Unagi wrote: Fri Dec 24, 2021 1:58 pm
What’s the difference between the flu world where they try and make a vaccine for “this year’s flu”, and the work being done with Covid vaccines and boosters that may or may not be as effective against the current strain of Covid.
The flu has a "natural" cycle it follows - it's truly seasonal based on where you are in the world at any given time. Each year nature comes up with a slightly modified version of the strain(s) that circulated in years prior and they tweak the vaccines to adjust for it. For the influenza viral genome, it's apparently more or less "stable" and the combinations that emerge are "expected" in the sense that we know what combinations will result in a flu virus that (1) spreads between humans and (2) causes us illness. As a reminder, influenza is primarily a disease of aquatic water fowl, but for various reasons, it jumps to different animal species and ultimate,y to us. Those "jumps" allow the viral genome to shuffle a bit, which is where the vaccine formulation comes in. Every once and while something unforseen happens (i.e. 1918, 1976) and the genetic reshuffling isn't something we are expecting and the potential for a more severe variant emerges. To be clear, when the genome shifts, it changes how the virus "presents" itself to your body - it changes the shapes of the proteins or the makeup of the coating of the virus that your body uses to try and identify it as self vs non-self.
For SARS-CoV-2, there is no "cycle" that its in. It's not "seasonal" or "endemic" (despite what you might have heard), it's a raging pandemic right now - still, after almost 2 years.
There is no comparable event in our collective lifetimes and trying to develop a vaccine for a newly emerged human pathogen that is still circulating (and mutating) seems like a large whack-a-mole effort, largely in part because it continues to circulate (and mutate) unchecked.
For influenza, there is more of a host balance - it's not something that we've never seen (with the noted exceptions above) before on Earth, it's just moving through our area based on the time of year. SARS-CoV-2 knows no limits. Yes, it would seem there are factors that encourage spread (humidity possibly, temperature (indoor vs outdoor activities)) but it has not stopped circulating. Your body knows influenza - it has memories of it. Prior exposure (and vaccinations) give you an advantage against future exposures (even if it's not a 100% match). For SARS-CoV-2, we're all too immunologically naive. And now the virus is specifically evolving to evade immunity - both from vaccinations and prior illness.
Until we get it to stop circulating (masks being key here, but not the only way) we are on a treadmill. And if I had to put my money on humans or the virus figuring out how to break this cycle, I'm better on the virus. Mainly because it's already figure out how to increase spread and bypass immunity in the first year we hit it with a vaccine. What will 2022 bring?
Oh hey look, it's drink o'clock.