Post-COVID-19 syndrome: What experts know so far

It is becoming clear that in addition to the immediate clinical effects of SARS-CoV-2, the novel coronavirus can have long-term manifestations, experts said.

These symptoms, according to Allison Navis, MD, assistant professor in the division of neuro-infectious diseases and the director of the neurology clinic at Icahn School of Medicine at Mount Sinai, are known as post-COVID-19 syndrome, long COVID-19 or long-haul COVID-19.

“In general, we’re using this to describe the persistence of symptoms in patients who had COVID-19 infection,” Navis said during a press briefing held by the Infectious Disease Society of America.

She said these symptoms persist “usually at least 4 weeks after a COVID-19 infection has resolved, but for many people, these symptoms last much longer — at least 2 to 6 months.”

“We’ve seen many people who have had symptoms for close to a year now,” she added.

Navis and Kathleen Bell, MD, Kimberly Clark Distinguished Chair in Mobility Research and a professor and chair of the department of physical medicine and rehabilitation at UT Southwestern Medical Center, spoke during the briefing about their experiences with persistent COVID-19 symptoms.

‘Long-haul’ COVID-19

Navis said that for many patients, long-term COVID-19 symptoms are similar to those they experienced during their infection, but some patients may experience new symptoms.

She added that post-COVID-19 syndrome has “a large constellation of symptoms,” and that while there are limited studies on the exact prevalence of each symptom, fatigue appears to be the most common. It may be caused by cardiac or pulmonary issues in some patients; however, the cause is unclear in others.

After fatigue, Navis said, shortness of breath and other pulmonary symptoms are the most common. Cardiac issues, she added, are also common among patients with post-COVID-19 syndrome.

In addition, there are reports of neurological symptoms, such as cognitive changes, or “brain fog,” headaches paresthesia and dysautonomia, according to Navis.

Other long-term COVID-19 symptoms reported by patients, she said, include light-headedness or dizziness, palpitations, gastrointestinal disturbances, joint pain, rash, persistent anosmia and a variety of other symptoms.

Navis noted that the cause of many of these symptoms is unknown, but it is a major focus of current research.

“There’s a question of whether this is something unique of the virus itself, and that the virus is triggering these symptoms, or if this could be part of a general post-viral syndrome,” she said.

Navis added that these types of symptoms had been seen following other viruses, and that other post-viral syndromes have appeared to last for a year or longer, but then “resolve on their own.”

“I think there’s a question of whether this is a general post-viral syndrome, and we just haven’t had a global pandemic on this scale from one virus before,” she said. “The number of patients that we’re seeing coming in with post-COVID-19 syndrome could just be due to the sheer number of the people infected with COVID-19 virus.”

Long-term COVID-19 vs. other issues

Bell noted that when evaluating patients who appear to have post-COVID-19 syndrome, as with any patient who experienced a major medical event or trauma, there are three aspects to consider: the patient, as a whole, before the event; the event itself; and the experience after the event.

She said many patients with COVID-19 also had hypertension, diabetes, obesity and other infections that may predispose them to severe infection and issues later in life. For instance, Bell said, patients with prolonged hypertension may have chronic microvascular disease in their brain, which may lead to brain issues later in life.

“People may find that they may have been compensating very well for problems they had beforehand — maybe some minor cognitive impairment that they had from the hypertension or the microvascular disease,” Bell said. “So, when you put a trauma like this and a stress from the body, it may bleed over into actually becoming symptomatic for them.”

The disease itself, she said, “can cause all sorts of problems with inflammatory responses in the brain and around the heart, around the nerves, around the muscles, et cetera.”

Additionally, treatment during the disease may affect long-term health outcomes. For instance, Bell said that patients treated in the ICU may have been moved into a prone position, which places pressure on nerves that are typically not under pressure. This may cause some patients — particularly those with diabetes — to develop peripheral neuropathy.

Then after experiencing the disease or trauma, she said patients experience their own mental health reactions and their family’s reaction.

For example, she said that patients who were hospitalized for long periods of time have demonstrated signs of PTSD, anxiety and depression as a reaction to their experience. Additionally, having family or friends be nervous or afraid of patients after they recover from COVID-19 infection may contribute to these issues.

She added that all these factors combined are “plumping out the picture of the disease itself.”

Which patients experience post-COVID-19 syndrome?

Bell said that it is uncommon for patients with “completely” asymptomatic disease to develop post-COVID-19 syndrome.

“We certainly are seeing people who were never hospitalized, however, come in with persisting symptoms,” she said.

Navis added that she has seen “maybe one or two” patients who had asymptomatic COVID-19 and later presented with mild post-COVID-19 symptoms, but most patients with long-term symptoms previously had symptomatic disease.

“The majority of my patients had what we would call mild COVID-19, meaning they weren’t hospitalized, but they might have been sick at home for several weeks and felt quite ill,” she said. “That does seem to encompass the majority of the patients that I’m seeing.”

When asked whether patients with COVID-19 who also have preexisting conditions are more likely to experience post-COVID-19 syndrome, Bell and Navis both said that more research is needed.

While conditions like diabetes, hypertension, lung disease and obesity all indicate more severe COVID-19 infection, Bell said, “we all know that we’ve seen young people, perfectly healthy young people, that have had very difficult courses with this disease.”

She added that large, multicenter prospective studies are needed to understand the effect of preexisting conditions on the risk for post-COVID-19 syndrome.

Navis agreed, adding there are some cross-sectional studies that discuss post-COVID-19 syndrome, but larger studies are needed.

“Anecdotally speaking, for me, again, a lot of my patients were pretty healthy,” she said. “I do have a lot of patients who had no prior medical issues, or maybe mild issues, but we really don’t know.”