1/📌In order to limit the importation of the variant coronavirus from the UK, CDC now requires travelers to be tested before boarding a flight. The strategy is insufficient because it's overly reliant on diagnostic tests that can't detect the virus in early stages of infection🧵
2/CDC requires a negative test up to 3 days prior to flight. One problem is you can test negative but catch the virus in intervening days. Another is that tests, even the gold standard PCR test, misses the virus in the early stages of infection & provides a false sense of safety.
3/This study, for instance, shows that on the day of the infection, the PCR test misses 100% of the cases. Each day after that the detection rate improves, but even by Day 5, when viral load tends to be high, these tests miss over a third of infections: bit.ly/2Hykuzk
4/This was one of the reasons behind the super spreading event at the White House. People were tested, thought it was safe, and walked into disaster. These tests are designed to confirm infections, not to rule them out.
5/In addition to tests, we should require quarantines for travelers, and not just those from the UK. These variants are in other countries too. Some countries we know about, some we don't yet know about. And we need to get serious about eliminating Covid here at home #ZeroCovid

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More from @AliNouriPhD

30 Dec
1/The #oxfordvaccine just approved in the UK is a version of an adenovirus (common cold virus) that instructs our cells to make the Spike protein of coronavirus. This trains our immune system so when we encounter #SARSCoV2, we can mount a defense. Here's how the vaccine works🧵 Image
2/#SARSCoV2 is covered w/Spike proteins that help the virus grab human cells. To make the vaccine, researchers first isolated the gene that is responsible for making the Spike protein. They 'snipped' it from the rest of the genetic material of the coronavirus. Image
3/They then needed a delivery vehicle to get the Spike gene into our cells. So they took an adenovirus that normally infects chimpanzees, and genetically altered it so it can no longer replicate or cause disease. They then added the Spike gene to the adenovirus vector. Image
Read 5 tweets
29 Dec
1/📌NIH Study: COVID-19 severity could depend on route of infection: Infection through inhaling #Airborne virus could lead to more severe disease than infection from fomites (contact w/ contaminated objects.) To test it, hamsters were infected via the different routes. 1/7🧵 Image
2/Intranasal (I.N) and aerosol inoculation caused more severe respiratory pathology, higher viral loads and increased weight loss. Fomite exposure led to milder disease. Here's weight loss👇Black lines are control animals in each group. 2/7 Image
3/Also, compared to intranasal exposure, aerosol exposed
hamsters had higher viral load in trachea and lung "suggesting aerosol exposure more efficiently deposits viral droplet nuclei in the lower respiratory system" Preprint: 3/7
biorxiv.org/content/10.110…
Read 7 tweets
28 Dec
1/📌Next US Vaccine💉:@Novavax began Phase 3 Trial. KEY difference: While Moderna/Pfizer deliver genetic material (mRNA) that our cells subsequently turn into Spike protein, #Novavax delivers the Spike protein directly. To do that, they first have to make Spike protein in a lab🧵
2/That's done by taking the Spike DNA🧬and splicing it into a larger piece of DNA that is used to deliver genes into cells that are growing in a lab. Those cells "read" the DNA, turn it into RNA, and then into proteins. The Spike proteins are then harvested and purified.
3/Next, Spike proteins are mixed with the delivery vehicle: synthetic particles, or "nanoparticles" that are about the size of the virus. Nanoparticles get studded with a bunch of Spike proteins. Those Spike proteins train and boost our immune system. rb.gy/i1lnb9
Read 6 tweets
24 Dec
1/📌Evidence of #Airborne #SARSCoV2 traveling 12 floors of an apt building through the drainage system: 200+ residents in a wing of a high-rise were tested, revealing 9 infections. Those families lived in 3 vertically aligned flats connected by drainage pipes in the bathrooms🧵 Image
2/To confirm apt units are indeed connected, tracer gas was released into drainage system of one unit and shown to come out of the other. Evidence for alternative mechanisms of transmission (e.g. use of public spaces, elevators, etc..) could not be found. Image
3/Plausible scenario is infection through drainage system. While U-traps typically act as water seals in each bathroom's drainage system, if unused, they can dry out, allowing aerosols from one unit to travel to another.
Report: ncbi.nlm.nih.gov/pmc/articles/P… ImageImage
Read 4 tweets
20 Dec
1/📌The UK #SARSCoV2 variant reported to be 70% more transmissible harbors a set of mutations in the Spike protein––the part of the virus that touches the human ACE2 receptor and allows the virus entry into our cells. One mutation, N501Y, allows Spike to bind ACE2 more tightly🧵
2/Another mutation, P681H, is near Spike's "Furin cleavage site" Unclear what the mutation does, but the location is significant because it's where enzymes "process" Spike, helping virus infect airway cells & enable efficient human-to-human transmission: rb.gy/sp0p34
3/these mutations are accumulating in the backdrop of another mutation, D614G, which has become dominant, globally, and has enhanced infectivity and replication fitness. It's even been shown, experimentally, to transmit faster through droplets & aerosols in hamsters.
Read 5 tweets
17 Dec
1/Great to be on @Mitch_Seattle to discuss the difference between the Pfizer, Moderna, and other vaccines💉and why we need high coverage in order to stop the chain of transmission🧵
2/The #Moderna vaccine, just like Pfizer/BioNTech, is a messenger RNA vaccine. #SARSCoV2 is covered w/Spike proteins that it grabs human cells with. The vaccine consists of small genetic material "messenger RNA" that instructs the human cell to make a part of the Spike protein
3/The mRNA is encased in a formulation of fatty material that helps it get inside our cells. There, it's "translated" into a piece of the Spike protein which activates our immune system to make antibodies & T cells so when we're exposed to the live virus, we can clear it.
Read 9 tweets

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