Why do people think you suddenly lose all immune memory of meeting a virus? You don’t. It might become undetectable in the assays used, but biologically it’s still there. What we need to know is how long lasting and robust it is. That’s a completely separate issue. #COVID19

We know from other seasonal coronaviruses that reinfection occurs throughout life. The questions that need addressing are: 1 does this virus exist as a single antigenic type? Do the antibodies elicited from your first infection/vaccine, confer broad protection (optimistic!)

2. How quick is the immune response on reinfection, are you likely to shed virus for a while before it’s neutralised?

3. Will subsequent infections be significantly attenuated? How will aging affect this?

4. Will increased immunity in the population drive the virus to mutate at antigenic recognition sites if or when it establishes as a seasonal virus?

5. Will escape mutants be an issue for vaccine campaigns?

My scepticism around the utility of serology testing diagnostically for SARS-CoV-2 remains the same. Not that it can’t tell you about exposure history, but that it’s way too early to say what it means for that individual in the long term. Btw If the answer to Q1 is YES - bingo!!