Long COVID is not a single disease but a complex syndrome involving a range of persistent symptoms. People suffering from it report overwhelming fatigue, memory lapses, "brain fog," difficulty concentrating, sleep disturbances, and neurological symptoms that can last for months or even years after the initial infection. Despite its growing prevalence, the pathogenesis of PCC remains poorly understood. To explore the underlying mechanisms of this condition, the team monitored golden Syrian hamsters for 60 days post-infection. They examined viral persistence, how the immune system responded, histopathological findings, and how the animals behaved over time. The animals showed traces of viral RNA long after the infection, sustained immune disruptions, and certain behavioural changes evoking long COVID symptoms in humans.
Although no animal model can fully replicate the variability of long COVID in humans, these findings suggest that hamsters could be an important tool for investigating the biological roots of the syndrome.
Researchers hope this model will accelerate the search for answers, helping to identify risk factors, test possible ways to prevent long COVID, and eventually design treatments that target its underlying causes.
Ruiz-Casas C, Tarrés-Freixas F, Roca N, Pérez M, Cantero G, Martín L, Olvera A, Ruiz-Riol M, Brander C, Usai C, Vergara-Alert J, Segalés J.
Long-term neurocognitive outcomes of SARS-CoV-2 infection in a hamster model.
Front Microbiol. 2025 Aug 14;16:1646616. doi: 10.3389/fmicb.2025.1646616
About EPIVINF project
The EU-funded EPIVINF project aims to understand how acute viral infections alter the epigenetic regulation of host genes that are governing immune control and neurological health. EPVINF will also investigate how pre-existing epigenetics impact immune response to vaccination. The study will focus on HIV and SARS-CoV-2 as two human viral pathogens that affect millions of people around the globe and share common features that require further research. The study also aims to identify the predisposing factors leading to specific clinical symptoms and how these could be employed as novel therapeutic targets.