Some Thoughts On The COVID-19 Mid-Term

 

 Cut-and-paste from a comment elsewhere on a news story about Dr. Fauci's remarks on the timetable for a return to "normal", and expanded on here. Particularly, this graf:

"I mean, if normal means you can get people into theater without worrying about what we call a 'congregate setting.' Superinfections. If you can get restaurants to open at almost full capacity, if you could have sporting events to be able to be played with spectators, either in the stands or in the arena, then I think that's going to be well, well into 2021 and perhaps beyond. I think one of the things that will be clear that our sensitivity to the potential devastating effects of a pandemic will be extraordinarily heightened. And I don't think that we will have the normal way of interacting with each other, particularly in the sense of wearing masks, which I think will become very commonplace as it is in many countries in Asia, even outside of the context of a pandemic outbreak. Again, I think it's many months."

We’re probably looking at a widely-deployed vaccine in the mid-2021 timeframe. Do not be surprised to see this pushed back as failures occur among the front-running vaccine candidates.

 

We will not know the durability of the immunity it confers. In that regard, it will be a phase III test (the actual term used by vaccinologists is phase IV). We may need to get revaccinated as often as twice yearly, forever. I am modestly hopeful on that front, because SARS-CoV-1 reactive T-cells have been documented as long as 17 years after infection. If T-cell immunity is the primary response, we could be golden.

 

We know that B-cell (antibody) immunity declines rapidly. A recent large-scale UK study showed antibody prevalence dropping from 6% to 4.4% in three months. This is strongly suggestive that we should not expect sterilizing immunity from a vaccine, but only protection from disease. This is not an uncommon outcome. The injected Salk (inactivated virus) polio vaccine has this effect also.

 

Because we will not get sterilizing immunity, we cannot rule out disease transmission even among the vaccinated. And because a vaccine will only confer protection on a (large) fraction of individuals, viral transmission will continue. The hope is that viral loads among the infected-but-vaccinated will be sufficiently low so as to reduce or eliminate transmission, but we cannot count on it.

 

So I can see what Fauci’s saying as not improbable. Masks, occasional lockdowns (hopefully becoming more infrequent as we find out how effective the vaccine(s) is/are) and other measures will probably continue to be necessary for a while.