Study Launched to Analyse Immunopathogenic Mechanisms of Long COVID and the Effects of Vaccination in Patients with Persistent COVID-19 Symptoms

Researchers from the University Institute in Primary Care Research Jordi Gol i Gurina (IDIAPJGol), the Barcelona Institute for Global Health (ISGlobal) and the Vall d’Hebron Research Institute (VHIR) have launched a new study to investigate the immunopathogenic mechanisms of long COVID. The study will also assess the effects of COVID-19 vaccines in these patients and determine how long these effects last. This collaborative study has been made possible by the logistical and operational support of the Daniel Bravo Foundation and the participation of the Catalan patient support group Col·lectiu d’Afectades i Afectats Persistents per la COVID-19.

“Long COVID is the term used to refer to cases of patients who still have persistent symptoms more than four weeks after the onset of the disease,” explains Anna Berenguera, the study coordinator at IDIAPJGol. “We estimate that up to 10% of patients who have been infected develop persistent symptoms and there appears to be no relationship between disease severity and the probability of developing long COVID”. It is thought that these chronic symptoms can persist for six months or more.

“The most common profile for a patient with persistent Covid-19 symptoms is a woman under 45 years of age, who did not require hospitalisation for the original infection but who is living with symptoms months later,” explains Dr Jordi Rello, principal investigator of the Clinical Research & Innovation in Pneumonia and Sepsis (CRIPS) group at the Vall d’Hebrón Research Institute and Professor of Medicine at the International University of Catalonia. “These patients were young and healthy and many of them are now living the lives of an elderly person. This is why it is so important to stress the need to vaccinate young people,” he insists.

Possible Causes of Long COVID

There are a number of theories about the causes of persistent symptoms in patients infected by the SARS-CoV-2 virus. One is that the virus or viral proteins persist in certain areas of the body and produce an inflammatory response. Another hypothesis is that the viral infection gives rise to a very strong inflammatory response, which damages various tissues. A third possibility is that the infection triggers the production of autoimmune antibodies that later attack various tissues in the body. “We need to understand the causes and find biomarkers so that we can develop effective treatments, follow up on these patients and improve their quality of life” explains Gemma Moncunill, principal investigator of the ISGlobal study.

Effects of Vaccination on Patients with Persistent COVID-19 Symptoms

It is thought that COVID-19 vaccines may benefit some people with long COVID and decrease the intensity of their symptoms. It is not yet known whether all the currently available vaccines could have the same beneficial effect or how long these effects will last and what the underlying mechanisms might be. The mechanisms could be related to the elimination of persistent virus or viral proteins or the improvement might be mediated by a nonspecific immune response.

An earlier IDIAPJGoL collaborative study that enrolled more than 2000 participants described the clinical profiles of patients with long COVID and how the syndrome affects their quality of life. That collaboration involved the collective of people with persistent symptoms (Col·lectiu d’Afectades i Afectats Persistents per la COVID-19) and the Catalan Institute of Health.

The objective of the new study, which was launched on 20 October and will analyse data from a sample of about 300 people, is to investigate the immunopathogenic mechanisms of long COVID by analysing the profiles of antiviral antibodies, autoimmune antibodies, and biomarkers of tissue damage as well as immune activation and inflammation. The study will also assess the effects of COVID-19 vaccines. All participants must complete several visits over the course of the two-year study and blood samples will be taken at each visit.

This study is being carried out in collaboration with the patient support group Col·lectiu d’Afectades i Afectats Persistents per la COVID-19 and is funded by the Daniel Bravo Andreu Private Foundation.

“The members of our group are very pleased to take part in this study. We understand that without research we cannot be cured. We’ve always been committed to collaborative research and this study offers a window of hope for many of our members (#covidpersistentes),” explains Sílvia Soler, the spokesperson for the patient support group.