Animal Models of Post-Acute COVID-19 Syndrome: A Call for Longitude Animal Studies

Jingyi Dai Fanyi He Qian Chen Qiujing Li Liping Zhao Yingrong Du ^*

• The Third People’s Hospital of Kunming City, Kunming, Yunnan Province, China

Animal models are indispensable for unraveling the mechanisms underlying post-acute sequelae of SARS-CoV-2 infection (PASC). This review evaluates recent research on PASC-related perturbations in animal models, drawing comparisons with clinical findings. Despite the limited number of studies on post-COVID conditions, particularly those extending beyond three months, the available research provides valuable insights. Three hallmark features of PASC—lung fibrosis, hyperglycemia, and neurological sequelae—have been successfully replicated in animal models, paving the way for mechanistic discoveries and future medical interventions. Although most studies have focused on post-COVID conditions within 14–60 days post-infection, they still offer critical reference points for long-term research. The review also explores potential mechanisms of persisting immune misfiring, a key factor in the chronicity of PASC symptoms. Challenges in modeling PASC are also discussed, including the limited genetic diversity in inbred animal strains and difficulties in accurately identifying PASC-affected individuals. To address these issues, we propose methodological improvements, such as comparing individual animal parameters with control averages and incorporating genetically diverse populations like collaborative cross models. These strategies will enhance the identification and characterization of PASC endotypes in animal studies. By integrating findings from animal models with clinical manifestations of PASC, future research can provide more valuable insights into its mechanisms and support the development of effective therapeutic strategies. Finally, we emphasize the urgent need for longitudinal studies in animal models to fully uncover the mechanisms driving PASC and guide interventions to mitigate its public health impact.