Two pieces of good news for inactivated vaccines today:
1. Results from Uruguay indicate Sinovac protects 95%/92% against death/ICU cases
2. Neutralization assays indicate antibodies elicited by Covaxin only drop 2.7x in potency vs B.1.617.2 (Delta)
Details below
Uruguay results:
Sinovac: deaths/ICU/symptoms⬇️95/92/61% (HCWs and 18-69yo)
Pfizer/BioNTech: deaths/ICU/symptoms⬇️94/94/78% (HCWs and >80yo)
Confirms Sinovac works well vs. severe disease even with some breakthrough cases. Overall similar to Chile reuters.com/world/americas…
These data confirm 2-dose Sinovac, an inactivated virus vax, is similar to 1-dose J&J or 2-dose AZ. All these (and Sinopharm+Covaxin) have breakthrough risk of 20-50% (depending on dose spacing), but still protect >90% against death.
Overall, inactivated vaccines are useful
The other news for inactivated vaccines is a finding that Covaxin-induced antibodies drop in potency 2.7x on B.1.617.2 vs original SARSCoV2. This is not great of course, but it compares well to 6x for Pfizer/BioNTech reported earlier this week.
This Nature "explainer" is unfortunately not a very good one. It's better than the previous Nature article, but some poorly conceived arguments are pushed while some data in print are swept under the rug.
The good things first: there's no begging the question, i.e. no conclusion is presumed that all other theories must definitively rule out before being considered. There's no overeliance on conflicted people with poor track records.
The three problems I see on quick read: 1. It repeats Shi's blanket statement of sarbecoviris seronegativity in the miners without specifying the speaker, while not mentioning the more granular description of positivity by PhD student Huang.
There have been a lot of stories recently on the search into COVID19/SARSCoV2 origins, but they have been written to tell stories of intrigue or mystery, not to summarize known facts.
Thus I thought it might be useful to succinctly summarize what we actually know...
1/n
I'll say from the outset we know zero about where sarscov2 itself came from, so the only facts we can list are those that could be proximally relevant. That is, each of these facts is either about SARSCoV2 discovery or just one potential step removed from SARSCoV2 origins.
2/n
First, the briefest bit of background: SARSCoV2 is in the clade or coronaviruses called the sarbecoviruses, named after its first known member, SARSCoV1, the cause of SARS discovered in 2002. SARSCoV1 and SARSCoV2 are 80% identical.
3/n
"Andersen, a professor at the Scripps Research Institute, tweeted this week that "we seriously considered a lab leak a possibility," but reconsidered upon further review of the evidence..."
"Andersen’s use of the term “lab leak” could be confusing, however, because he was talking in the emails about the question of whether the virus had been modified or engineered."
The advantage of the RNA vax is their simplicity. They encode only the spike protein because it's the viral protein targeted by most of the antibodies that prevent viral entry. Another way to put it is Abs to the right place on spike are sufficient to block entry. (image Siemens)
The adenovirus vax also encode only spike but express it from Ad. Both types elicit high levels of neutralizing antibodies (nAbs) after just one dose. RNA is better here; in fact 1 dose of RNA gives you similar nAb levels to natural infection.
Interesting excerpt:
'Had the WIV been actively working on RaTG13 during the seven years since they discovered it? Peter Daszak said no: they had never used the virus because it wasn't similar enough to the original SARS...
'..."We thought it's interesting, but not high-risk," he told Wired. "So we didn't do anything about it and put it in the freezer."
A lesson on proper trial design: Was thinking, if nAb levels at 3% of convalescent plasma (CP) prevent severe COVID (nature.com/articles/s4159…) then infusing 1U of CP (5% body volume) should prevent death.
Of course it was the @nytimes who wrote the obituary for convalescent plasma. Maybe nothing factually wrong in their stories, but their writers generally lack the training to dig deeper and find the signal in the noise.
"When a treatment fails, which is often, it can be difficult for its strongest proponents to let it go. Eventually, studies did emerge to suggest that under the right conditions, plasma might help."
Sloppy @nytimes. 1st sentence implies CP failed. 2nd says success. Which is it?