Mechanistic insights into Long COVID in hamsters

Using a golden hamster model, Frere et al. compared the short- and long-term responses to SARS-CoV-2 and influenza A virus (IAV) infection to better understand the mechanisms that account for persistent COVID-19 symptoms. At 3 days post infection (3dpi), both viruses induced a robust type I interferon response that cleared acute infection from the respiratory tract. Both viruses also induced an acute inflammatory response in peripheral tissues such as heart, kidney and lung, but by 31dpi (which would be defined as Long COVID in humans), SARS-CoV-2-infected hamsters had greater evidence of peripheral organ damage than IAV-infected hamsters. Furthermore, SARS-CoV-2-infected hamsters uniquely had prolonged inflammation in the olfaction system and various brain regions including striatum and cerebellum. This inflammation was evident in the absence of infectious virus and was associated with behavioural changes.