Long Covid is Common After Mild Covid-19 Infection

“I was vaccinated but developed a Covid infection shortly before being eligible for a booster shot. I had a fever and fatigue which lasted for about a week. Labeled by the doctor as “mild,” I felt awful and would not wish it on anyone. But because of persistent fatigue, I had to take a leave of absence from my work as an accountant for nearly 3 months. The fatigue was intense and with it came brain fog. I just couldn’t do any serious thinking; certainly nothing with numbers. Even now, eight months later, I still am not fully recovered. The most frustrating aspect at the beginning was my doctor not paying attention, not believing that I felt as lousy as I did, and not appreciating the depth of my incapacity.”

Long Covid occurs after a mild infection, is very real, is common, and can be quite debilitating as the story of my friend, Arthur, above demonstrates. Even after a very mild disease, individuals can have many symptoms often lasting weeks to months or even over a year. The causes, other than the association with Covid-19, are usually unclear and as a result, the treatment is ad hoc.

Patients frequently called themselves “Long Haulers,” physicians tend to use the term “Long Covid,” and the National Institutes of Health, being more specific, uses the term “Post-acute Sequelae of Covid-19” or PASC.

Long Covid was first thought to be uncommon. Doctors were initially confused, being not certain that it was actually related to the prior infection and thinking perhaps the strange symptoms were just psychosomatic. In actuality, it’s a very real phenomenon; it is quite common even after mild Covid-19; and has varying presentations, making it all the more confusing.

Who gets it? It occurs after mild to moderate infection and may well occur among people who have asymptomatic infection. This is quite different than the person who has been hospitalized and in the ICU with severe Covid-19. These individuals tend to have widespread damage in their lungs, heart, kidneys, blood vessels, and other organs and so it may stand to reason that they have persisting symptoms after discharge from the hospital. They too can develop new Long Covid symptoms but in this article and the ones to follow, the emphasis will be on those with mild infections.

How long do these syndromes last? The answer is unclear but it certainly can persist for months and they can range from a mildly annoying to literal incapacitation.

What are the symptoms? They are protean and include fatigue, “brain fog,” other cognitive difficulties, shortness of breath, sleep disorders, fevers, anxiety and depression, a persistent loss of taste and smell or headaches. Some symptoms that were initially thought to be very uncommon include tremors which now appear to occur in about 40% of affected people and a sense of vibrations in about 30%. Some develop symptoms of circulatory imbalances and various cardiovascular dysfunctions (See my following article.)

Emotional health has been affected among Long Covid sufferers with increases in anxiety, increased frequency of depression, and many sleep disturbances. In many individuals, perhaps especially in older people, there is mild but real brain damage. This causes pervasive yet subtle cognitive, behavioral and psychological problems.

What is most common? Chronic fatigue is perhaps the most common symptom. Its degree varies from person to person but certainly can be truly debilitating. Individuals report feeling “rundown” and tired. They find they can’t exercise or do even simple tasks without feeling truly exhausted. This can persist for weeks, months or over a year.

What exacerbates symptoms? Some people have symptoms that get worse after physical or even mental exertion. This was initially unrecognized as related to Long Covid but now it’s appreciated to be common and is termed “post-exertional malaise.”

Do individuals with Long Covid have the same symptoms as they did with their initial infection? Not necessarily. Symptoms can be a continuation of the original ones but often are entirely different or can be some combination. Symptoms don’t necessarily persist unchanged. They can wax and wane, disappear and reappear. Patients can feel better for a while and then relapse with symptoms and this can be repeated ad infinitum.

Who is at risk? Just about anyone but women seem to be a bit more affected than men, as are older than younger adults, as are those with more symptoms at the time of initial infection. One study suggests that those with an unhealthy microbiome, meaning a loss of bacterial diversity in the GI tract, compared to the typical healthy microbiology, adds to the risk of developing Long Covid.

Another report suggested those more likely to develop Long Covid had a lower level of immunoglobulins in the blood tested after initial infection but before Long Covid developed, those with low levels of autoimmune antibodies (low enough not to have caused an autoimmune disease,) those with Coronavirus particles in the bloodstream, or those with reactivation of the Epstein-Barr virus. Just what all of this means is unclear and it is important to remember that these are all correlations and correlation does not necessarily equal causation.

How frequent is Long Covid? The answer is unclear but certainly, 10 to 30% of people with mild Covid develop Long Covid, quite possibly it’s more. It’s suspected that those with asymptomatic Covid-19 can also develop Long Covid.

What about kids? It’s probably less common among children, perhaps 4 to 10% but one report found a much higher incidence. Whatever the incidence, it is stressful, to say the least, for the child who is affected.

Does vaccination prevent Long Covid? Unvaccinated people have the highest incidence of Long Covid. Those who are vaccinated and get a breakthrough infection can definitely develop Long Covid although the incidence is lower. Those who are vaccinated and boosted and then get a breakthrough infection have the lowest incidence. But for the individual who develops Long Covid, it’s a problem of significance no matter their vaccination status as Arthur found with his fatigue and brain fog syndromes.

How long does Long Covid last? It can vary extensively — from weeks to months to over a year. In one international survey of some 3762 participants with Long Covid, 91% had symptoms that persisted for greater than 35 weeks (seven months, the length of observation.) Among these individuals, 86% had relapses that were triggered by physical exercise, mental exercise or just stress. At the time of the survey, 46% required a reduced workload compared to their pre-infection employment status. Twenty-three percent had not worked since developing Long Covid. The survey concluded that “by seven months, many had not yet recovered, had not returned to previous levels of work, and continued to experience significant symptom burden.”

Bottom line — Just one more reason why you want to avoid becoming infected. And it definitely tells us that getting infected to build immunity is not at all-wise.

In the next article in this multi-part series, I will do a deep dive into Long Covid heart damage following mild Covid. Please join me.

Stephen C Schimpff, MD, MACP, is a quasi-retired internist, professor of medicine, former CEO of the University of Maryland Medical Center, and author of Longevity Decoded — The 7 Keys to Healthy Aging and his co-authored book with Dr. Harry Oken BOOM — Boost Our Own Metabolism.