Covid Delta variant

  • #126
PeroK
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The Delta variant appears to have taken off in Spain, Portugal and the Netherlands, as well as the UK. In any case, there are large numbers of new cases in those countries again.
 
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  • #127
Ygggdrasil
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Regarding lack of indications, found this, what is your interpretation of this?

A perspective on potential antibody-dependent enhancement of SARS-CoV-2​

"At present, there are no known clinical findings, immunological assays or biomarkers that can differentiate any severe viral infection from immune-enhanced disease, whether by measuring antibodies, T cells or intrinsic host responses. In vitro systems and animal models do not predict the risk of ADE of disease, in part because protective and potentially detrimental antibody-mediated mechanisms are the same and designing animal models depends on understanding how antiviral host responses may become harmful in humans. The implications of our lack of knowledge are twofold. First, comprehensive studies are urgently needed to define clinical correlates of protective immunity against SARS-CoV-2. Second, because ADE of disease cannot be reliably predicted after either vaccination or treatment with antibodies—regardless of what virus is the causative agent—it will be essential to depend on careful analysis of safety in humans as immune interventions for COVID-19 move forward."
-- https://www.nature.com/articles/s41586-020-2538-8

/Fredrik

At the end of the section assessing the risk of ADE of disease with SARS-CoV-2, the authors write "In summary, current clinical experience is insufficient to implicate a role for ADE of disease, or immune enhancement by any other mechanism, in the severity of COVID-19 (Table 1)," which is consistent with the information I posted previously.

The research community is certainly aware of the possibility of ADE, which is why there are so many studies ongoing to assess the efficacy of vaccines and antibody-based treatments against the variants (as discussed above throughout the thread). Not only will these studies show whether the viruses can evade protection from the vaccines or treatments, but they can also show whether the vaccines or treatments lead to ADE and give worse outcomes for people given the vaccines or antibodies.
 
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  • #128
atyy
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Here's data with divided by age (Table 5, p16-17)
https://assets.publishing.service.g...ants_of_Concern_VOC_Technical_Briefing_18.pdf

50+
Unvaccinated: 71 deaths / 1267 Delta cases = 5.6%
2 doses: 116 deaths / 5234 Delta cases = 2.2%
Vaccine effectivess for preventing deaths ~ 60% (Oh, so low? But doesn't say how many days after 2 doses)

50-
Unvaccinated: 21 deaths / 70664 Delta cases = 0.03%
2 doses: 2 deaths / 5600 Delta cases = 0.036% (OMG :eek: I hope I've made absolutely silly mistakes in calculating)
Tweet by David Speigelhalter: "Latest PHE data: https://gov.uk/government/publications/investigation-of-novel-sars-cov-2-variant-variant-of-concern-20201201 Out of 257 Delta deaths, 118 (46%) fully vaxxed, 92 (36%) unvaxxed. What we would expect with high coverage by very effective – but not perfect – vaccine."

@PeroK and @pinball1970 made similar points earlier.

If the vaccine reduces deaths by (1-r). In an unvaccinated population x fraction die. In a vaccinated population (1-r)x fraction die. If v of the total population is vaccinated, then the fraction of deaths due to vaccinated people is z = [v(1-r)x]/[v(1-r)x + (1-v)x].

Solving gives r = [v - z]/[v(1-z)]. Using z = 0.46 from the data, and NHS data (page 4) that v = 0.9 or greater, we get r ~ 0.90. So the vaccine is ~90% effective in reducing Delta deaths. Much more reassuring, assuming again I haven't made errors.
 
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  • #129
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A woman in Belgium after simultaneously contracting two different Covid variants.

A 90-year-old Belgian woman who died from COVID-19 in March contracted both the UK and South African strain simultaneously, researchers said at a press conference on Sunday.

Her case, which was discussed at this year's European Congress on Clinical Microbiology & Infectious Diseases (ECCMID) as part of Belgian research, is believed to be the first of its kind.

The woman, who reportedly was not vaccinated, got sick in March and was treated at a hospital close to Brussels, according to Belgian broadcaster VRT.

https://www.yahoo.com/news/woman-died-covid-19-first-171023624.html

@Ygggdrasil or @atyy Are the variants so different that you can catch more than one at once, but the same vaccine works to prevent all? So, if you had the UK type, you could then apparently catch another variant because you would not have immunity, or is the difference that the woman caught both at the same time with no prior immunity to either?
 
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We must all get vaccinated. The Delta variant just makes it more urgent. But even before the variant really took off, at least in the UK (and because we use the same vaccines), likely Aus as well, achieving herd immunity was going to be difficult:
https://www.medrxiv.org/content/10.1101/2021.01.16.21249946v1

I think it may now be out of reach without second-generation vaccines targeting Delta and boosters:
https://www.news-medical.net/news/2...accine-based-on-SARS-CoV-2-Delta-variant.aspx

Thanks
Bill
 
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  • #131
atyy
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Are the variants so different that you can catch more than one at once, but the same vaccine works to prevent all? So, if you had the UK type, you could then apparently catch another variant because you would not have immunity, or is the difference that the woman caught both at the same time with no prior immunity to either?
I'm not sure about natural infection, but for the vaccines (say Pfizer) they reduce infection (asymptomatic and symptomatic) by about 85-95% for the alpha variant, and by about 60-80% for the Delta variant.

Alpha (or earlier variants):
https://www.cdc.gov/coronavirus/2019-ncov/science/science-briefs/fully-vaccinated-people.html

Delta:
https://www.thelancet.com/journals/lancet/article/PIIS0140-6736(21)01358-1/fulltext
https://www.reuters.com/world/middl...n-against-infections-still-strong-2021-07-05/
 
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  • #132
pinball1970
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We must all get vaccinated. The Delta variant just makes it more urgent. But even before the variant really took off, at least in the UK (and because we use the same vaccines), likely Aus as well. achieving herd immunity was going to be difficult:
https://www.medrxiv.org/content/10.1101/2021.01.16.21249946v1

I think it may now be out of reach without second-generation vaccines targeting Delta and boosters:
https://www.news-medical.net/news/2...accine-based-on-SARS-CoV-2-Delta-variant.aspx

Thanks
Bill

"Delta variant has been shown to be much more harmful than the Alpha variant, causing twice as many hospitalizations."

I thought DELTA was more transmissible but not necessarily associated with more severe disease?

A quick search suggests you are more likely to end up in hospital



https://www.bhf.org.uk/informations...virus-and-your-health/covid-variant#INDdeadly


Is the fact you are more likely to end up in hospital because the majority of cases are DELTA?

Also if DELTA is that more dangerous does that not mean that because deaths are still low the vaccine is doing an even better job that was expected?

Lots of questions!

Also on the paper was this link

https://www.news-medical.net/news/20210628/Study-suggests-vitamin-B12-as-a-SARS-CoV-2-antiviral.aspx

“The researchers employed a Quadratic Unbounded Binary Optimization (QUBO) model that runs on a quantum-inspired device to search for compounds similar to remdesivir.”
Probably better on another covid thread or may have been posted already but I thought that was interesting

Vit B less expensive and toxic that remdesivir.
 
  • #133
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Lets see if we see a first case of the UEFA-2020 mutation, resistant both to pfizer and alcohol.

/Fredrik
 
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  • #134
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Lots of questions!

Yes, there is. And researchers are working to answer them. But we must be careful in interpreting the data. I heard some commentators say Delta is less deadly because of data from the UK. A lot of people are vaccinated in the UK, so I am not sure that conclusion is warranted.

Time will be needed to sort it out.

Thanks
Bill
 
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  • #135
Ygggdrasil
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A woman in Belgium after simultaneously contracting two different Covid variants.

https://www.yahoo.com/news/woman-died-covid-19-first-171023624.html

@Ygggdrasil or @atyy Are the variants so different that you can catch more than one at once, but the same vaccine works to prevent all? So, if you had the UK type, you could then apparently catch another variant because you would not have immunity, or is the difference that the woman caught both at the same time with no prior immunity to either?

It is likely that the woman got infected with both variants at the same time with no prior immunity to either.

As @atyy state, the Pfizer vaccine seems effective against the newer variants. Studies have also shown that prior infection can also protect from re-infection, with efficacy similar to that of vaccination (example). While I have not seen studies on whether prior infection can protect against the newer variants, based on these data above (vaccines can protect against the newer variants and prior infection protects similarly as vaccines), I would expect that prior infection can protect, at least partially, from infection with the new variants and should likely give effective protection against severe disease, hospitalization and death. Consistent with this idea, studies looking at T-cells for both vaccinated individuals and indiviudials with prior infections suggest that the T-cells from these individuals can recognize the newer variant viruses (https://pubmed.ncbi.nlm.nih.gov/33594378/).

Regarding individuals, infected with multiple strains of the same virus, this is a rare event, but one that has been seen before both with influenza (https://www.sciencedirect.com/science/article/pii/S1386653215007404) and COVID-19 (https://www.sciencedirect.com/science/article/abs/pii/S0168170221000526?via=ihub).
 
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  • #136
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Isn't this rare case of getting infected with say two strains of the same virus just similar to having one strain but a higher viral load?
Because as far as I understand the main difference between the strains is the adaptation of the newer strains to better infect (attach) to the human cells in the respiratory system, so could I simply say that having two strains with one of the strains being the delta would be somewhat similar to like having the beta strain in higher viral load?

I guess there were some other mutations within delta that made it's disease form somewhat different although I don't know what causes the higher hospitalization and death rate from it whether it's the different form of the disease or simply the fact that it can enter more people and given that there is always a percentage of sick and weak people if a virus has higher transmission rate it can therefore affect more of the vulnerable etc. Somewhat like if we were able to give every single human on earth the regular flu we too would see large numbers of deaths in total. But don't take this as fact I am speculating here
 
  • #137
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The COVID Delta variant is a big change.
According to this Nature article (N=62+63):
Viral load is roughly 1,000 times higher in people infected with the Delta variant than those infected with the original coronavirus strain, according to a study in China.
It's accepted that this virus spreads through an aerosol - though the particle size is so small (smaller than tobacco smoke), I prefer to call it a "colloidal dispersion". There is every reason to expect that the density of that COVID "smoke" will track the viral load in the index patients respiratory track. And therefore, we should expect that the smoke is 1000 times the "viral load".
For the original COVID, virus trackers would look for an exposure time of about 15 minutes. If you divide that by 1000, you get an infection from a single breath!

There are some indications that it really is that potent.
From a recent MIT article:
During a June outbreak in Australia, where the virus had been previously well controlled despite an extremely low vaccination rate, New South Wales Health Minister Jeroen Weimar warned that transmission had occurred with only “fleeting contact” between individuals. For example, contact tracing and genomic sequencing showed that a woman in her 70s was infected while sitting outside a cafe visited by “Patient Zero,” an airport limo driver. In another instance, the virus seems to have been transmitted in the time it took for two unmasked strangers to pass each other in a shopping center, an encounter captured by mall security cameras.

But I don't think the claim that this virus spreads twice as fast (about R=4 vs. R=2), tells the whole story.

Here is a Boston News article reporting local Health Department statistics:
When analyzing the number of overall COVID-19 cases reported by the DPH between July 10 and July 16, the breakthrough cases account for 43.4 percent of all new COVID-19 cases.

Massachusetts doctors say the biggest cause is the arrival of the COVID-19 delta variant, which is twice as infectious than the original virus.

So we should also expect that this variant will be much hard to contain. If you know someone who is immune compromised, it could be very difficult to protect them from exposure.

It also means that anyone who was hoping to ride this out without getting either vaccinated or infected is likely playing a loosing game.
 
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  • #138
atyy
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It's accepted that this virus spreads through an aerosol - though the particle size is so small (smaller than tobacco smoke), I prefer to call it a "colloidal dispersion". There is every reason to expect that the density of that COVID "smoke" will track the viral load in the index patients respiratory track. And therefore, we should expect that the smoke is 1000 times the "viral load".
For the original COVID, virus trackers would look for an exposure time of about 15 minutes. If you divide that by 1000, you get an infection from a single breath!
Delta is more transmissible, but I'm skeptical of some of these specific ideas, especially the claims of transmission with fleeting contact. We have known since April 2020 that COVID-19 can be spread through aerosols in some circumstances, especially when ventilation is poor (https://www.medrxiv.org/content/10.1101/2020.04.16.20067728v1). There is not any good evidence that one has to worry about aerosols much more with Delta than with the original strain - ie. all non-pharmaceutical precautions for the original strain (safe distancing, mask wearing, ventilation, hand washing) should still work with Delta, and if you got infected with Delta, it doesn't mean that if you did the same thing, you would not have had a good chance of getting infected with the original strain - take a look at this report: https://pubmed.ncbi.nlm.nih.gov/33732749/. Before believing in the fleeting contact claim, I'd like to see something like sequencing data with good contact tracing.

And yes, vaccination is important, but one doesn't need Delta to know that. The breakthrough infections are not so much related to the increased transmissibility of Delta, as its ability to evade the immune response. So Delta's advanatge is partly due to a greater decrease of Alpha's fitness in the presence of previous infections or a vaccine. If one factors that in, the increase in transmissibility over Alpha is estimated to be between 1.1 to 1.4. https://www.researchsquare.com/article/rs-637724/v1
 
  • #139
atyy
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For the original COVID, virus trackers would look for an exposure time of about 15 minutes. If you divide that by 1000, you get an infection from a single breath!

There are some indications that it really is that potent.
From a recent MIT article:
Here is another reason I'm skeptical of the "fleeting contact" claim, which comes mainly from Australia. They made the same hypothesis with B.1.617.1 (Kappa). In fact the link given in the MIT article for the "fleeting contact" hypothesis refers to the Kappa variant, not the Delta variant. However, data suggests that the Kappa variant is not much more transmissible than Alpha (about which one would not take "fleeting contact" claims seriously).

https://www.theguardian.com/austral...more-infectious-than-previous-covid-outbreaks
Experts dispute Victoria claim that Kappa variant is more infectious than previous Covid outbreaks
 
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  • #140
PeroK
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Here is another reason I'm skeptical of the "fleeting contact" claim, which comes mainly from Australia.
Also, there's an estimate that currently 1% of the UK population has the Delta variant. If it could be passed on reliably with fleeting contact, then the numbers would be out of control. Whereas, the numbers appear to be settling down in the UK (to about 50,000 per day). In fact, if anything, the numbers are starting to fall.

We expect, however, that these numbers start going up again now that we have removed almost all the remaining restrictions.

PS only 40,000 new cases today, so definitely on the way down at the moment.
 
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  • #141
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A tipping point’: Kansas City hospitals are turning away patients due to COVID surge
https://news.yahoo.com/tipping-point-kansas-city-hospitals-193117650.html

KU has been turning down between one and six acute patients each day. If they had not been doing so, staff would be treating about 100 such patients, Stites said. Increasing COVID-19 infections could exacerbate the problem.

The Delta variant seems to be the predominant infectious agent in the US.

Missouri health officials on Wednesday reported the highest daily increase in infections since mid-January with 2,995 additional cases. The Missouri Independent, a news organization covering the state, reported that the seven-day average of cases rose to 2,144 per day, up “one-third in seven days and more than triple the average of June 21.”

In Alabama, a doctor has been telling her COVID-19 patients that it is too late to get the vaccine, and she tells some before they are intubated.

In Mississippi, seven children were in ICU for COVID-19, and two were on ventilators, as of July 14.
https://www.cnn.com/2021/07/14/us/mississippi-covid-children/index.html
 
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  • #142
atyy
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So we should also expect that this variant will be much hard to contain. If you know someone who is immune compromised, it could be very difficult to protect them from exposure.

It also means that anyone who was hoping to ride this out without getting either vaccinated or infected is likely playing a loosing game.
https://healthblog.uofmhealth.org/w...uld-i-keep-wearing-my-mask-once-im-vaccinated
If I’m Immunocompromised, Should I Keep Wearing My Mask Once I’m Vaccinated?

https://abcnews.go.com/Politics/cdc...compromised-people-boosters/story?id=79001113
CDC advisory committee voices support for immunocompromised people getting boosters
 
  • #144
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In Alabama, a doctor has been telling her COVID-19 patients that it is too late to get the vaccine, and she tells some before they are intubated.
WOW. I would have thought to get both doses and immunity to build will only take a few weeks (I think 5 weeks for Pfizer). You can strongly isolate during that time, so it may still be worth it. Here in Aus, it now is a race. NSW cant get Delta under control and are pushing vaccination hard. It is no surprise - its R0 is 5. So they think it is what should be done. We will need to wait and see.

Thanks
Bill
 
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  • #145
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New Zealand has paused quarantine-free travel between all of Australia from 11.59pm tonight:

As explained in the link, a national emergency has been declared here in Aus. We MUST vaccinate as quickly as we can. Preferably with Pfizer, but the AZ vaccine must be used as well. I have no issue with AZ because even getting out of bed has a 2.5 in a million risk of dying - greater than the now 1 in a million risk of dying from AZ. Rational commentators all agree it is plain silly to hold out for Pfizer. The issue is we are now doing over 1 million vaccinations a week, and increasing, so we can expect a death a week. We had 2 in the last week. They naturally get a lot of news coverage that scares the bejesus out of people, and out goes rationality. @StevieTNZ is a psychiatrist and may wish to comment on the psychiatric phenomena involved here.

Thanks
Bill
 
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  • #146
atyy
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In Alabama, a doctor has been telling her COVID-19 patients that it is too late to get the vaccine, and she tells some before they are intubated.
WOW. I would have thought to get both doses and immunity to build will only take a few weeks (I think 5 weeks for Pfizer). You can strongly isolate during that time, so it may still be worth it. Here in Aus, it now is a race. NSW cant get Delta under control and are pushing vaccination hard. It is no surprise - its R0 is 5. So they think it is what should be done. We will need to wait and see.
There's important context here. The comment by @Astronuc refers to a doctor addressing patients who are in a very serious condition with COVID-19.
https://www.al.com/news/2021/07/im-...eating-unvaccinated-dying-covid-patients.html

"... “A few days later when I call time of death,” continued Cobia on Facebook, “I hug their family members and I tell them the best way to honor their loved one is to go get vaccinated and encourage everyone they know to do the same.”

“They cry. And they tell me they didn’t know. They thought it was a hoax. They thought it was political. They thought because they had a certain blood type or a certain skin color they wouldn’t get as sick. They thought it was ‘just the flu’. But they were wrong. And they wish they could go back. But they can’t. So they thank me and they go get the vaccine. And I go back to my office, write their death note, and say a small prayer that this loss will save more lives.” ..." :cry:

Yes, obviously, if one is well and hasn't gotten the vaccine, one should get it as soon as it becomes available.
 
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  • #147
Astronuc
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I haven't seen the demographics on recent infections with SARS-Cov-2, but it appears younger people are being infected. Data are being studied, but anecdotally it seems the younger population are experiencing increased rates of mortality. Hospitalization rates of children with Covid-19 is about 1% compared to 15-20% of adult cases.

Although Delta appears to be more contagious than other variants, it does not appear to be more severe. One recent study from Scotland suggests the Delta variant is about twice as likely as Alpha to result in hospitalization in unvaccinated individuals, but other data has shown no significant difference.

Patel said research is ongoing to determine whether the strain leads to higher-than-expected deaths or hospitalizations.

https://news.yahoo.com/delta-varian...-contagious-coronavirus-strain-175513902.html

Edit/update:

Amanda Beinborn and her family had wanted to investigate vaccines further before deciding whether to get one. However, before she could find out more, the 20-year-old tested positive in June and her family members quickly followed suit.

Beinborn told News4Jax that said she was sick for four days before her parents and brother became ill too. She said her father, Dennis Beinborn, 55, was admitted to the ICU on July 3 and died on July 19 from the disease.
https://www.msn.com/en-us/news/us/w...tions-after-father-died/ar-AAMtMer?li=BBnb7Kz
In Arkansas, Angela Morris was left distraught when her 13-year-old daughter, Caia Morris Cooper, was put on a ventilator at Arkansas Children's Hospital in Little Rock, where she is fighting for her life.

She had resisted vaccinations for her and her daughter because she thought that masks and staying at home would suffice.
 
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  • #148
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I think the higher hospitalization rate for the Delta will turn out to be solely because it is more transmissible and therefore it sweeps a much larger part of the population and so many more of the elderly or sick or otherwise compromised folks get exposed.

If the regular flu had the opportunity to infect at the rate at which Covid does it too would be far lethal than currently.
Some years ago my grandpa died from kidney failure, they failed after he got a small cold which was most likely a virus since he lived only indoors and I probably brought the virus to him but i felt nothing and he suddenly developed a running nose and sore throat at first then it ended but as it ended he stopped urinating, I got him into the hospital and they swiftly took him to ICU where they performed dialysis because his kidneys had failed.
He was 90.
So technically if you are weak enough anything can take you down , probably even a sneeze.
 
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  • #149
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As explained in the link, a national emergency has been declared here in Aus. We MUST vaccinate as quickly as we can. Preferably with Pfizer, but the AZ vaccine must be used as well. I have no issue with AZ because even getting out of bed has a 2.5 in a million risk of dying - greater than the now 1 in a million risk of dying from AZ. Rational commentators all agree it is plain silly to hold out for Pfizer. The issue is we are now doing over 1 million vaccinations a week, and increasing, so we can expect a death a week. We had 2 in the last week. They naturally get a lot of news coverage that scares the bejesus out of people, and out goes rationality. @StevieTNZ is a psychiatrist and may wish to comment on the psychiatric phenomena involved here.

Thanks
Bill
since when was I a psychiatrist?
 
  • #150
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And then there are people like this guy, unbelievable.

A Louisiana man who contracted COVID-19 and wound up hospitalized said he would rather be ill than get vaccinated against the coronavirus.

The father and small-business owner recently caught COVID-19 and developed pneumonia, but he said he still would not have gotten vaccinated if that meant he could have prevented the infection.

"I would have gone through this, yes sir," Roe, , told CBS News' David Begnaud. "Don't shove it down my throat. That's what local, state, federal administration is trying to do - shove it down your throat."

When Begnaud asked what was being shoved, Roe said, "Their agenda is to get you vaccinated."
:bugeye:

https://www.yahoo.com/news/man-hospitalized-covid-19-told-160432588.html

Their agenda is to possibly save your life. HELL NO! Ain't NO ONE gonna save my LIFE!!! I'll save my OWN life or I'll die! o0)
 
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