Long COVID: Symptoms and Treatment — What Do We Actually Know?

The World Health Organization defines post-COVID-19 condition (commonly called long COVID) as a set of symptoms occurring in people with a confirmed or probable past SARS-CoV-2 infection, usually present around 3 months from the onset of illness, persisting for at least 2 months, and not explained by an alternative diagnosis. This is deliberately a broad, functional definition — not one specific symptom, just a time frame and a criterion of excluding other causes, which reflects how heterogeneous this clinical picture is.

This heterogeneity is one of the main reasons long COVID remains difficult to study and treat: different patients present very different combinations of symptoms, with different likely mechanisms, under one shared diagnostic label. This situation resembles other symptom clusters with unclear, multifactorial pathophysiology, where simply naming the problem doesn't yet mean understanding its mechanism or having one universal therapy.

More than 200 different symptoms have been linked to long COVID, but a few of them dominate in most observational studies. Chronic fatigue is reported most often, frequently described as qualitatively different from ordinary tiredness — disproportionate to exertion and worsening after physical or mental activity (so-called post-exertional malaise). "Brain fog" — subjective difficulties with concentration, information processing, short-term memory, and executive function — is the second most commonly reported problem and can be especially frustrating, since it doesn't always correlate with results on standard neuropsychological tests.

The mechanism of long COVID isn't yet fully explained and is most likely heterogeneous — different subgroups of patients may have different dominant pathophysiology under a shared clinical label. Hypotheses under investigation include: persistent reservoirs of the virus or its fragments in tissues outside the respiratory system, chronic immune system dysregulation and low-grade inflammation persisting after the acute infection resolves, microcirculation disturbances and microclot formation, reactivation of latent viruses (e.g., Epstein-Barr virus), and autonomic nervous system dysfunction.

A key, honest piece of information: currently there is no single drug approved specifically for treating long COVID as a distinct condition. Management focuses on relieving the specific symptoms dominant in a given patient and on functional rehabilitation, rather than on one universal causal therapy.

There is no single blood test confirming long COVID. Diagnosis is primarily one of exclusion — the doctor checks whether the reported symptoms (fatigue, breathlessness, heart palpitations) don't have another, identifiable and treatable cause, such as hypothyroidism, anemia, heart or lung disease, anxiety-depressive disorders, or sleep apnea. Only after reasonably excluding these alternatives, and if the time criteria are met, is post-COVID-19 condition diagnosed.

Depending on the dominant symptoms, the doctor may order additional tests — a blood count, inflammatory markers, thyroid function tests, an echocardiogram, or spirometry — not to "confirm" long COVID directly, but to rule out specific, treatable alternatives and assess the severity of individual symptoms, which matters for further rehabilitation management.

Long COVID is a real clinical problem, well documented in the literature, not a "fabrication" or purely an anxiety symptom, as it was sometimes dismissed in the early years of the pandemic. At the same time, honesty toward patients requires admitting that science still doesn't have one mechanism or one therapy — which means management must be individualized, based on the dominant symptoms of a specific person, not on one universal protocol.

If you suspect you have long COVID, the most practical first step is a consultation with a doctor to rule out other, treatable causes of the symptoms — and only then, with a confirmed diagnosis, implementing individualized rehabilitation, ideally under the care of a specialist familiar with the pacing strategy, rather than experimenting on your own with intensive training or costly, unverified supplements.