While the two SARS viruses are still fairly different, I was wondering if there was any study of whether there was any level of immunity conveyed by SARS-CoV-1, against the novel strain. Even when there's a mismatch, there's often some degree of protection, such as presentation of asymptomatic and subclinical infection rather than clinically significant levels of symptoms.
I am not aware of such a study yet, but you may be interested on the following:
COVID-19: immunopathology and its implications for therapy.
Nat Rev Immunol. 2020 Apr 09.
Article COVID-19: immunopathology and its implications for therapy
If that immunity was there in the first place, it should have protected all these infected or dead people or don't you think?
Maurice Ekpenyong, I'm not sure what you mean. I think there's a language barrier issue here. Whether they're protected is the question that I asked. If you're suggesting that nobody should be getting sick, that doesn't make sense, because only a small fraction of the world's population became infected with the original SARS virus.
SARS-COV-1 is said to provide immunity that lasts only for about three years, the same goes for MERS-COV. If memory serves, I think it is well over three years since we had the SARS-COV-1 problem. So, whatever immunity that the virus left behind must have faded away completely. Please see the attached documents for better information.
https://www.cell.com/immunity/pdf/S1074-7613(20)30120-5.pdf.
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(20)30788-1/fulltext