Long COVID Symptoms

The goal of this observational study is to improve the understanding of the biological mechanisms underlying long COVID and to identify molecular biomarkers that may support its diagnosis, prognosis, and future precision medicine approaches in adults with long COVID, adults who have fully recovered from COVID-19, and healthy control participants. The main questions it aims to answer are: * What molecular, immunological, epigenetic, and microbiome profiles distinguish individuals with long COVID from recovered COVID-19 participants and healthy controls? * How are viral persistence, immune dysregulation, and alterations in the gut-immune axis associated with the development and clinical manifestations of long COVID? * Which molecular biomarkers may improve disease diagnosis, patient stratification, and the identification of potential therapeutic targets? Participants will: * Undergo clinical evaluation and provide information about their medical history and symptoms. * Provide biological samples, including blood and, when clinically indicated, intestinal biopsy tissue collected during routine colonoscopy procedures. * Undergo comprehensive molecular analyses, including immunological, epigenetic, transcriptomic, proteomic, and microbiome profiling. * Have their clinical and molecular data integrated using advanced computational approaches to identify biological signatures associated with long COVID. The results of this study may improve the understanding of the biological mechanisms underlying long COVID and support the development of novel biomarkers and future precision medicine approaches for diagnosis, prognosis, patient stratification, and therapeutic target identification.

A small-scale test of the intervention, trial design and methods to explore the cumulative effectiveness of two commonly used prescribing strategies for patients with long COVID: Treatment A - prescribing a specific homeopathic remedy for long COVID, plus or minus Treatment B - a course of individually tailored treatment by a homeopath. Both interventions compared to usual care

The goal of this observational study is to deepen our understanding of long COVID by determining the prevalence of the main complications and medium- to long-term sequelae of COVID-19 in Navarre. Sociodemographic variables such as age, sex, ethnicity, smoking history, and comorbidities will be collected, as well as clinical and disease management variables such as persistent COVID-19 symptoms at 3 months, all with the aim of characterizing patients with long COVID. All patient data will be collected in a single visit.