The only thing that is going to keep the curve flat (this is kind of a mind-numbing terminology) is human behavior. Exponential growth is still a thing, and we aren't anywhere near achieving herd immunity.
(a physician friend mentioned the other day that we're not truly certain yet that COVID 19 sufferers cannot be reinfected, although that's the popular assumption. So there's also that)
Out of curiosity because I have little to no knowledge of immunology: what do you think that means if someone that already had the disease can be reinfected? Does that have any implication on the efficacy of a vaccine?
The physician I talked to was basically trying to rain on my parade when I said "hey, it will be great when there's a vaccine and we can all go back to normal." Maybe, maybe not.
I don't know that much about it, but sometimes people infected with a coronavirus can get sick again, not as ill as they were previously, but contagious. [1] COVID 19 hasn't been analyzed well enough, long enough to say for certain.
There were some scary stories early on, a month or two ago, about people becoming reinfected with full blown cases of COVID 19, but they really felt more like uncertain anecdotes. I strongly suspect the immunologists will know a lot more about this in just a few weeks. Researchers are already giving people test vaccines and sending them out into the world.
In a nasty - hypothetical - reality where people regularly get reinfected: things do not go back to normal, and we have to figure a lot of difficult social stuff out.
Unfortunately, yes. Consider the common cold: yes, it does mutate fast, but the other big barrier to producing a vaccine is that immunity to it doesn't last very long at all. So if COVID-19 immunity truly doesn't last long, that's a problem.
I doubt this is likely to be the case, though. Antibodies to SARS seemed to have long lifetimes (several years), and COVID is likely to be similar. It is certainly possible that for some people, immunity fades much faster for reasons specific to that person, and that may be what is being picked up in these reports.
It is also possible it's just shoddy lab work. There has been a ton of that going around lately, and it's not just caused by pressure from the situation. Not all scientists are equally competent....
(Disclaimer: my knowledge of immunology is likely little better than yours, but I did at least used to be a Real Scientist in a different field.)
The reason that antibodies to SARS have long lifetimes is because it is a much worse hit than COVID-19 in most cases, you can take the CFR as proof of that. Harder hit to the immune system but you survive: immunity will last longer is a good rule of thumb.
(a physician friend mentioned the other day that we're not truly certain yet that COVID 19 sufferers cannot be reinfected, although that's the popular assumption. So there's also that)