Post-viral syndrome refers to a sense of tiredness and weakness that lingers after a person has recovered from a viral infection, such as the flu. Doctors may also refer to post-viral syndrome as “post-viral fatigue.”

People may experience post-viral symptoms, such as fatigue, for weeks or months after an infection. Some treatments and home remedies may relieve fatigue and help people manage their energy levels.

Post-viral syndrome may appear similar to other health issues, but it is important to work with a doctor to resolve it if the symptoms last too long.

This article provides an overview of post-viral syndrome, including its causes and symptoms. It also explains how to treat it and when to contact a doctor.

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As the name suggests, post-viral syndrome typically occurs after a person experiences the effects of a virus. It can develop even after seemingly simple bouts of the flu or the common cold.

Once the person’s body has removed the virus, post-viral syndrome may make them feel drained of energy and generally unwell. This feeling may linger for days to months after a viral infection.

The trigger for post-viral syndrome appears to be a reaction to the virus itself. Many doctors will treat post-viral syndrome in the same way as they treat chronic fatigue syndrome (CFS), as the two can have a similar presentation.

However, while CFS causes symptoms for no apparent reason, the symptoms of post-viral syndrome appear to have their origins in the infection.

The medical community is not sure why the symptoms arise. Some experts believe it may be due to the lingering effects of the virus as the body continues to clear it out.

A 2018 study notes that another theory is the virus overloads the immune system, causing a reaction that triggers symptoms similar to those of CFS.

The authors of an earlier study suggest that the symptom of fatigue after a viral infection is due to inflammation in the brain.

Viruses cause the immune system to respond and attack them. This response causes stress and inflammation in the body. The effects of this response often leave people feeling down, fatigued, and sometimes depressed.

Almost any viral infection can trigger post-viral syndrome, including:

Post-viral syndrome may be more prevalent or apparent in people with weakened immune systems.

The symptoms of post-viral syndrome may vary from person to person, but most people describe feeling fatigued and generally unwell. This feeling persists no matter how many hours of sleep the person gets or how well they take care of themselves.

Post-viral syndrome may cause additional symptoms, such as:

In some cases, it may be that the body is simply taking extra time to clear the virus completely. However, if symptoms such as these linger for longer than a few weeks, a person should talk with a doctor.

As members of the medical community have different opinions on post-viral fatigue, it can be difficult for them to agree on how to treat it, and recommendations will differ.

In some cases, the person will require no treatment, and managing the symptoms until they feel better will be enough.

To this end, doctors may recommend taking vitamins, eating a nutritious diet and keeping with other healthy lifestyle practices along with some simple symptom management tools, such as over-the-counter pain relievers to treat headaches or other general aches and pains.

Some lifestyle tips may help support the body as it works through post-viral syndrome and may help reduce recovery time. These include:

  • sleeping 7–9 hours each night
  • taking naps throughout the day as necessary
  • conserving energy and getting plenty of rest
  • drinking plenty of water
  • engaging in mild exercise during the day
  • eating a healthy, balanced diet that contains plenty of fresh fruits and vegetables and anti-inflammatory foods
  • avoiding heavy, greasy foods, such as fried or fast foods

Some people may also feel more rested after trying stress reduction techniques.

The American Myalgic Encephalomyelitis and Chronic Fatigue Syndrome Society notes that almost 50% of people with myalgic encephalomyelitis (ME) and CFS — both of which can cause symptoms similar to those of post-viral syndrome — use alternative therapies, such as meditation, yoga, and acupuncture, to help them cope.

Getting a massage may also help some people relax and deal with muscle pain.

The recovery time for people with post-viral syndrome can vary widely. A 2017 study noted that recovery time appears to be better the more quickly a person receives their diagnosis.

Post-viral syndrome is temporary. Although the effects may linger, many people can expect their symptoms to resolve within a few weeks.

In some cases, symptoms may last for longer, even up to several months.

A smaller, older study reported that 31% of people experienced prolonged fatigue of longer than 6 months following treatment for West Nile virus. The average duration of this symptom among these individuals was 5 years.

After a time, doctors may diagnose a person with a separate disorder, such as CFS. They will then order any necessary treatments and possibly give the individual some additional tips on how to manage their symptoms.

Recovering from a viral infection can drain the body. Yet, even after the body clears the virus, the symptoms, including fatigue, may linger.

The medical community is not sure exactly what causes post-viral syndrome. Some people believe it is a condition in its own right, whereas others think the virus may have triggered another condition, such as CFS or depression.

Some people with post-viral syndrome — often those who receive an early diagnosis — may get better in a few weeks. However, some cases may last a few months, and doctors may offer other treatment options for people who experience symptoms for a longer period.

Anyone experiencing symptoms for more than a few weeks after recovering from the virus should contact a doctor for a diagnosis.