A cough may linger following a virus such as a cold or the flu. After ruling out other issues, the doctor may diagnose a ‘postviral cough.’ Experts are unsure exactly why this happens, but there are a few possible causes.

By definition, a postinfectious cough is one that lingers after an upper respiratory tract infection for 3–8 weeks after recovery from other symptoms, according to scientists. A postviral cough refers specifically to a cough that persists after a viral infection.

However, a cough can persist for months after infection with COVID-19.

There is no specific treatment for this type of cough.

Here, learn more about a cough that continues after recovery from a viral infection such as the flu. We look into the causes, treatments, and when to see a doctor.

a man sat on a bus with a cough that he still has after the fluShare on Pinterest
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A cough may linger after a person has recovered from a viral infection. A doctor may call this a postinfectious or postviral cough.

According to a 2017 review, a postviral cough is one that lingers after recovery from a viral infection, such as a cold or flu. It typically disappears on its own after a few days, though it can last longer. If it continues for 3 weeks or more, a doctor will consider it persistent.

A 2016 review reports that postviral coughs sometimes last 3–8 weeks.

For more information and resources to help keep you and your loved ones healthy this flu season, visit our dedicated hub.

A cough may persist after recovery from a range of viral infections, and various underlying conditions can increase the risk.

Respiratory infections

Beyond the flu, the following infections can lead to a postviral cough:

A lingering cough can occur after pertussis or whooping cough. This is a postinfectious cough. However, the cause is bacterial, not viral.

Experts believe a postviral cough may stem from increased sensitivity of cough receptors in the body or temporary bronchial hyper-responsiveness. It may be linked to damage in the cells that line the airways during the initial infection.

Excess mucus production may also contribute.

In 2021, scientists investigating a postinfectious cough after COVID-19 suggested that nerve involvement — including nerve inflammation due to the inflammatory response — may result in cough hypersensitivity.

Other underlying medical conditions

Other health issues can cause a cough to linger after a person recovers from an infection.

In this case, the cough may be linked to the underlying condition and not the infection. In other words, it is not a postviral cough.

Asthma

Asthma causes the airways to become swollen and sensitive.

If a person with asthma develops the flu, there will be additional inflammation in the airways. This can trigger asthma attacks or worsen asthma symptoms.

People may not be aware that they have asthma. Because the symptoms can be very mild, it may be easy to mistake them for persistent effects of a respiratory infection, for example.

Other symptoms of asthma include:

  • difficulty breathing
  • chest tightness
  • wheezing
  • shortness of breath

Laryngeal pharyngeal reflux

Laryngeal pharyngeal reflux (LPR) involves acid from the stomach traveling up through the esophagus and into the throat.

The acid tends to irritate and inflame the vocal cords, and a cough is a common symptom of this issue, according to the International Foundation for Gastrointestinal Disorders.

A person with this reflux may find it hard to identify the cause of their cough, as LPR often begins after an upper respiratory illness, the Foundation reports.

Other symptoms of LPR may include:

  • frequent throat clearing
  • hoarseness
  • a feeling that something is stuck in the throat

Obstructive sleep apnea

According to 2015 research, obstructive sleep apnea (OSA) can cause a chronic cough. The connection remains unclear. However, it may involve OSA causing:

  • airway inflammation
  • gastroesophageal reflux disease, or GERD
  • cough reflex sensitivity

Symptoms of OSA include:

Anyone experiencing a persistent cough after a viral infection should consult a doctor.

The doctor may perform a physical examination and ask about other symptoms. The person should let the doctor know about any recent infections.

They may order an X-ray of the chest to look for signs of any underlying condition that could be causing the cough.

To check for any current infection, the doctor may run tests on a sample of sputum, the thick substance that the lungs create during an upper respiratory infection.

If the doctor has ruled out other possible underlying causes, they may diagnose postviral cough. This issue may last 3–8 weeks.

To help ease a cough at home, a person can try:

  • drinking water, warm broths, and teas to stay hydrated
  • drinking lemon and honey (not suitable before the age of 12 months)
  • avoiding irritants such as pollen, smoke, and dust
  • using a humidifier
  • breathing in steam from a hot shower or bath to open the airways
  • avoiding or quitting smoking
  • practice abdominal breathing

To prevent a cough before speaking, try the following:

  1. Relax the shoulders, jaw, and tongue.
  2. Take a gentle slow breath in through the nose.
  3. Breathe out through pursed lips.

If these techniques do not work, a doctor may recommend over-the-counter or prescription medications.

Some that can relieve a postviral cough include:

  • antihistamines
  • decongestants
  • cough suppressants
  • ipratropium, a prescription inhaled medication that helps open the airway

In 2020, some researchers noted there was a lack of evidence to support any specific treatment. They are looking at whether corticosteroids may help by reducing inflammation.

As always, it is important to review any current medications with the doctor.

A postviral cough can clear within a few days or weeks without treatment. However, anyone with concerns about the cause of a cough should consult a healthcare professional.

It is also important to let a doctor know if treatments are not working. They may be able to recommend other options.

If a postviral cough lasts longer than 8 weeks, speak with the doctor, as there may be a different underlying cause.

Here are some questions people often ask about a postviral cough.

How long does a postviral cough last?

A postinfectious cough is one that lingers for 3–8 weeks after an upper respiratory tract infection. However, in people who have had a COVID-19 infection, a cough may persist for weeks or months.

Is postviral cough serious?

The cough itself is not usually dangerous. However, it can affect a person’s quality of life and overall well-being. It may also be a sign of other complications.

People with a long-term cough after COVID-19, for example, may have other symptoms of “long COVID.” An ongoing cough may also indicate another illness that needs attention, such as asthma or lung cancer.

Is a postviral cough contagious?

It is not possible to transmit a virus through a postviral cough. After a cold, for instance, a person may have a cough for several weeks. However, they can only pass it on for up to 2 weeks after the infection begins.

How do I get rid of a lingering cough?

There is no specific treatment for a postinfectious cough. Doctors may prescribe various drugs. However, there is little evidence that they are consistently effective. Home remedies include staying hydrated and using a humidifier.

A postviral cough is one that lingers after a person has recovered from a viral infection. It may last 3–8 weeks.

These coughs typically clear up on their own. However, treatments and home care techniques can help.

In some cases, an underlying health issue causes a chronic cough that may resemble a postviral cough. Viral infections can exacerbate the issue.

Seek medical advice if a cough lasts longer than 8 weeks, if the cause of a cough is unclear, or if a persistent cough is causing concern.