Persistent covid creates a mosaic of unknowns that requires immediate action. While we have learned a lot about this disease in the last two years – about its causes, incidence, biomarkers that alert us to its presence, and potential treatments – there are still many issues to be resolved.

1. How many people suffer from it?

Symptoms may return weeks or months after infection with SARS-CoV-2; or perhaps they were never lost and were not weakened or aggravated. Some people have long-term heart, kidney, liver, or nerve problems after the illness has subsided. This release of pathologies without a specific treatment causes us to face a real problem called persistent covid.

The thing is, we don’t know its exact prevalence because the wide variety of symptoms overlaps with many other conditions. Also, there are no definitive or qualitative diagnostic tests.

In one of the first published meta-analyses, our team compiled the top 50 symptoms of long-term COVID patients recorded in 2020. 8 out of 10 infected adults had at least one of these symptoms months later. A more recent study in the Netherlands shows that 1 in 8 people develop the condition compared to control groups.

It should be noted that we are talking about two types of patients. If those affected had a serious infection and were hospitalized, about half of the cases showed persistent covid. The second group includes people with mild or asymptomatic infections who develop symptoms within three months of infection.

The list of ailments included chronic fatigue, chest pain, shortness of breath, muscle pain, headaches, and a wide variety of neurological symptoms. In total, more than 200 symptoms have been associated with persistent covid, and certain factors such as vaccination or the type of SARS-CoV-2 variant that caused the infection can determine its effect.

For example, the prevalence of long-term disease in persons infected with the omicron subvariable BA.5 and previously vaccinated with booster doses is still unknown. Either way, the intensity and duration of your symptoms will likely be insignificant.

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2. Why does it occur?

The source of the symptom puzzle that characterizes persistent covid can range from deregulation of the immune system to changes in the autonomic nervous system that cause immune dysfunction or dysautonomia; that is, involuntary changes in physiological functions: pulse, breathing and body temperature. It can cause dizziness, fatigue, fainting, and other problems.

Some hypotheses point to a chronic inflammation triggered by an exaggerated immune system response after infection, which is prolonged by virus reservoirs that the body cannot completely eliminate. dir-dir excessive movement It can also cause blood clots.

Another theory focuses on autoimmunity and the effect of autoantibodies produced after infection—antibodies that attack our tissues. Perhaps both causes coexist, and there are many more, making it difficult to find a single treatment that covers all targets.

Studies are also needed to evaluate other factors, such as disease-associated variants, symptoms the patient experienced before infection and worsening, the severity of the vaccine, and whether the control groups in the trials were appropriate.

3. Can a correct diagnosis be made?

Although the persistent presence of covid is widely known, the criteria for declaring it vary, and different medical authorities accept varying symptoms and levels of severity. It is very important to find a profile that can define the disease and guide treatments in order to confirm the diagnosis as soon as possible.

Normally, clinical diagnoses are based on blood tests that attempt to create an individualized pathological profile. In any case, one requirement is proof of passing covid in the clinical history. Unfortunately, institutions leave the responsibility of proving this to patients for access to medical or social services.

But not everything has to depend on the initial infection test. A recent study has identified objective measurement patterns that allow persistent covid to be diagnosed with 94% accuracy. Indicators include herpes virus reactivation and the presence of various antibodies, autoantibodies, and cellular and immune markers.

Cortisol, which is produced by the adrenal gland in response to stress, and the decrease in adrenocorticotropic hormone secreted by the pituitary gland also warn of their presence, indicating that the root of the problem is in the brain. This highlights dysfunction of the hypothalamic-pituitary-adrenal axis, which may be linked to fatigue, increased heart rate or dizziness.

4. When will our personalized treatments be available?

To date, no drugs have been approved to treat persistent covid, so doctors resort to relieving symptoms on a symptom-by-symptomatic basis. In some cases, and due to desperation in relieving symptoms, patients self-administer unconfirmed treatments.

In this sense, it is very important to delve deeper into why some people have prolonged symptoms and others do not. We may find that genetic or hormonal factors, or perhaps the state and composition of the gut microbiota, the group of microorganisms that live in our digestive tract, affect it. Predicting who will experience these symptoms and pinpointing their causes will bring us closer to an effective treatment.

Currently, therapeutic strategies aim to control symptoms, particularly those that are neurological or affect the cardiovascular system. Experiments are currently underway with rehabilitation therapies or drug cocktails such as steroids, anti-inflammatories, antivirals, anticoagulants, dietary supplements or cell therapy. However, its effectiveness remains to be tested.

Although there are more than 200 ongoing clinical trials investigating permanent covid treatment, more randomized trials are needed. Most cases require combination therapy and we need to consider how this pharmacological weapon can be used for maximum effect. This is likely to involve combining antiviral and immunomodulatory drugs (to improve the immune response).

Better understanding the causes of persistent covid and figuring out how to treat it provides an opportunity to learn about the disease, which requires an international and coordinated effort. Public and private funding provides basic support, but in the face of the growing avalanche of patients, no effective therapy has yet been found. The investigation should be expedited when the results are encouraging.

Despite the loosening in containment policies, we must continue to protect ourselves and be vigilant against the disease. No matter how optimistic our estimates may be, persistent covid is a reality that can cause chronic morbidity and disability in millions of people, with major socioeconomic and health system implications.

Recognition, diagnosis and access to healthcare are patients’ rights. Until the disease and effective treatments are better understood, the best we can do is avoid being infected or reinfected with covid.

Sonia Villapol, Assistant Professor, Houston Methodist Research Institute

This article was originally published on The Conversation. Read the original.