What we know (so far) about long Covid

September 25, 2022

For most people who catch Covid, their symptoms typically fade within two weeks. But for others who suffer from a phenomenon called long Covid, their symptoms can persist for months or years even after testing negative. Symptoms can also reappear long into one’s supposed recovery. Researchers have grappled with this concept of long Covid for a while now. Because it can arise from both mild and severe Covid cases and is associated with over 200 symptoms which vary in severity, it cannot be easily defined or diagnosed; even the World Health Organization’s clinical case definition for long Covid has been scrutinized by scientists and researchers alike. However, in the last month, numerous studies have made strides in demystifying aspects of this troubling phenomenon.

Common long Covid symptoms include shortness of breath, fatigue, and a lingering cough, but some studies have recently uncovered even more. An analysis of primary care records of England residents—some with prior Covid diagnoses and others with no prior history of the virus—revealed hair loss and reduced sex drive to be two novel symptoms of this syndrome. These symptoms were analyzed 12 weeks after initial infection.

From the analysis, researchers were also able to categorize symptoms into three groups: varied (ranging from fatigue to pain), cognitive ( brain fog, insomnia, and depression), and respiratory symptoms (cough, shortness of breath, wheezing). The majority of long-Covid sufferers experienced a wide variety of symptoms, with 80% falling into the first category. 15% experienced persistent cognitive symptoms, and 5% experienced respiratory symptoms.

Importantly, researchers noted that because their findings were based solely off of GP consultations and what symptoms participants reported to their doctors, this limited the possible range of their analysis. They could only compare the presence and severity of the reported symptoms in those with and without a prior history of Covid.

“About 5 to 10% of people may take a long time to recover their senses of taste and smell.”
– Dr. Gary Desir

Nevertheless, this analysis provided further support to the fact that long Covid may not look the same for everyone. There is an extensive range of symptoms, which highlights the need for “tailored health services” and clinical trials to test appropriate, varied treatment options.

Another study from The BMJ looked specifically at loss of taste and smell—a relatively common symptom among earlier strains of the virus—and found that it affects approximately 5% of long-Covid sufferers. Researchers synthesized medical data from 18 previous studies and, with the help of mathematical modeling, found that 5.6% of those with a previous Covid infection experienced loss of smell, and 4.4% experienced loss of taste after 180 days. However, the data also suggested that these statistics underestimated the actual number of people who would experience such changes to their olfactory and gustatory senses. Dr. Gary Desir, professor of medicine and chair of internal medicine at Yale School of Medicine, stated that “about 5 to 10% of people may take a long time to recover their senses of taste and smell.” While this may not initially seem like a large number, this would mean that a whopping 4.5 million people are potentially susceptible to long-term changes to their sense of smell and taste in the US. Dr. Christopher von Barfield, co-author of the study and professor of physiology and cell biology at the University of Nevada Reno, hopes that studies like these will kickstart new research into improved therapy and treatment options.

On a federal level, on August 3rd, the Biden-Harris administration released a National Research Action Plan on Long COVID. This report called for the formation of an Office of Long COVID Research and Practice, as well as “proposes an effective, comprehensive, and equitable research strategy to inform [the] national response” to the syndrome. The administration also released a comprehensive report which delineates the federal resources available to long-Covid sufferers and advises healthcare workers on how to best tend to their patients.

There is still much we do not know about long Covid, but these studies and federal reports show that research on this phenomenon is only growing. Indeed, we will not be left in the dark forever, and can look forward to even more streamlined, government-driven research endeavors in the future.