I understood his "yes" as indicating agreement with my statement that we don't yet know.
COVID, immunity and vaccines (no politics, science question)
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one data point here:
https://uahs.arizona.edu/news/uariz...ars-cov-2-antibodies-provide-lasting-immunity
“The latest time-points we tracked in infected individuals were past seven months, so that is the longest period of time we can confirm immunity lasts,” Dr. Bhattacharya said. “That said, we know that people who were infected with the first SARS coronavirus, which is the most similar virus to SARS-CoV-2, are still seeing immunity 17 years after infection. If SARS-CoV-2 is anything like the first one, we expect antibodies to last at least two years, and it would be unlikely for anything much shorter.”
While that may be true for a “Normal” Phase III Trial, The Moderna Trial that I’m in specifically included Geezers like me as well as others with the so-called underlying conditions as did the Pfizer version IIRC. I’m 79 and have had bypass surgery for example. So the elderly and less healthy were definitely included in the efficacy portion.
Cheers
GaryM
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Gary M
They did indeed include participants with risk factors other than age in the trials. From the Moderna FDA briefing document (https://www.fda.gov/media/144434/download)
"At least one protocol-defined high-risk condition for severe COVID-19 was present in 22.3% of participants, and 4% of participants had two or more high risk conditions. The protocol-specified risk factors were those conditions that placed an individual at increased risk for severe complications of COVID-19 and were selected based on CDC recommendations12 from March 2020. These conditions included the following:
Chronic lung disease (e.g., emphysema and chronic bronchitis), idiopathic pulmonary fibrosis and cystic fibrosis) or moderate to severe asthma
Significant cardiac disease (e.g., heart failure, coronary artery disease, congenital heart disease, cardiomyopathies, and pulmonary hypertension)
Severe obesity (body mass index ≥40 kg/m2)
Diabetes (Type 1, Type 2 or gestational)
Liver disease
HIV infection"
And from the document summary on page 43:
"Non-fatal Serious Adverse Events
Among participants who received at least one dose of vaccine or placebo (N=30,351), the proportion of participants who reported at least one SAE from dose 1 to the primary analysis cutoff date (November 25, 2020) was 1% in the mRNA-1273 group and 1% in the placebo group."
That 'yes' was to be understood as 'correct, we don't know that answer yet'.
The current vaccines were tested to an endpoint of 'developing clinical signs of covid infection'. As neither moderna nor pfizer was PCR testing their subjects every week, we dont know whether the vaccines stop the body from:
A. reproducing sars-cov2 virus in a way that can be detected with a respioratory tract swab in absence of clinical symptoms (i.e. asymptomatic infection)
B. producing enough sars-cov2 virus to still render a person infectious to others.
As the phase III trials did include antibody studies, we may get an answer to question A (it was a secondary endpoint in at least one of the trials). If individuals develop antibodies to sars-cov2 native components during the trial, they must have had the infection somewhere along the way without developing symptoms.
The only way to know whether the vaccine 'sterilized' the study subjects, one would need to collect information on the people around the study subjects. Neither of the studies included that data collection in their design. Given how ubiquitous the virus was during the time when the trials were conducted, it would be difficult to make a distinction if 'spouse B' got the virus from 'study subject B' or whether both were infected independently. Most of the case investigation data during a epidemic is gathered early on when there is no pre-existing infection in a population and you can tied together A got it from B who was in the break-room with C etc.
We will be able to tell to what extent the vaccine affects transmission once we have larger populations that have been immunized. 3 weeks in, Israel is at 12% of their population vaccinated with dose #1, so they'll get to a point when you can see whether there are secondary infections after someone got immunized pretty quickly.
It would be more accurate to say that those old samples showed some T-cell reactivity to SARS-Cov2. Whatever pre-existing immunity we have in the population is already baked into the numbers we are seeing right now. This infected 80-85% in some constrained ship-board populations, so either those sailors/fish-processors/chicken-pluckers are somehow different from the general population, or that t-cell reactivity is not conferring full immunity (pre-existing partial immunity may explain why one healthy 50 year old has the sniffles while another is in multi-organ failure in the ICU, but I haven't seen any convincing data to link the two).
Do you guys think countries will accept a Covid vaccine in lieu of being tested negative before arrival? I’m going to Croatia for my honeymoon and they require a negative PCR test within 48 hours which is sometimes hard to come by in NY. My fiancé is a police officer so she and myself would probably qualify for the vaccine sooner rather than later due to being essential workers.
chemgeek
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Yes, this is possible until there is more data on human transmission from vaccinated individuals. However, published preclinical viral challenge studies with both Pfizer and Moderna vaccines in non-human primates showed that nasal viral titers were essentially suppressed in the experimental group. So that is promising. These were very small studies, however, like a half-dozen macaques each. The same result was not the case for the AstraZeneca vaccine. Hence, the cautious approach to declaring that COVID vaccines will achieve herd immunity necessary to end viral spread.
chemgeek
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The FDA published specificity and sensitivity data for a variety of serology tests as a part of the EUA for their use. The practical usefulness of these tests depends significantly upon the true incidence of COVID-19 in the tested population. For reference, the national positivity rate is now between 5-10% but varies greatly among local communities. If you know the sensitivity and specificity numbers, you can predict how much a particular serology test will over- or under-estimate true incidence in the community for a given positivity rate. I've created a spreadsheet to do this type of evaluation. These types of tests are more problematic at lower incidence levels, when false positive may outnumber true positives. The TLDR version is that most of these tests are pretty good at estimating population incidence at incidence rates over 5%. Much below that, not so much. On an individual basis, you still have to deal with significant false negative rates, typically. Usually a positive means you are positive, but a negative is more iffy.
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SoonerAviator
No. The policy will want a document that says you don't currently have COVID. They don't care whether or not you have had the vaccine. The front-line workers won't have the authority (nor the desire) to bend the rules to allow a vaccination record in lieu of a negative Covid-19 test.
chemgeek
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FYI, these threads have been characterized by some really good questions. I hear the same things in my local community. I wish more university and college faculty would spend some time helping their communities understand the issues as the scientists understand them, and as scientific knowledge of the issues evolves with more data. I created local web site for my community where they can see current national and local data and trends, and some very basic educational material about vaccine technology, testing and status, immunity, and meaning of various statistics. (I'm retired, so I have a little time.) This is a service I would have hoped my former colleagues at the university would take up, but alas I suspect they are buried under remote teaching responsibilities, which is a nightmare to manage.
Everskyward
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Everskyward
Congratulations!
As far as what countries are going to require, I have no idea, although I suspect that each country will have their own requirements... which will evolve. I've traveled in Africa, and some countries require a yellow fever vaccine, with proof on a yellow card. They check it at immigration.
Yea I had to get the yellow fever vaccine for Delta. I wouldn’t be surprised if a Covid vaccine card will be required for entry.
PeterNSteinmetz
Ejection Handle Pulled
In terms of the immunity numbers, according to the SIR (Susceptible-Infected-Recovered) model of disease spread, the herd immunity threshold is given by (R0-1)/R0, where R0 is the base theoretical reproduction rate of the illness. See https://academic.oup.com/cid/article/52/7/911/299077.
It is thought that R0 for Covid-19 may be on the order of 4, so that would correspond to 0.75. A higher R0 of 8 would correspond to 7/8 or 0.875. A substantial increase, but not as bad as measles with an R0 of around 16.
There are more sophisticated models, but a simple way to think about the effect of a vaccine is to reduce the population of susceptible (S) individuals and they can directly contribute to the 0.75 or 0.85 of (R) that are needed to achieve herd immunity. So a less effective vaccine just takes fewer people into the 'recovered' category in this model and would thus require more to be infected and achieve natural immunity.
One thing that I never truly understood is the “risk factors”. If they have been treated and are now not a
“risk”, are the still a risk factor? For example, hypertension, diabetes, high cholesterol are all amenable to treatment with drugs and/or diet to bring things into a normal range.
Cheers
“risk”, are the still a risk factor? For example, hypertension, diabetes, high cholesterol are all amenable to treatment with drugs and/or diet to bring things into a normal range.
Cheers
PeterNSteinmetz
Ejection Handle Pulled
Likely depends on the particular risk factor. These you mentioned often result in some non-recoverable tissue damage before they are brought under control which might still leave a person more susceptible to Covid-19.
For example, hypertension can damage vessels and so even when the pressure is brought down, damage can remain.
OTOH, one of the larger risk factors for Covid-19 death is obesity. Losing weight will reduce that substantially.
tspear
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Timothy
I am talking way past my knowledge base.
However, from what I have read, and news programs, the mRNA vaccines actually replicate a smaller subset of the proteins in the virus then traditional vaccines using a "weakened live" virus or a dead version, in Moderna/Pfizer cases they specifically went after spike portion of the virus. The result is a more "narrow" range of antibodies are created to combat the virus, since there is a smaller "surface" area. What effect this has is at this point unknown, with some hypothesis showing that the human body reacts faster (due to a smaller surface area), but having a shorter memory since like many other small virus. Another hypothesis shows multiple exposures would increase long term memory, and exposure to the virus after receiving the vaccine will further re-enforce the memory making it last longer....
At least, that is what I picked up! Hopefully, someone with more knowledge can answer it.
Tim
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GeorgeC
Just got back from the Trial site. As I believed, I did receive the actual Vaccine back in Sept. Other than the injection site reaction, the first reaction being very mild and the second being more painful but gone in two days, nothing else.
No illness, no symptoms, no third eye in my forehead, no limbs falling off, no purple aura.
After the unblinding today, I’ll still be in the Trial. They will track everyone who wants to remain tracked for the duration including those who originally received the Placebo and regardless if they choose to be Vaccinated or not.
Cheers
No illness, no symptoms, no third eye in my forehead, no limbs falling off, no purple aura.
After the unblinding today, I’ll still be in the Trial. They will track everyone who wants to remain tracked for the duration including those who originally received the Placebo and regardless if they choose to be Vaccinated or not.
Cheers
Cool, so you're a "Typhoid Mary" now.
chemgeek
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It's even more complicated than this. There are dozens of strains of influenza characterized by different hemagglutinins and neuraminidase variants (The "H" and "N" in the identifier, e.g. H1N1). These strains are significantly distinct immunilogically. It is impractical to construct a vaccine with dozens and dozens of specific viral strains, so epidemiologists survey outbreaks to determine which 3-4 strains are most likely to circulate in the upcoming flu season and put that in the seasonal vaccine. SARS-CoV-2 is different, there is only one immunilogically distinct strain, at least for now.
FYI, there is "universal" influenza vaccine now in Phase 3 trials. This vaccine targets parts of the influenza virus that do not vary among the various HN strains. This could greatly enhance efficacy of influenza vaccine protection.
chemgeek
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Phase 1-3 trials did indeed evaluate immune response in older participants. While Phase 1 and 2 trials are limited to healthy individuals, Phase 3 trials include participants that are representative of the general population in terms of ethnicity, gender, age, and health conditions. The Pfizer Phase 3 trial, in which I enrolled, recruited participants from ages 18-85, and recently expanded their trial to include those from 12-17 as well as certain immunocompromised individuals (HIV and hepatitis C patients). Bothe the Moderna and Pfizer Phase 1 trials included volunteers over 65, and immune response data was evaluated separately for those under/over 65 to specifically evaluate both adverse effects and antibody/T-cell responses at various dosing levels. As expected, the published results show that immune responses for the 65+ cohort is slightly less than in the under-65 cohort, but still robust. The two-dose regimen is especially important in the older cohort in order to develop a strong immune response. There was a wealth of additional data shared as a part of the FDA review from the Phase 3 trials, which are not yet published.
denverpilot
Tied Down
As someone else mentioned, may depend on damage previously caused by any particular disorder.
Can also depend on drugs being used to treat the disorder.
People with my particular disorder were initially thought to be high risk due our disorder’s affinity for damaging lungs.
Reality has shown that since nearly all of us are on drugs to modify the immune reactions we all already have, for life, those same drugs have been effectively stopping the intense immune reaction (at different efficacy depending on drug used) of Covid across our (admittedly tiny) patient group as a general rule.
Our severe reaction, organ damage, and death numbers from Covid are statistically significantly lower than the averages.
But it’s mostly anecdotal right now, not because it isn’t happening — but because we as a group aren’t anybody’s priority for a real peer-reviewed study — and there probably won’t be anybody publishing or working on it either. No money to be made on our group — which is generally why it gets little research funding even in normal times.
(One Doc who is a worldwide specialist on the neuro version of the disorder relates in seminars that he’s been asked why he “threw away his career in neurology” by almost all of his peers. “Everybody knows you just give them steroids and you can’t fix it.”)
A couple hundred thousand people a year worldwide ain’t gonna pay enough to the pharma investors or make even one quarterly Wall Street nut. That’s just the reality of it.
So... we just take the drugs the cancer patients need to chill their immune systems out during certain types of chemotherapy — without the chemotherapy — and nearly all of them prescribed off-label.
The oncologists and rheumatologists get our drugs first. Big money there. Then they try them on us if older drugs aren’t working well or individuals have untenable side effects.
But we’re all pretty happy about the real-world numbers seen compared to our supposedly initial “high-risk”. Didn’t happen because those of us who don’t naturally stop having the reactions, are continually on the immune modifiers.
I suspect various other disorders and “co-morbidities” are experiencing similar helpful drug side effects, depending on the malady and the drugs used.
chemgeek
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The mRNA vaccines (Pfizer, Moderna) do indeed contain mRNA, although it includes some chemically modified RNA nucleotides to enhance stability. mRNA is "shovel-ready" instructions for manufacturing proteins in cells. The vaccine mRNA is encapsulated in a mixture of natural and artificial phospholipids for stability and to enable cellular entry. The inherent chemical instability of mRNA is why these vaccines must be stored at low or ultra-low temperatures. RNA has a pretty short half-life in cells, so once it does its thing (instructing the cell to make antigen spike proteins) it is rapidly degraded. The protein product initiates the immune response.
It is true that from an immune response viewpoint, it doesn't matter how the antigen gets presented. mRNA, plasmid DNA, viral vector RNA or DNA, pre-made protein or protein fragment, whole virus. The end result is neutralizing antibodies against antigenic proteins in the target virus.
GaryM
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Gary M
Thanks for the clarification.
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Llewtrah
I’ve shared this video in another thread. It’s an excellent description of how the Pfizer vaccine is made and in layman’s terms. I’ve found all of the stuff by medcram to be very good, including the ones on other vaccines.
N1120A
Pattern Altitude
Canada, which is starting to require tests for entry on 1/7, is stating they won't currently accept vaccination in lieu, but they have also been pretty aggressive on border policy during the pandemic. My guess is "traditional" tourist destinations will start accepting vaccination proof in time for summer season.
As for the test, most countries are accepting any NAAT test now, including rapid tests like IDNOW. Double check if that counts.
Eventually, we'll probably all get some sort of digital yellow card for COVID. In Africa, they usually will just give you the yellow fever shot if you show up without a yellow card.
As for the question whether the vaccine reduces the ability of the vaccinee to transmit the virus, BioNTech hopes to have the answer to that question 'by the end of Q1'. They also have testing going to see whether they can relax the storage requirements .
All the sites that have the IDNOW test are usually booked pretty full. We’ll see. I’m not going until the end of May so it can all change.
I would sure love to be able to visit Canada again.
I’d like to visit anywhere outside the USA again
.For now, I’ll stick to places in the USA
Cheers
Matthew Rogers
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PCR test in NY through Project Baseline came back in less than 48 hours for my brother a few days ago. Totally free and easy drive through at a pharmacy. Google it.
chemgeek
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Good news for Pfizer Phase 3 trial participants today. They have initiated steps to unblind the trial for all participants, and have reserved doses to get all participants who received the placebo their first dose of vaccine before March 1, 2021. Participants should know their status within about a week or so, depending on volume of requests. I think this action was ethically inevitable. With the deployment of vaccines being so slow nationwide, it is good to know there is a target time at which participants will receive vaccine and be able to gain a little additional personal freedom and assurance. Personally, I won't be anxious about traveling or shopping knowing I have whatever protection is technically achievable. It's annoying to be in a vulnerable age group, even if without co-morbidities. I have several friends and colleagues of similar age and health status who have had moderate to severe bouts with COVID, some with permanently disabling sequelae.
Glad the Pfizer Trial is treating the volunteers the same as the Moderna Trial. For some reason, it has taken longer to start the unblinding and offering the Vaccine to Pfizer participants but still, it’s going to get done. My Moderna Site started Monday, I was called in on Tuesday.
Cheers
Timbeck2
Final Approach
I got the Moderna vaccine yesterday. The literature is pretty funny in that it states: This vaccine is not FDA approved. This vaccine has not proven to prevent anything, etc, etc.
I just know that my arm is sore today. Other than that, nothing.
I just know that my arm is sore today. Other than that, nothing.
Zeldman
Touchdown! Greaser!
So...something like the placard on an EAB airplane?
Chemical and Engineering News just published an interesting infographic about what's in RNA vaccines. The Pfizer and Moderna ones are the most famous, they have been under study for some time for Ebola and other diseases. C&ENews is published by the American Chemical Society.
Link:
https://cen.acs.org/pharmaceuticals/vaccines/Periodic-Graphics-RNA-vaccines-made/99/i1
Link:
https://cen.acs.org/pharmaceuticals/vaccines/Periodic-Graphics-RNA-vaccines-made/99/i1
GaryM
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And a link at the bottom of that page takes you to the ACS graphic on Covid testing (nucleic acid vs. antigen testing). It also does a nice job of explaining how they work.
Ed Haywood
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I just had COVID. Should I still get a vaccine at some point?
chemgeek
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chemgeek
Yes, but not necessary for at least 90 days. The vaccine provides for more reliable and more robust immune response than natural infection. A recent study shows that those with mild disease lose antibody titers faster. Basically you got an immune bridge to our very slow vaccine deployment.