Они обалдели!

The Sputnik V vaccine Ad5 vector is evidently replication competent. The makers apparently neglected to delete E1, so getting this vaccine means being infected with live adenovirus 5.

Hence Brazil’s regulator correctly rejected it.

Adenovirus-vectored vaccines like J&J, AstraZeneca, and Sputnik V use infection with adenoviruses, common pathogens that usually cause common colds.

But to increase safety and decrease risk of side effects, most vaccine vectors delete the AdV E1 and E3 genes.
E1/E3 deletions are standard in Ad-vectors. Deleting E1 prevents the virus from replicating and deleting E3 prevents it from interacting with the immune system.
This results in a vaccine vector that causes a transient infection, due to the vector’s inability to complete its replication cycle. When I got J&J it infected my cells, began expressing viral proteins, including SARS-CoV-2 spike, and then hit a block because of the E1 deletion.
Sputnik V is a heterologous Ad-vectored vaccine: the prime dose is an Ad26-vectored vaccine (like J&J), followed by a booster that uses Ad5. This was apparently found in testing the Ad5 booster but I can’t emphasize how sloppy this is.
When making adenovirus-vectored vaccines, once you’ve deleted a region of the genome, it doesn’t just reappear out of nowhere. The presence of replicating virus suggests E1 was either not deleted or it recombined during manufacturing with a full length AdV genome.
And while strong statements from Gamaleya and the RDIF dispute the findings, this isn’t the first observation that the Sputnik V doses submitted to regulators aren’t consistent with the phase 3 trial results published in Lancet.
Slovakia’s drug regulator previously rejected a batch of Sputnik V for being substantively different than the batches reported in Lancet. The EMA has also said they have insufficient safety and QC data to authorize it in the EU.
This is disappointing. Ad-vectored vaccines are easier than mRNA vaccines to store and distribute, and are going to be important for vaccinating people in hard-to-reach places. Despite rare side effects, they are generally considered safe and trial data shows they are effective.
Safety concerns have already reduced enthusiasm for these vaccines, and an unforced error like this further amplifies those concerns and decreases trust in the technology itself. I hope Gamaleya resolves these issues and supports it with data and robust QC/QA.
PS-though I wish it were for different reasons, I’m always thankful for the opportunity to practice my Russian exclamations. Да ты что, Гамалея!
More info here: apparently the Ad5 vector was capable of forming plaques on A549 cells. The explanation is recombination, which begs the question: if it was manufactured using best practices, WTF did the vaccine vector recombine with?
h/t @hildabast
Could be either a wild-type AdV or a packaging vector. To make replication-deficient vaccine vectors, you have to grow the virus in a "packaging" cell line expressing E1 in trans (on a separate piece of DNA called a plasmid).
At this stage recombination could occur with E1 DNA from the packaging cell line, but usually there are QC measures in place to ensure this doesn't happen. Deleting E1/E3 in many Ad-vectored systems is also needed to make "room" in the genome for the insert, SARS-CoV-2, spike.
I don't know enough about the specific AdV system used here, but it's reasonable to think that if E1 recombined w/ the Ad vector, it might replace spike. So that's doubly bad: you not only have a replication-competent Ad5, it's not expressing spike. Which is...the entire point.
One thing is clear: if the vaccine were forming plaques on A549s, that means there's infectious, fully replication competent virus there. A plaque is a "hole" in a carpet (monolayer) of cells on a culture plate caused by cytopathic effect (virus killing cells).
The plaque assay is a classical virological technique used to titrate infectious virus. An individual cell killed by a virus can't be seen without a microscope. To see a plaque with the naked eye, the virus has to spread to surrounding cells, and to do that it has to replicate.
No visible plaque=no spread to surrounding cells=no viral replication.

So if they saw plaques on A549s (a type of lung cell that is convenient for plaquing adenoviruses), that means there was fully replication competent virus.

It's a basic and inexcusable failure of QC/QA.
Here's a GIF that presents an analogous situation of what the Anvisa regulators observed:

• • •

Missing some Tweet in this thread? You can try to force a refresh

Keep Current with Dr. Angela Rasmussen

Dr. Angela Rasmussen Profile picture

Stay in touch and get notified when new unrolls are available from this author!

Read all threads

This Thread may be Removed Anytime!


Twitter may remove this content at anytime! Save it as PDF for later use!

Try unrolling a thread yourself!

how to unroll video
  1. Follow @ThreadReaderApp to mention us!

  2. From a Twitter thread mention us with a keyword "unroll"
@threadreaderapp unroll

Practice here first or read more on our help page!

More from @angie_rasmussen

12 May
Fantastic thread & piece by @kakape on the peri-mortem analysis of the pandemic, the IPPPR report on COVID-19 led by @HelenClarkNZ & @MaEllenSirleaf.

This report addresses the key question: what went wrong & how can that be avoided next time (because there will be a next time)?
There were a lot of mistakes, most notably not recognizing pandemics as the urgent threats they are.

But here's the breakdown of the most significant missteps:
1. We ignored warnings that we were unprepared for a pandemic
2. Governments failed to adequately prepare
3. WHO was late in declaring a PHEIC (public health emergency of international concern)
Read 9 tweets
5 May
Public health people are often accused of "enjoying" the pandemic. Now some say that anxiety about reopening is actually "fear of normalcy."

Thanks @ChuckWendig for this perfect antidote to the stupid, unsympathetic idea of pandemic "addiction."
The past 15 months have been extremely traumatic to all of us, and not just because of "fear." Of course fear is one part of what's made this so awful, but there's also: loss, grief, isolation, etc. It's entirely cruel and unsympathetic to suggest anyone is "addicted" to trauma.
And many of the people preaching this addiction gospel also position themselves as optimists. One person even created a hashtag #FONO ("fear of returning to normal") to further pathologize a completely normal reaction to trauma and suggest may be a worse epidemic than COVID.
Read 8 tweets
4 May
Seeing a lot of explanations that attribute the horrific surge in India to one thing or another (variants, aerosols, vaccines, etc), all of which betray a facile understanding of how a crisis like this occurs.
"It's because of more transmissible variants!"

This might contribute, but as Dr. @ashishkjha points out, 40% of the population lives in multi-generational households. This is conducive to the spread of any variant, especially to older, higher risk people.
And for their contribution to the overall cases, more transmissible variants are a problem in the surge of severe cases that are overwhelming the inadequately funded health care system. The variants may cause more infection, but more people are dying b/c they can't access care.
Read 25 tweets
3 May
Last week the Sputnik V Twitter account said I was spreading "fake news" in this thread & that I read their statements and as-yet-unreleased correspondence with Anvisa, the Brazilian regulator, as proof.

Anvisa held a press conference. A minor correction is in order.
Let's just get the correction out of the way: Anvisa wasn't responsible for batch testing Sputnik V and didn't find plaques on A549 cells. That was Gamaleya, and they bent over backwards to claim that isn't what their data shows.

BUT IT DOES. Let me explain.
First, let's refresh:

Sputnik V is a viral-vectored vaccine. It uses a type of common cold virus called adenovirus to express the spike protein from SARS-CoV-2. The adenovirus vector is engineered to be replication-defective, meaning these viruses can't reproduce themselves.
Read 32 tweets
30 Apr
There's a lot of myths and misperceptions so I'll try to cover this quickly! See thread below:
1. Vaccines give you COVID. None of the currently authorized vaccines can give you COVID. They only use the SARS-CoV-2 spike protein, and there is no intact virus in any of the vaccines. Flu-like side effects aren't COVID...they are temporary and just show the vaccine is working!
2. mRNA vaccines are gene therapy. mRNA is chemically similar to DNA, but it is not the same thing. mRNA cannot alter DNA and never actually even gets into the part of the cell where DNA is stored (the nucleus). mRNA vaccines make spike protein for a day or two, then degrade.
Read 13 tweets
30 Apr
The vaccines are very safe! We knew this initially because of data from clinical trials, in which thousands of people were vaccinated and studied, as well as from observations of people who have been vaccinated since the vaccines came on the market. Some more detail below:
In the phase 3 trials for Pfizer, Moderna, and J&J there were a handful of severe adverse events reported out of more than 100,000 participants combined in those 3 trials. The most common (but still rare) safety concerns are with allergic reactions. Those are easily treatable.
Nearly 200 million doses of Pfizer and Moderna have been given in the US. There are no "safety signals" reported. "Safety signals" are reports of a severe illness that might be vaccine-related in a database at CDC called VAERS (Vaccine Adverse Event Reporting System).
Read 5 tweets

Did Thread Reader help you today?

Support us! We are indie developers!

This site is made by just two indie developers on a laptop doing marketing, support and development! Read more about the story.

Become a Premium Member ($3/month or $30/year) and get exclusive features!

Become Premium

Too expensive? Make a small donation by buying us coffee ($5) or help with server cost ($10)

Donate via Paypal Become our Patreon

Thank you for your support!

Follow Us on Twitter!