A sense of optimism is growing around society’s recovery from the COVID‑19 pandemic, draped against a background of effective vaccine development and its widespread rollout. While clinicians have a better understanding of COVID‑19 disease, science is still struggling to make sense of its long-lasting symptoms, known as Long COVID, and what “long haulers” have in common.

The problem is that much may be known about who is at risk for acute COVID‑19 disease, but little is known about the prevalence, risk factors, natural history, and etiology of Long COVID.

There is no distinct pattern of who gets Long COVID; it is reported in individuals who have mild to severe illnesses, and it can involve multiple organ systems. Additionally, it’s not clear if the symptoms represent a new syndrome unique to COVID‑19, as some sequelae overlap with recovery from similar illnesses, such as post-intensive care syndrome and multisystem inflammatory disorder. Some individuals with Long COVID report new symptoms that were not present in their acute illness, or symptoms that seemed to resolve but reappeared.

There is also no widely accepted definition of the stages of COVID‑19 recovery. For example, the U.S. CDC defines late sequelae of COVID‑19 as those extending beyond four weeks after initial infection. These long-term effects have recently been renamed PASC or post-acute sequelae of COVID‑19. In comparison, ongoing symptomatic COVID‑19 has been defined as symptoms extending from 4 to 12 weeks after onset and post COVID‑19 as symptoms that develop during or after COVID‑19 and continue for 12 weeks or more.

Long-Haulers’ Symptoms

Long COVID symptoms are numerous and varied, and no two people are affected the same way. Common symptoms include fatigue, shortness of breath, cough, joint pain, and chest pain. Other commonly reported symptoms include depression, muscle pain, headache, and intermittent fever.

Less common serious long-term complications include:

• Cardiovascular - Inflammation of the heart muscle, ventricular dysfunction
• Respiratory - Pulmonary function abnormalities and abnormal chest imaging
• Renal - Acute kidney injury
• Endocrine - New-onset diabetes (mechanism undefined)
• Dermatologic - Rash, hair loss
• Neurological - Smell and taste problems, sleep issues, difficulty concentrating, memory problems
• Musculoskeletal - Symptoms similar to myalgic encephalomyelitis/chronic fatigue syndrome (brain fog, severe persistent fatigue, poor concentration)
• Psychiatric - Depression, anxiety, mood changes

Long COVID Incidence

A few studies, however, have given us a reading on incidence rates. Self-reported data, submitted through the UK’s COVID Symptom Study App from 4,182 incident cases, suggests one in seven have symptoms for more than four weeks, while one in 20 have symptoms for more than eight weeks.¹

In the U.S., the CDC conducted a phone survey in July 2020 to study symptom duration and risk factors for delayed return to usual health on a sample of 292 adults who tested positive for SARS‑CoV‑2. The results showed that 35% of these respondents reported not having returned to their usual state of health 14‑21 days after a positive test. For comparison, 90% of people with influenza recover within this timeframe.² Patients aged 50 or above and the presence of three-plus chronic medical conditions were associated with not returning to usual health within 14‑21 days.

In a recent study of outpatients by the University of Washington, around 30% with COVID‑19 reported persistent symptoms three to nine months after illness onset; 14% reported fatigue and 30% reported decreased health-related quality of life.³

In China, a large cohort study of about 1,700 hospitalized patients with confirmed COVID‑19 showed that at six months, 76% of patients had at least one residual symptom.⁴ More severely ill patients had an increased risk of pulmonary diffusion abnormality, abnormal lung CT scan at follow-up, fatigue or muscle weakness, and anxiety or depression.

It appears that COVID‑19 can result in prolonged illness even in individuals who have a milder case.

Underwriting Assessment Advice

With new data accumulating all the time, it’s perhaps too early to draw firm underwriting conclusions about Long COVID. That being said, the residual symptoms of COVID‑19 do represent a growing body of research with many parallels to the sequelae of other coronavirus diseases such as SARS and MERS.

For prognostication from an underwriting point of view, until long-term follow‑up studies become available, the risk of an individual with Long COVID should be carefully assessed based on present complaints and compared with similar medical diseases.

Symptoms should be classified by specific product and in relation to the global risk assessment.

Finally, bear in mind two findings unique to patients with COVID‑19. First, those who appear to be at highest risk for acute COVID‑19 disease do not necessarily appear to be the same individuals who are at risk for Long COVID. And, those with prolonged symptoms can include individuals who don’t require lengthy hospitalization and initially had mild to moderate symptoms.

For a deeper discussion or specific question you have about Long COVID, don’t hesitate to give me a call.

Endnotes

1. https://www.medrxiv.org/content/10.1101/2020.10.19.20214494v2
2. https://www.cdc.gov/mmwr/volumes/69/wr/mm6930e1.htm
3. https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2776560
4. https://www.sciencedirect.com/science/article/pii/S0140673620326568
5. https://jamanetwork.com/journals/jama/fullarticle/2762130