ncbi.nlm.nih.gov/pubmed/2170159
So overall, for this *common-cold coronavirus*, pre-existing antibodies reduced risk of infection, but re-infection could occur a year later although with reduced symptoms. (4/5)
- different coronavirus, 229E vs #SARS_COV_2
- all volunteers probably been infected w/ immunity prior to 1st infection, which is not true for #COVID19
- 229E causes mild cold, so hard to assess disease severity
(5/5)