Covid-19: How it Spreads and How it can be Slowed

I know a family who went to New Zealand in late January for a 2-month vacation. They are still there; voluntarily. I asked about visas. They said their visas had been extended until September, because of Covid.
 
Greg Bockelman said:
That is all well and good but I would still like to know when we might be able to roam freely on the earth, so to say.
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I think that will be when we have effective vaccines in widespread distribution. (The vaccines are probably going to beat specific, effective therapeutics to the table by a wide margin. One of the best candidates, EIDD-2801 is a ways off from approval and is not exactly a "cure.") Good news is AstraZeneca is manufacturing the "Oxford" vaccine in anticipation of successful Phase 3 trials starting early July and is expecting to have 300 million doses available in the U.S. in October. If this pans out--no hiccups--that would mean some degree of personal protection would be available by December (assuming a two-dose regimen, one month apart, and 2-3 weeks to develop antibodies). The Moderna mRNA vaccine won't be too far behind, and I think it is also planned for anticipatory manufacture. It is looking likely it will be a two-dose vaccine as well based on Phase 1 trials, but Phase 2-3 trials may change that. Until then, some sort of mitigation measures (distancing, mask usage, avoidance of crowds, especially indoors) will have to be in place to keep transmission in check. We WILL turn the corner on this, but it will take a little more time yet for science to proceed. Meanwhile, we will likely be inconvenienced. I'm still trying to figure out with a board how and when to open up a sports facility and keep our members, a large fraction of which are in a higher risk age category, reasonably safe.
 
Everskyward said:
I know a family who went to New Zealand in late January for a 2-month vacation. They are still there; voluntarily. I asked about visas. They said their visas had been extended until September, because of Covid.
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When I grew up in germany, our local baker went on a two week vacation to NZ and never returned. A local business filed whatever paperwork he needed for a work visa and then landed immigrant status.
I saw something similar with a local ophthalmologist in the US. 2 week vacation turned into 4 weeks and the next thing she sold the practice to her associate.

Not sure what the drug is they put in your drinks, but the place has a way to get a hold on folks.
 
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Bob Noel said:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7108646/

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2440799/

conclusions might surprise some people.
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There are a lot of factors which could potentially help or hinder the efficacy of cloth mask usage by the general public. There are over 100 publications on this subject now. So for non-professionals not wanting to read all that, I recommend looking at the 4 reviews presently in pre-print form as well as the discussion in the BMJ on these factors.

I placed links to these on my medical page today after giving a talk. Available at http://steinmetz.org/peter/Medical/index.html .

Overall about a 50/50 mix of whether a good or bad idea. In my talk I said definitely an area where reasonable people and scientists might disagree.
 
steingar said:
Not all masks are created equal.
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Truth.....N95 are much more efficient than cotton flaps. An N95 with a surgical is much more efficient than just a surgical mask. And if trained medical staff is donning the masks they are even more efficient. ;)
 
steingar said:
Not all masks are created equal.
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And not all mask usage is equal. I’ve seen some real bizarre utilization of masks since we started mandatory use.

I see a ton of people wearing masks over their mouth, but their nose is fully exposed.

And then there are the real geniuses: I watched a student the other day in the sim pull his mask down in order to sneeze! I’m like “you’re doing it wrong!”
 
Fearless Tower said:
And not all mask usage is equal. I’ve seen some real bizarre utilization of masks since we started mandatory use.

I see a ton of people wearing masks over their mouth, but their nose is fully exposed.

And then there are the real geniuses: I watched a student the other day in the sim pull his mask down in order to sneeze! I’m like “you’re doing it wrong!”
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Depends on whether he is wearing it to protect him or you.

Pop quiz on that topic. Does the filter on a N95 mask filter inhaled or exhaled breath?
 
Salty said:
Pop quiz on that topic. Does the filter on a N95 mask filter inhaled or exhaled breath?
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(without using google) I believe the specification is related to protecting the person wearing the mask.
 
Salty said:
Depends on whether he is wearing it to protect him or you.

Pop quiz on that topic. Does the filter on a N95 mask filter inhaled or exhaled breath?
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Both, to some extent, though many have a one-way flapper valve on the front that opens on exhalation, and closes on inhalation, so those filter fully on inhalation and better protect the wearer.
 
Doc Holliday said:
https://justthenews.com/politics-po...g-new-deaths-flat-younger-patients-recovering
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lmao. I love cherry picked news articles.
Death rates have lagged behind case numbers since this started. the lag is roughly 30 days, and is a very noisy metric. As such, you really need multiple days to determine trend line changes.

But on one point, the article is correct. The influx of younger people getting COVID-19, especially in Texas, will push down the fatality rate of confirmed cases based on total population (well known and previously established that younger people have a lower fatality rate; this is not breathless news you know).

Tim
 
tspear said:
lmao. I love cherry picked news articles.
Death rates have lagged behind case numbers since this started. the lag is roughly 30 days, and is a very noisy metric. As such, you really need multiple days to determine trend line changes.
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the worldometer metrics show a definite pattern... over the weekend there are fewer deaths reports, with elevated counts on Monday/Tuesday...Thus, a 7-day moving average isn't a bad thing to look at.
 
chemgeek said:
I think that will be when we have effective vaccines in widespread distribution. (The vaccines are probably going to beat specific, effective therapeutics to the table by a wide margin. One of the best candidates, EIDD-2801 is a ways off from approval and is not exactly a "cure.") Good news is AstraZeneca is manufacturing the "Oxford" vaccine in anticipation of successful Phase 3 trials starting early July and is expecting to have 300 million doses available in the U.S. in October. If this pans out--no hiccups--that would mean some degree of personal protection would be available by December (assuming a two-dose regimen, one month apart, and 2-3 weeks to develop antibodies). The Moderna mRNA vaccine won't be too far behind, and I think it is also planned for anticipatory manufacture. It is looking likely it will be a two-dose vaccine as well based on Phase 1 trials, but Phase 2-3 trials may change that. Until then, some sort of mitigation measures (distancing, mask usage, avoidance of crowds, especially indoors) will have to be in place to keep transmission in check. We WILL turn the corner on this, but it will take a little more time yet for science to proceed. Meanwhile, we will likely be inconvenienced. I'm still trying to figure out with a board how and when to open up a sports facility and keep our members, a large fraction of which are in a higher risk age category, reasonably safe.
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The Oxford vaccine is a bust. See https://www.forbes.com/sites/willia...cine-work-in-monkeys-not-really/#3c54f8813c71
 
I’ve never trusted nucleic acid based vaccines. They’re based on gene therapy technology, which I’ve never felt lived up to their promise. I think a subunit vaccine akin to the HPV vaccine will win the day.
 
bdtaz said:
Reading the article, it is "bust" as far as providing true immunity but has promise with regards to minimizing the impact of getting infected.

Better that nothing, especially for those in a high risk group.
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A bad year to be a Rhesus monkey....

We may end up with different vaccines for different groups. This candidate sounds like it may limit the virus ability to cause pneumonia, and that is still the main mechanism for morbidity and mortality.
The flu vaccine is'nt 100%, neither is the pneumococcal vaccine. Still, they are worthwhile in the management of the respective diseases
 
Datadriver said:
The Oxford vaccine is a bust. See https://www.forbes.com/sites/willia...cine-work-in-monkeys-not-really/#3c54f8813c71
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We won't know if it's a "bust" until the Phase 2/3 human trials are done. That's what they are designed to determine. The key piece is the generation of neutralizing antibodies. The technology used (the genetically modified ChAdY25 chimpanzee viral vector) has been previously used to deliver genetic payloads for immunization, so it is not a brand-new system. And humans should not have significant immunity to the viral vector, which does not circulate in human populations. This is in contrast to the Sinovac vaccine, which uses a human Ad5 vector to deliver its payload. Unfortunately, many individuals harbor antibodies to the Ad5 virus, limiting its efficacy in those individuals.
 
steingar said:
I’ve never trusted nucleic acid based vaccines. They’re based on gene therapy technology, which I’ve never felt lived up to their promise. I think a subunit vaccine akin to the HPV vaccine will win the day.
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There have been no mRNA vaccines brought to market to date. The Moderna COVID-19 vaccine would be the first, I think. (An mRNA vaccine for MERS was developed but never brought to market because the virus died out.) This technology has a significant advantage in terms of simple and rapid manufacture. Efficacy will be determined by Phase 2/3 trials to begin shortly. I think this is the technology of the future, as it has rapid response and immense flexiblity, as well as ease of manufacture by automation.

I think you are confusing mRNA vaccines with viral vector systems, which were not so happy for gene therapy, but have found utility as vaccine delivery vehicles. Several of these viral vectors are being used to develop Covid-19 vaccines, including ChAdY25 ("Oxford" vaccine, based on a genetically modified chimpaznee adenovirus), Ad5 (Sinovac and others, using a genetically modified human adenovirus), and vesicular stomatitis virus (VSV, used to develop the Ebola vaccine). Each of these systems has its pros and cons.

There are also manufacturers using more traditional approaches, such as recombinant proteins with adjuvants (like Shingrix) and good old-fashioned killed whole virus (Wuhan Laboratories). That last one may be the first out of the blocks worldwide, but is much more difficult to manufacture.

One of more of these systems is going to provide personal protection, which could vary from complete immunity (for some period) to modifying disease course to be less serious.
 
chemgeek said:
There have been no mRNA vaccines brought to market to date. The Moderna COVID-19 vaccine would be the first, I think. (An mRNA vaccine for MERS was developed but never brought to market because the virus died out.) This technology has a significant advantage in terms of simple and rapid manufacture. Efficacy will be determined by Phase 2/3 trials to begin shortly. I think this is the technology of the future, as it has rapid response and immense flexiblity, as well as ease of manufacture by automation.

I think you are confusing mRNA vaccines with viral vector systems, which were not so happy for gene therapy, but have found utility as vaccine delivery vehicles. Several of these viral vectors are being used to develop Covid-19 vaccines, including ChAdY25 ("Oxford" vaccine, based on a genetically modified chimpaznee adenovirus), Ad5 (Sinovac and others, using a genetically modified human adenovirus), and vesicular stomatitis virus (VSV, used to develop the Ebola vaccine). Each of these systems has its pros and cons.

There are also manufacturers using more traditional approaches, such as recombinant proteins with adjuvants (like Shingrix) and good old-fashioned killed whole virus (Wuhan Laboratories). That last one may be the first out of the blocks worldwide, but is much more difficult to manufacture.

One of more of these systems is going to provide personal protection, which could vary from complete immunity (for some period) to modifying disease course to be less serious.
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My problem with the nucleic acid vectors is we've evolved for millions of years to defend ourselves against viruses, and now we think we can just use them to introduce whatever we want because we known everything about them. Pure arrogance on our part.
 
Palmpilot said:
One doctor's summary of why face masks help, even home-made ones, with links to the evidence.

Excerpt:

"I’m not here to force you to wear a mask, or to call you stupid for not wearing one. I’m just here to show you the evidence that changed my mind. I hope you come to the same conclusion as I did: We don’t have to choose between killing the economy or killing people. With simple face masks in addition to hand washing we can eliminate the virus, reopen the economy, and save thousands of lives all at the same time."​

https://www.facebook.com/james.larson.md/posts/10221384253946100

(Yes, I know it's Facebook, but I take the view that whether a writer knows what he's talking about and presents supporting evidence are far more important than which communications medium he chooses.)

Edit: For reasons that make no sense to me, Facebook took down the post linked above. Fortunately, the author also posted it to his blog:

https://larsonsportsortho.com/are-masks-effective-against-the-coronavirus-disease/

He says that he will also be posting a new version with updated research on his Facebook page:

https://www.facebook.com/james.larson.md
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The link to Doctor Larson's review of the evidence on face masks is broken, so I added a new link in the post above.
 
steingar said:
I’ve never trusted nucleic acid based vaccines. They’re based on gene therapy technology, which I’ve never felt lived up to their promise. I think a subunit vaccine akin to the HPV vaccine will win the day.
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bbchien said:
My bet as well....
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You guys want to explain that in basic English?
 
Greg Bockelman said:
You guys want to explain that in basic English?
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Most vaccines use a weakened or killed virus. Our immune system sees the virus and mounts and immune response, but we don't get the illness because the virus can't replicate efficiently. These sorts of vaccines work very well, but are difficult to produce and have risk. If the virus isn't dead or weakened the vaccine itself can cause disease. And virus has to be replicated in the laboratory to make such vaccines. Most of the vaccinations you or your children have received are of this type.

There is a second sort of vaccine coming on the scene called a subunit vaccine. Human Papilloma Virus (HPV) is a good example. They took a coat protein of HPV (one of the proteins on the surface of the virus) and produced it in yeast. It is then used as an inoculant to drive an immune response against the virus coat protein. The reason they used yeast is they're really cheap, they're really just jumped up bacteria. The HPV vaccine is one of the most effective I've ever seen, if you have your preteen daughters vaccinated they won't get the virus nor will they get the cervical cancer it causes. There are several subunit vaccines in the works for the 'rona. A number of these use human cells to produce the protein antigens (and antigen is a substance that causes an immune response) so they're likely to generate some controversy.

The last kind of virus is called an mRNA virus. The idea is to introduce the genetic information for viral antigens to cells, allow them to make the proteins, and have the proteins initiate an immune response. The idea is to inject an mRNA, the protein production instructions normally encoded by DNA. There exist ways to strengthen mRNAs (which are normally quickly degraded) and deliver them. Cells don't have to make much protein to illicit an immune response. The advantage is that an mRNA vaccine can be made much more quickly and inexpensively than any other (which is why mRNA vaccines are so far ahead of all the others). The disadvantage is they've never ever worked even once. There are serious technical challenges to delivering mRNA to cells in vivo, which is basically gene therapy.
 
well....the new mRNA vaccines are producing antibodies......wonder if they'll produce T-cell immunity?
 
steingar said:
They've been working on mRNA vaccines for 30 years and they haven't worked even once in humans.
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well....they are progressing thru stage 2 and gearing up for stage 3 testing......just say'n. ;)

....and what do I know about medical science? :D
 
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