Catalan hospitals join key research on reasons for serious Covid-19 symptoms

Some young people with no previous conditions have developed serious symptoms due to Covid-19 since the beginning of the pandemic, with some having to spend time in the ICU or even dying.

While most young people have no symptoms or only mild ones, experts could not find any reasons for the different reactions in people with same medical profiles until now.

Yet, two studies published by 'Science' magazine on Thursday cast some light on it.

It is the result of the work of an international consortium called COVID Human Genetic Effort, led by the American University of Rockefeller, in New York, and INSERM, of France, which has also been joined by the research centers of some Catalan hospitals.

Catalan institutions part of the project

The centers that gathered samples of patients in the first months of the pandemic and helped sequence and analyze the data are Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Hospital Universitari de Bellvitge, Vall d'Hebron Institut de Recerca (VHIR), Hospital Universitari Vall d'Hebron; the Can Ruti campus, including Hospital Germans Trias i Pujol and IrsiCaixa; Hospital Universitari MútuaTerrassa, the Fundació Docència i Recerca MútuaTerrassa, and Centre Nacional d'Anàlisi Genòmica (CNAG-CRG).

Institució Catalana de Recerca i Estudis Avançats (ICREA), Institut d'Investigacions Biomèdiques de Barcelona-CSIC, Hospital del Mar and Universitat de Vic are also part of the consortium.

The two papers lead to the same conclusion: 15% of the young patients with serious Covid-19 symptoms have alterations in their interferons, the proteins that first respond to several viruses activating nearby cells that usually heighten their anti-viral defenses.

In over 10% of the cases analyzed, the study found that their own antibodies were boycotting their own immune system.

Around 3% of the young patients with unexplained complications due to the pandemic were found genetic mutations in eight genes not existing in a similar number of asymptomatic patients.

This list of mutations, which could also be relevant for other viruses, might extend as new cases are studied.

Anyone can end up in ICU

"An important message is that no one is ruled out from ending up in an ICU," said Aurora Pujol, geneticist and professor at ICREA, in IDIBELL.

"One person can be 25 and develop a serious Covid-19 infection if they have unfavorable variants of genes of these kinds."

"Now that we know one of the molecular causes of why some young people develop serious symptoms of the disease we can improve our therapeutic options, like treatment with interferon," she added.

"What raised our curiosity was the fact that three patients with SARS-CoV-2 infection who developed a serious pneumonia and who, for a previous illness, we knew that had antibodies that jeopardized their immune system," explained David Dalmau, researcher at MútuaTerrassa.

"We thought: can it be that they are not isolated cases and that this situation is the trigger for the serious symptoms of other people? And for this reason we began to analyze whether other patients had these antibodies," added Javier Martínez-Picado, researcher ICREA at IrsiCaixa.

"This strengthens the idea that these antibodies have a role as cause for these serious forms of the disease, and not as a result," expressed Doctor Andrea Martín, researcher at Grup de Recerca d'Infecció en el Pacient Pediàtric Immunodeprimit at VHIR.