‘In SARS, a type of “priming” of the immune system was observed during animal studies of SARS spike protein-based vaccines leading to increased morbidity and mortality in vaccinated animals who were subsequently exposed to wild SARS virus. The problem, highlighted in two studies, became obvious following post-vaccination challenge with the SARS virus [2]. found that recombinant SARS spike-protein-based vaccines not only failed to provide protection from SARS-CoV infec- tion, but also that the mice experienced increased immunopathology with eosinophilic infiltrates in their lungs. Similarly [3], found that fer- rets previously vaccinated against SARS-CoV also developed a strong inflammatory response in liver tissue (hepatitis). Both studies suspected a “cellular immune response”.’

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7142689/#!po=1.92308

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7142689/pdf/main.pdf