This article is talking about 2012 efforts at developing a SARS coronavirus vaccine.
Immunization with SARS Coronavirus Vaccines Leads to Pulmonary Immunopathology on Challenge with the SARS Virus
Published online 2012 Apr 20. doi: 10.1371/journal.pone.0035421
These SARS-CoV vaccines all induced antibody and protection against infection with SARS-CoV. However, challenge of mice given any of the vaccines led to occurrence of Th2-type immunopathology suggesting hypersensitivity to SARS-CoV components was induced. Caution in proceeding to application of a SARS-CoV vaccine in humans is indicated.
Other info on current situation with COVID-19 and COVID-19 vaccines: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3335060/
Interview with expert who sites the above article in the context of current concerns about COVID-19 vaccines.