Quote Originally Posted by Liverpooldawg View Post
With those two you get real sick, real quick. There is little to no asymptomatic transmission. That makes it relatively easy to detect, trace, and isolate once you know what to look for.
That seems to be a reason why those two only infected a lower number of people, but I'm not sure it speaks to why they are not still around today. My understanding is they are not still around today because they did not mutate, or only did so minimally and not enough to overcome immunity. For example, even if the whole world gets covid, we will build immunity to it and it will go away unless it mutates. I'm no expert, this is just my understanding from what I've read, that the key to it staying forever will be whether or not it mutates. History suggests there will be a second wave, but it will die out.

From what I have read, coronaviruses in the past have seen a second wave. Sars 1 in 2002 and Mers in 2012 were the two most recent, and both had second waves. Both were far more deadly than COVID 19, but not near as transmissible. But both largely completely disappeared after that second wave without a vaccine, and 12-18 months after showing up. There is no vaccine for sars or mers, or for any coronavirus.

Compare that to swine flu in 2009, which was not a coronavirus but an h1n1 virus akin to the 1918 Spanish flu. There was a vaccine developed and administered to Americans for the swine flu, but it largely went away on its on due to not mutating like the virus we commonly refer to as the flu.

So, history of coronaviruses tells us that there probably will be a second wave, not sure how strong, but this virus will run its course and go away without a vaccine, likely 12-18 months since it started. Interestingly, that 12-18 month period is the same time we've been told to expect a vaccine to be ready.