The world fears replication-competent vaccines even though we've used them for decades for stuff like measles, yellow fever. Why?...
I get the creepy factor. The idea of putting something in your body that replicates indefinitely...but most of course just die out cuz they're genetic weaklings (attenuated)...
I raise this in an effort to tie together two disparate facts:
*Claimed 92% efficacy for adenovirus-based Sputnik V Russian vax is much higher than other adenovirus vaxes from J&J, AZ.
AND- their vax has rep-competent adeno...
Which could easily explain an apparent superiority of Sputnik relative to J&J, AZ. Replication-competent vaccines produce antigen far longer than replication-incompetent.
PS to be clear I don't think replication-competent adeno in Sputnik V was intentional.

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More from @hjelle_brian

3 May
Again, don't get hung up on that magic herd immunity number. For indefinite future, we in 1st world must settle for an uneasy truce w/virus for many months, maybe years. What will that look like?...
The reality is that once again American health will be balkanized. We will have pockets of those who thru volition or poor access will harbor virus longer among them...
The biggest threat to our uneasy truce with virus will come from variants spawned from without, from other countries with vast, unvaccinated populations. Some of those variants will display increasing ability to defeat our waning immunity...
Read 4 tweets
3 May
We are indeed hearing of persons fully vaccinated getting gravely ill, dying of COVID. This is as predicted, since the vaccines change your odds but they aren't miracles. You can overwhelm them, for example, with extraordinarily intense exposures...
There are absolutely spectacular variations in the inoculum (dose) of virus to which COVID patients were exposed. Literally millions-fold or more...
Needless to say, massive exposures of live virus can overwhelm vax immunity. These are the kinds of exposures you're more likely to see in bars, restaurants, concerts packed with people...
Read 4 tweets
2 May
This is an attempt to plot a "virus fitness landscape".
This bit of esoterica will possibly assume great importance in our long-term affliction with SARS-CoV-2. I dread explaining cuz is complex... Image
The x and y axes are showing the virus' genetic changes. Because mutations can cross-interact, we would need >2 dimensions to properly plot, but we're only human...
The plot shows stepwise movement of a reasonably fit virus to go to a higher peak.
Each step is incremental and does only modest changes to its fitness. That is a key point...
Read 6 tweets
30 Apr
At risk of being tedious pedant I will say it again: there is no life form- animal, vegetable or other- that isn't EXACTLY as evolved as we.
Moreover, we have a common ancestor.
I except viruses. Not a life form.
The best receipt I have- there are others- is called the genetic code. Image
Read 4 tweets
26 Apr
Common lay question: why don't we have a vaccine for the common cold?
This is kind of amusing in that recent events with COVID vax really highlight the problem. Thread...
Let's forget for a moment that a few cold viruses occasionally cause serious disease. Like adenovirus. Take as operating assumption that cold viruses cause only annoying, non-lethal maladies...
You now have extremely common, inevitably nonlethal illness. So right up front, NOBODY better die or get crippled from your new vax. But it gets worse...
Read 6 tweets
24 Apr
Despite my many tedious academic threads, I don't actually expect my non-virologist tweeps to come out knowing all about virus RNA, immune escape, or receptor binding.
Here is the ONLY thing that I think yall should try to learn, the thing most important. Thread...
Viruses, like many "life forms" live on the edge of viability. They haven't solved it all either. They can be defeated. In many cases we have the tools!...
A virus' success is measured in its R value, or reproductive value. Basically, how many people get infected from each infected person...
Read 9 tweets

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