Kyle Allred
MedCram
Kyle Allred is a physician assistant and a co-founder of MedCram. His published work includes a clinical case study in family practice regarding the diagnosis of arm spasms and twitches experienced upon throwing.
4 claims checked on air: 3 supported 1 unverified
What they said on air
Studies from Israel and the US found that a high percentage of patients under 50 presenting to the emergency room with strokes had active or prior SARS-CoV-2 infections that they were previously unaware of.
"there was this study, multiple studies, one out of Israel and a couple out of the United States, showing that people under the age of 50 were coming into the emergency room for strokes. And one of the studies out of Israel found, because they test everyone for COVID-19, you know, a great deal of the like a high percentage of the people that were coming in for these strokes, these young people under 50, had COVID-19 and didn't even know they had had it." (said at 0:15:06)
No published record matching the claim—that studies from Israel and the United States demonstrated a high percentage of patients under age 50 presenting to the emergency department with strokes had previously unrecognized SARS-CoV-2 infections—was located; this does not prove the claim false.
There are approximately 26 spike proteins situated on the surface of a single SARS-CoV-2 viral particle.
"There are about 26 different spike proteins—I shouldn't say different, there are about 26 spike proteins that line the surface of a SARS-CoV-2 viral particle." (said at 0:20:18)
Structural biology investigations of intact SARS-CoV-2 virions using cryo-electron microscopy and cryo-electron tomography (cryo-ET) show that each viral particle displays an average of approximately 24 to 26 spike (S) protein trimers on its surface, with virions exhibiting variable spike densities ranging typically from around 10 to 40 spikes.
All COVID-19 vaccines authorized in the US (Moderna, Pfizer-BioNTech, Johnson & Johnson, and Novavax) incorporate two proline substitutions (2P) to stabilize the spike protein in its pre-fusion conformation.
"all of the vaccines that are available in the United States under either emergency use authorization or under FDA authorization or up-and-coming vaccines, so that includes the Moderna and the Pfizer-BioNTech mRNA vaccines, the Johnson & Johnson adenoviral vaccine, as well as the Novavax vaccine, they all contain an insertion of two proline amino acids into the spike protein to lock it into the pre-fusion conformation." (said at 0:22:34)
The primary COVID-19 vaccines authorized and used in the United States (Moderna mRNA-1273, Pfizer-BioNTech BNT162b2, Johnson & Johnson/Janssen Ad26.COV2.S, and Novavax NVX-CoV2373) incorporate structure-based engineering consisting of two consecutive proline substitutions (known as the 2P mutation, at positions K986 and V987) at the top of the central helix. These substitutions prevent the structural rearrangement required for membrane fusion, maintaining the spike glycoprotein in its metastable, highly immunogenic prefusion trimer conformation to elicit effective neutralizing antibody responses.
- supports: SARS-CoV-2 S Glycoprotein Stabilization Strategies. (Viruses 2023) · cited 8x in the literature
"Like all enveloped virus glycoproteins, SARS-CoV-2 S native prefusion trimers are in a metastable conformation, which primes the glycoprotein for the entry process via membrane fusion. S-mediated entry is associated with major conformational changes in S, which can expose many off-target epitopes that deviate vaccination approaches from the major aim of inducing neutralizing antibodies, which mainly target the native prefusion trimer conformation. Here, we review the viral glycoprotein stabilization methods developed prior to SARS-CoV-2, and applied to SARS-CoV-2 S, in order to stabilize S in the prefusion conformation." (abstract, results, passage verified)
pubmedfull study (doi)
Structural biologist Dr. Jason McLellan engineered two-proline mutations to lock viral surface proteins into the pre-fusion conformation initially for Respiratory Syncytial Virus (RSV) and subsequently for MERS-CoV.
"And this was brilliant work done by the structural biologist Dr. Jason McLellan. He's at the University of Texas at Austin, and he thankfully had figured out this way to lock viral proteins into the pre-fusion conformation. First it was with the respiratory syncytial virus, RSV, and then later he had figured out for the other coronavirus, beta-coronavirus, the MERS coronavirus" (said at 0:23:04)
Published structural biology research confirms that Dr. Jason McLellan and colleagues pioneered structure-based methods to lock metastable viral fusion glycoproteins into their prefusion conformation. This work was first demonstrated for the respiratory syncytial virus (RSV) fusion (F) glycoprotein using engineered disulfide bonds and cavity-filling mutations (DS-Cav1), and subsequently extended to betacoronaviruses, including MERS-CoV and SARS-CoV, through engineered proline substitutions (such as the 2P mutation strategy).
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