat culture or nasal swab to rule out other pathogens, such as influenza A.

After examining you and listening to your lungs, your doctor may order imaging tests, such as a chest X-ray or CT-scan, to check for pneumonia and determine the right course of treatment for you.


Parainfluenza is typically treated symptomatically. If the symptoms are mild, there is usually no need for medical intervention. In cases of fever or body aches, acetaminophen or an over-the-counter cold and flu remedy may be used. (For children and adolescents, aspirin should be avoided.)

A parainfluenza infection can sometimes turn serious in younger children, especially those under 18 months. In cases of wheezing or breathing difficulty, nebulizer medications such as Pulmicort may be used to help relax and open the air passages. In the event of respiratory distress, oral steroids or a shot of epinephrine may be prescribed. Secondary pneumonia is typically be treated with antibiotics.

A Word From Verywell

Parainfluenza is more common than most of us realize and, in most cases, is not of great concern. In fact, most people won't know whether they've caught a cold or HPIV, and it usually doesn't matter. However, if symptoms worsen or persist, don't hesitate to seek medical attention.

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Article Sources

Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial policy to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Centers for Disease Control and Prevention. About Human Parainfluenza Viruses (HPIVs) Symptoms and Illnesses.

  2. NHS. How long do bacteria and viruses live outside the body?

  3. Centers for Disease Control and Prevention. Human Parainfluenza Viruses (HPIVs) Prevention and Treatment.

  4. Falsey AR. Current management of parainfluenza pneumonitis in immunocompromised patients: a reviewInfect Drug Resist. 2012;5:121–127. doi:10.2147/IDR.S25874