Dr. Ali Nouri Profile picture
Molecular Biologist; President, Federation of American Scientists; National Academy Science Diplomacy Roundtable; Fighting misinfo: https://t.co/LO4bkSV22c
So Into Italy My Blood is Rated DOCG🍝🇮🇹🇮🇹🍝 Profile picture Sue Strong 🇺🇸🇦🇺🇨🇦🇳🇿🇬🇧 #BidenHarris2020 Profile picture Narayan Subramanian Profile picture Karen Salitis Profile picture Aviva Gabriel Profile picture 22 added to My Authors
16 Jan
📌1/Infectious #SARSCoV2 in the air of a car 2 hrs after unmasked driver w/mild #COVID exited vehicle. Researchers found the virus in tiny air samples (0.25-0.5 um) and showed the virus retained ability to infect cells in a lab. H/T @UniversalMaski2 1/8🧵
rb.gy/odlbap ImageImage
2/In July study found the virus to be stable in air. Mechanically generated aerosols/airborne #SARSCoV2 retained ability to infect cells for at least 16 hrs. Hardier in aerosols than SARS-1 or MERS. Helps explain why #airborne route is a major culprit: rb.gy/jxh0oh 2/8 Image
3/#Airborne transmission has been observed in a restaurant from 20 ft away. How do they know? Video footage showed patient had no direct contact w/those who were infected far away. The restaurant lacked windows & ventilation system: rb.gy/5lh973 3/8 ImageImage
Read 8 tweets
7 Jan
1/📌Concerning case of reinfection: healthy 45 year old was reinfected with the genetically distinct SARS-CoV-2 variant that harbors the E484K mutation - this is the variant that was recently reported to escape neutralizing antibodies 1/6🧵 Image
2/Second infection was more severe. Given the infections were 5 months apart its hard to know whether the immune response against the 1st infection simply waned, or, alternatively, if the variant virus managed to evade the immune response 2/6
preprints.org/manuscript/202… Image
3/Mutation is in RBD region of virus - the part that grabs human cell surface receptor, ACE2. Antibodies that bind RBD can block virus from entering our cells. But an earlier report this week showed that the E484K mutation in RBD is reducing the ability of antibodies to bind. 3/6 Image
Read 7 tweets
5 Jan
1/📌BREAKING on #SARS_CoV_2 variants: the emerging variants in South Africa and Brazil that harbor the E484K mutation have "greatly reduced susceptibility" to neutralization by polyclonal serum antibodies derived from some individuals. This may have consequences for vaccines🧵
2/The "Receptor Binding Domain" on the Spike protein of the virus is a critical site for antibodies to bind to because those antibodies can block the virus from binding the ACE2 receptor on our cells. Mutations at that site are allowing the virus to escape antibodies.
3/Report shows neutralizing activity of convalescent sera (rich in polyclonal antibodies) was reduced >10-fold because of single mutation in RBD domain. They also found some sera samples that still neutralized, perhaps through antibodies binding other critical regions of spike.
Read 5 tweets
30 Dec 20
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🧵
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.
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.
Read 5 tweets
29 Dec 20
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🧵
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
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 20
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
Read 5 tweets
28 Dec 20
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 20
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 20
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 20
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
14 Dec 20
📌1/CDC Report on Vietnam's🇻🇳Incredible Tracing/Quarantine Program: after outbreak in major Hanoi Hospital, entire 7,664-persons staff quarantined. Contact tracing in the community resulted in an additional 52,239 people being quarantined. After 3 weeks, outbreak was contained🧵 Image
2/They didn't just quarantine close contacts of infected, but all hospital visitors & their close contacts (F2s) were provided quarantine support: room and board. Contacts of F2s (F3s) & Contacts of F3s (F4s) were even asked to self-isolate: wwwnc.cdc.gov/eid/article/27… Image
3/Aggressive tracing/quarantine in Vietnam isn't unique to this outbreak. As @findingsen writes, once case is identified, all contacts in prior week are identified and quarantined. Those individuals' contacts are identified and asked to self-isolate.
globalasia.org/v15no3/cover/v…: Image
Read 4 tweets
12 Dec 20
1/Suspected #SARSCoV2 reinfection in Peru🇵🇪: symptomatic 42yr old tested positive in June, but did not develop pneumonia (Row A👇). She improved, symptoms resolved. Then in October, she presented w/symptoms again, tested positive, this time had lung lesions w/pneumonia (Row B)🧵
2/case highlights there are far more reinfections than confirmed. Bar to establish reinfection is high: requires genetic sequencing of viruses to rule out single continuing infection but only small # of samples are sequenced/stored for future purposes like confirming reinfection.
3/For instance, at the GISAID international database of SARS-CoV-2 genetic sequences, there are only 385 virus🧬sequences from Peru, but the country has reported about 1 Million cases, so only 0.04% of cases have been sequenced.
Read 4 tweets
1 Dec 20
1/📌SARS-CoV-2 in aerosols: from dispersion in air, to inhalation and disease: (a) while large drops (green) are ballistically and fall, smaller ones (red) can remain buoyant; (b) Droplets evaporate to form aerosols, reducing to just biopolymers and virus particles🧵
2/Larger aerosols deposit in upper throat, nose, & tracheobronchial region of the lung. Medium-sized aerosols mostly deposit in small airways further down. The really small aerosols <1 μm can penetrate all the way to the alveoli - the basic units for gas exchange.
3/In contrast to other mode of transmission where virus hits nasal cavity and then finds its way into lungs, aerosols can directly reach alveolar region and attack alveolar cells that produce Pulmonary Surfactant. PS is needed to lower surface tension & prevent alveoli collapse
Read 5 tweets
29 Nov 20
1/📌COVID-19 neurological challenges: while respiratory problems receive most attention, nearly 10-35% survivors suffer disabling, persistent neurological symptoms. Patients w/altered mental health hospitalized 3X times longer; 2/3 unable to manage daily activities at discharge🧵
2/Underlying causes are complex. Low oxygen; metabolic irregularities. Inflammatory response in the brain—activation of microglia & cytotoxic T cells—and other signs of neuropathy have also been observed.
3/Loss of smell/taste: 40-60% of patients develop loss of smell; ~90% have alteration of smell. Many recover sense of smell, others have more severe cases, possibly permanent loss of smell. Virus invades cells in vicinity of olfactory nerve; unclear if it directly invades nerve
Read 4 tweets
23 Nov 20
1/The #AstraZeneca vaccine is a version of an adenovirus (common cold virus) that delivers instructions to our cells to make the Spike protein of the coronavirus. That way our immune system is "trained" so when it encounters #SARSCoV2, it can mount an efficient response🧵
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.
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.
Read 5 tweets
20 Nov 20
1. CDC: Postponing travel & staying home is the best way to protect yourself and others, especially if those you're visiting are at increased risk of getting very sick from COVID-19, like older adults & those with medical conditions. But there are plenty of other risks too🧵
2. Other factors that make your visit especially high risk are if cases in your community or the ones you're visiting are high. You can check that in CDC’s COVID Data Tracker here: bit.ly/392Dx0A. Many areas also have travel restrictions: bit.ly/3lQsUS1
3. You can also find out if hospitals in your community or your destination are overwhelmed with COVID-19 patients. That could make it a challenge to get the help you or others may need if you get sick. You can get that info by checking state & local public health dep. websites.
Read 7 tweets
11 Nov 20
📍CDC Guidance Update: Masks don't just reduce the amount of virus we release🗣️, masks also reduce the amount of virus we inhale😷. Here's a thread on some published🔬studies on the effectiveness of masks in cutting down #SARSCoV2 transmission🧵 Image
1. In a study of 124 Beijing households with confirmed cases of SARS-CoV-2 infection, mask use by the index patient and family contacts BEFORE the index patient developed symptoms reduced secondary transmission within the households by 79%.
pubmed.ncbi.nlm.nih.gov/32467353/
2. Two hair stylists who were COVID-19 positive spent at least 15 min with 139 clients. 67 clients who agreed to be tested were all negative and none of the other clients are known to be infected. Everyone was wearing masks 😷.
Report: bit.ly/2ZrjGD0 Image
Read 7 tweets
5 Nov 20
Does #SARSCoV2 increase risk of🧠Parkinson’s Disease (PD)? Recent reports documented PD onset following severe #COVID19 in a 35, 45, & 58 year old. They developed severe motor symptoms; brain imaging revealed reduced function of dopamine system, akin to PD🧵
2. Possible mechanisms include: (a) blood clots and other circulatory problems that occur in some COVID patients could reduce blood flow to brain and to dopamine system or (b) inflammation caused by severe COVID-19 could trigger neuroinflammation and demise of dopamine neurons.
3. Consistent with this, another study looked at brains of COVID19 patients post-mortem and found an inflammatory response response in their brains—the activation of microglia & cytotoxic T cells—which are neuropathological signs that are also associated with Parkison's Disease.
Read 5 tweets
2 Nov 20
#SARSCoV2 from transmission🗣️to disease🤒:

1. Spike protein on the virus binds the ACE2 receptor on human cells. The Virus RNA is released into the cell, where it is translated into proteins that assemble and make-up new virus particles that are then sent back out of the cell🧵
2. #SARSCoV2 comes out of the respiratory tract🗣️on small aerosols that stay airborne and are then inhaled; on bigger respiratory droplets💧that splash into others' nose/mouth/eyes or they land on surfaces and get picked up by touch; the virus is also excreted through human waste
3. #COVID affects many of the body's systems—upper and lower respiratory tract 🫁; heart🫀, where it can cause arrhythmias & other problems; digestive problems like nausea, pain, vomiting; neurological🧠problems where people suffer cognitive challenges even after recovery & more.
Read 5 tweets
5 Oct 20
Science magazine: We must shift our thinking and focus on Airborne transmission of SARS-CoV-2.

Inhalation is a major route. Viruses in large droplets fall to the ground in seconds within 2 m. Viruses in aerosols remain suspended for hours, like smoke, and are inhaled 1/4
Aerosols are highly concentrated near an infected person, but they can also travel more than 2 m and accumulate in poorly ventilated indoor air, leading to superspreading events. Even without symptoms thousands of virus-laden aerosols are released by breathing and talking 2/4
Thus, it's more likely to inhale aerosols than be sprayed by droplets so we must focus on airborne transmission. In addition to masks, distancing, hygiene, we need guidance to move activities outdoors, improve indoor air w/ventilation & filtration & protect high-risk workers 3/4
Read 4 tweets
29 Sep 20
NIH STUDY: 3 interventions had the most impact on COVID infections: closing schools, closing bars, wearing masks.

Here's Maryland where trajectory of case rate (green) hospitalizations (blue) and death (black) all change with a few days of lag time after closures🧵 1/n
Researchers also looked at school closure, alone. Here's Georgia where school closure occurred prior to closing bars and appears to cut the rate of infections (green) in half, beginning 8-14 days post-closure. Rates of hospitalizations (blue) & death (black) also went down (2/n)
Mask mandates also led to a drop in the rate of infections (green); drops in the rates of hospitalizations (blue); and deaths (black) "Mandating masks is to drop the slopes about 2 fold". Here's New Jersey (3/n)
Read 5 tweets