Written by: Cameron Rosario
Medically reviewed by: Rob Philibert MD PhD
Although 80% of patients with COVID will experience mild symptoms that can be resolved in a few weeks, the remaining 20% will potentially experience continuing symptoms that can remain for weeks to months. This extended period of illness is known as long-haul COVID. According to the American Medical Association, long-haul COVID includes over 100 different potential signs and symptoms. However, this may be just the beginning with researchers expecting that more symptoms will be recognized as studies progress.
Demographic factors affect the rate of illness. Gender has a prominent role in its manifestation. While approximately 70-80% of individuals experiencing severe acute infections are men, women make up 70-80% of those experiencing long-haul COVID. Age may also affect long-haul; most patients are around the age of 40.
WHAT DO WE KNOW ABOUT LONG-HAUL COVID?
The symptoms of long-haul COVID can last for weeks to months and include shortness of breath, a racing heartbeat, nausea, diarrhea and intermittent spiking fevers. These chronic health manifestations can be debilitating. However, because the syndrome is new, the duration and severity of long-haul COVID remain to be a subject of investigation for many scientists. “From my perspective, it appears that post-COVID symptoms tend to be more common, severe, and longer-lasting than other viral illnesses, such as influenza,” says Timothy Hendrich, a viral immunologist and infectious disease expert at the University of California, San Francisco.
Aside from the common physical symptoms, experts have also been carefully monitoring the mental health outcomes. The short-term effects on the brain which include confusion and stroke are beginning to be well described. In contrast, the long-term psychological effects of COVID, including anxiety, hopelessness, depression and PTSD, following acute infections are still being understood. Factors influencing the prevalence and severity of COVID-associated mental health outcomes are an area of intense study.
LONG-HAUL COVID CARDIOVASCULAR EFFECTS
COVID causes damage to the heart by both direct and indirect mechanisms. The direct effects are the easiest to understand. The cells in the heart express angiotensin-converting enzyme-2 (ACE-2) receptors to which the coronavirus attaches before entering cells. This vulnerability conferred by ACE-2 receptor expression has consequences. Professor Sir Nilesh Samani, the medical director at the British Heart Foundation notes that while “this virus may be a respiratory infection, however, the most common underlying health conditions in those who die are cardiovascular.” In severe cases, this infection by COVID can give rise to myocarditis – the inflammation of the heart muscle. In addition, because arterial endothelial cells also express high levels of the ACE-2 receptor, COVID can also cause inflammation within the lining of the blood vessels of the cardiovascular system. This inflammation can lead to an increase in the formation of blood clots and an increased risk for heart attack and strokes.
The indirect effects of COVID infection on the heart are less well understood. Some scientists hypothesize that a chronic lingering infection by COVID may be producing additional damage to the heart. Unfortunately, because we do not yet have a good method through which to measure lingering COVID infections in the cardiovascular systems of living individuals, much of this conjecture is highly speculative. However, the effect of COVID on the ability of individuals to exercise and attend preventative care visits is much more quantifiable. Some researchers speculate that these and other secondary effects of the global pandemic on healthy living behaviors may be greater than those of the acute infection.
CONTINUING STUDIES GENERATE AN IMPROVED UNDERSTANDING
One thing that is certain is that there is a need for continuing study. Recently, a study published in the Journal of Clinical Microbiology and Infection, investigated the prevalence of continuing symptoms in adults that experienced mild to moderate COVID cases. Within the 150 participants, two thirds were experiencing symptoms including a shortness of breath, loss of smell and taste, and fatigue during the two-month follow up. Additionally, researchers from King’s College (London) evaluated approximately four million individuals in the United Kingdom regarding their ongoing symptoms using a phone app. By gathering this information, it was found that 10 percent of patients have persistent symptoms after a one month follow up and persisted to three months in 1.2 to 2 percent.
Studies of COVID in animals, such as mice and ferrets, are also important. In particular, they are being used to develop and test models to explain the continuation of symptoms experienced by COVID long haulers. For example, Terina Martinez, a field application scientist at Taconic Biosciences, has been working on generating mouse models using modern gene editing and gene targeting that address long-haul COVID. But the results of these studies are not always easy to interpret since immune responses to COVID may vary as a function of an individual’s unique genetic and environmental factors. Nadia Rosenthal, Scientific Director of the Jackson Laboratory (JAX), summed up these challenges by stating that “you can’t use one inbred mouse to represent the entire human race” due to these external factors.
HOW CAN YOU TAKE ACTION?
Medical community progress
With rising awareness of long-haul COVID, medical communities have been providing a multidisciplinary and integrated approach through a network of long-haul COVID specialist clinics.
Get the shot!
If you have not already, consider looking online for clinics or centers that are administering COVID vaccines in your community. Receiving the vaccine is a safe and effective way to enable your body to build protection against the virus and the potential long-term effects.
Continue exercise safely
Maintaining a healthy lifestyle is never a bad idea, even after recovery. To exercise safely, more compromised individuals should be following a more personalized workout plan in contrast to individuals who are more immune and can visit their gym.
Continue routine CVD monitoring
Continuously monitoring your cardiovascular health is a must, even for those without severe cardiovascular problems. COVID will likely be with us for an extended period of time. Stay on top of your heart health to minimize the likelihood of any possible complications.
- Marx, V. (2021). Scientist set out to connect the dots on long COVID. Nature, 18, 449-453. http://doi.org/10.1038/s41592-021-01145-z