Clinical and Biological Characterization of Post COVID-19 Syndrome

Association of Symptoms, Clinical and Biochemical Characteristics in Post COVID-19 Syndrome: a Case-control Study

The goal of this observational study is to describe the symptoms that persist for more than 12 weeks after the acute episode in participants who had COVID-19, and compare the functional, socioeconomic and occupational effects with a post-COVID-19 control group without persistent symptoms after the COVID-19 acute event.

The main questions it aims to answer are:

• What are the characteristics of symptoms that persist for more than 12 weeks in participants who have had COVID19 in the last year?
• What are the health-related quality of life and psychosocial effects in participants with persistent symptoms of COVID-19, compared to a post-COVID-19 control group without persistent symptoms after the acute episode of COVID-19?

Two groups of cases and one group of controls will be included. A group of cases with persistent respiratory and/or cardiovascular symptoms (cardiorespiratory cases), and another group with persistent non-cardiorespiratory symptoms.

Participants who report at least two symptoms of intensity greater than or equal to severe will be classified as non-cardiorespiratory cases.

Controls will be participants with a history of confirmed SARS-CoV-2 infection, but without current or past persistent symptoms (ie, who resolved their symptoms during the acute episode or whose symptoms did not persist more than 4 weeks after onset).

Controls will be matched to cases by sex, age (with a margin of up to ±5 years), and time since diagnosis of the COVID-19 episode considered as the origin of post-COVID-19 symptoms in the cases (with a margin of of ±30 days).

The visit will include the application of the questionnaires for the evaluation of symptoms and quality of life associated with health, the clinical evaluation and the extraction of a blood sample.

The extraction of a blood sample will allow biochemical determinations, the complete blood count and vitamin D level to be carried out. Subsequently, an aliquot will be reserved for mechanistic evaluation (inflammatory markers, immunological and microRNA studies).

Two groups of cases and one group of controls will be included. A group of cases with persistent respiratory and/or cardiovascular symptoms (cardiorespiratory cases), and another group with persistent non-cardiorespiratory symptoms. For participation in the study, people who meet the following inclusion criteria and none of the exclusion criteria will be considered.

Inclusion Criteria:

• Age equal to or greater than 18 years;
• Documented SARS-CoV-2 infection by PCR or antigen test;
• Ability to understand the objectives of the study;
• Acceptance to participate in the study and willingness to sign the informed consent.
• Permanent residence in Buenos Aires Metropolitan Area.

Exclusion Criteria:

• Women who report being pregnant, who are in the puerperium or lactation period at the time of the evaluation.

• People with known chronic debilitating conditions, defined as:

  i. heart failure, ii. symptomatic Coronary Heart Disease, iii. Diagnosis of cancer in the last 5 years iv. symptomatic anemia, v. chronic obstructive pulmonary disease or greater than moderate asthma, vi. heart valve disease more than mild, vii. cognitive impairment prior to the diagnosis of COVID-19, viii. diagnosis of schizophrenia or depression, ix. any other condition that, at the discretion of the treating professional or the research team, may explain or justify the aforementioned symptoms.

• Participants who are undergoing an acute pathology or who have undergone it in the last 4 weeks. In this case, they may be contacted again, after the period of time considered acceptable by the treating professional or the research team to invite them to participate.