Most people who get the flu, pneumonia or even COVID are looking at feeling bad for a week or two. As the virus subsides, symptoms start to lessen, and they begin to feel better. Soon, they’re back to feeling as good as they did before they got sick.
But in some cases, it doesn’t work like that. The virus may linger longer in the body. Or something about the body’s response to the virus may trigger new, ongoing symptoms. These after-illness illnesses are known as post-viral syndromes.
What are post-viral syndromes?
“This phenomenon of post-viral syndromes was first documented after the Spanish flu (in 1918-1920),” says Nisha Viswanathan, MD, director of the Long COVID Program at UCLA Health. “It was an extremely virulent strain of flu, and after that virus some people experienced lasting symptoms such as tremors, brain fog and cognitive changes.”
Post-viral syndromes involve symptoms that occur weeks or even months after you’ve recovered from a viral infection. But exactly how and why they happen in some cases (and not others) is still something of a medical mystery.
“There is a long history of post-viral illnesses, but there has not been nearly enough research on them,” says Dr. Viswanathan. “Are they all being caused by the same thing? We don’t really know.”
What are the symptoms of post-viral syndromes?
The most common feature of any post-viral illness is fatigue. And it’s not just that you feel a little rundown and extra tired.
“Post-viral fatigue is disabling,” says Dr. Viswanathan. “People with these conditions are so tired they can’t function – it’s difficult to work or to spend time socializing with friends and family.”
Long COVID often causes erratic heartbeat and exercise intolerance, as well. It’s also not uncommon for people with post-viral syndromes to experience cognitive symptoms, including brain fog and mood issues.
“When you go from a high-functioning busy person to being disabled by a chronic illness, it can be very hard on your mental health,” says Dr. Viswanathan.
Is long COVID a post-viral syndrome?
In theory, any viral infection could trigger a post-viral illness. But the most common viruses to cause them include:
- COVID
- Epstein-Barr virus
- Flu
- Herpes
- Pneumonia
Until the COVID pandemic, chronic fatigue syndrome was the most commonly known type of post-viral syndrome. Although the exact cause of chronic fatigue syndrome is still unknown, it is often linked to a previous infection — such as Epstein-Barr virus. Now, long COVID is the post-viral syndrome getting the most attention.
When to see the doctor about post-viral syndrome
“We know that at least 9% of people who’ve had COVID are struggling with long COVID,” says Dr. Viswanathan. “That’s many millions of people.” Millions more are dealing with post-viral fatigue left behind by a different illness.
Certain risk factors make it more likely to acquire long COVID and other post-viral syndromes. These include:
- Assigned female at birth
- Diabetes
- High blood pressure
- Prior autoimmune disease or being immunocompromised
If, in the weeks or months after a viral illness such as flu or COVID, you experience symptoms such as extreme fatigue and brain fog, you should see your doctor. While there aren’t currently any cures for post-viral illnesses, there are treatments that can help ease symptoms.
Self-care for people with post-viral syndromes
Adjusting — both physically and mentally — to life with a post-viral syndrome can be challenging. “The first step is to build a sense of acceptance around what is your new normal,” says Dr. Viswanathan. “Accepting where you are and what you’re capable of helps you feel less stressed and helps with the healing process.”
She suggests keeping a journal that helps you track your fatigue and other symptoms. This allows you to see what triggers symptoms and how you can better pace yourself.
“About 75% of people will have some degree of complete recovery,” says Dr. Viswanathan.
And if you’re not finding the answers and help you need during your illness, she recommends looking for a doctor who better understands post-viral illness.
“Find someone who can help and support you,” she says. “And give yourself grace as you work toward healing.”
