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Vaccinated US nurse contracts COVID-19, expert says Pfizer shot needed more time to work - ABC


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12 hours ago, Credo said:

It's also important to remember it is about 95% effective, not 100% effective.   A small % will get the virus no matter what.   

95% from trials. I think over millions of doses and in a year or so, they will need to reassess efficacy. I think it will be lower than this percentage. Normal flu vaccines are generally 50-60% effective. 

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7 minutes ago, DavisH said:

95% from trials. I think over millions of doses and in a year or so, they will need to reassess efficacy. I think it will be lower than this percentage. Normal flu vaccines are generally 50-60% effective. 

Maybe. Maybe not.

“SARS-CoV-2 is mutating at a much slower rate than influenza,” WHO chief scientist Soumya Swaminathan said at a press briefing. “And so far, even though we’ve seen a number of changes and a number of mutations, none has made a significant impact on either the susceptibility of the virus to any of the currently used therapeutics, drugs, or the vaccines under development, and one hopes that that will continue to be the case.”

WHO says new Covid strain in U.K. appears more contagious (cnbc.com)

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4 minutes ago, DavisH said:

95% from trials. I think over millions of doses and in a year or so, they will need to reassess efficacy. I think it will be lower than this percentage. Normal flu vaccines are generally 50-60% effective. 

You can't compare flu vaccines to the coronavirus vaccines currently being developed and/or approved.

 

There are many different strains of flu, each requiring a different vaccine. The flu vaccines given out each year are based on predictions of which strain(s) of flu are expected to be prevalent in the coming flu season. They are essentially a form of guesswork. Quite often, the vaccinologists miss their guess, which obviously greatly reduces the efficacy.

 

Also, flu viruses are highly mutagenic, so even if they guess the right strain, the form of that strain that actually ends up being in circulation may be different enough from the old strain that the vaccine was developed for, as to make it less effective.

 

With this novel coronavirus, the vaccines have been developed based on a known, relatively stable virus which does not mutate at anything like the rate that flu viruses do, making it a more or less static target.

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Amazing!  Despite it being announced on American news networks repeatedly that the vaccines will not provide immunity from COVID-19, many people seem to be assuming that they will.  The vaccines will probably prevent many people from developing severe symptoms, but not from catching and transmitting the virus.  

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40 minutes ago, DogNo1 said:

Amazing!  Despite it being announced on American news networks repeatedly that the vaccines will not provide immunity from COVID-19, many people seem to be assuming that they will.  The vaccines will probably prevent many people from developing severe symptoms, but not from catching and transmitting the virus.  

Not so. It's not known whether the vaccine eill prevent infection.

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True enough but the percentages of effectiveness refer to the number of people who were infected but did not develop severe symptoms.  The whole trial population who were vaccinated was not tested in the USA.  The whole population in the UK was tested, hence the percentage of effectiveness there (70%) refers to a different thing.  The American numbers describe the number of infected people who did not develop severe symptoms.   Somehow a myth has grown that the American percentages describe the number of people who bacame immune to the virus.  People will believe what they want to.  The notion that 90% or 95% of people who are vaccinated will become immune to the virus is a comforting idea.  It just happens not to be true.  Only when complete testing of the Pfizer and Moderna vaccine recipients is carried out will we be able to determine the number of people who are then protected from contracting the virus.

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On 12/30/2020 at 8:21 PM, rabas said:

Not in the US.  A lot is already set up. CVS and Walgreens pharmacies are distributing Pfizer's vaccine to 1000s of facilities in Texas. Walmarts started vaccinating HCWs in New Mexico last week.

 

CVS, Walgreens, independent pharmacies, Albertsons, Tom Thumb, Randalls, Kroger, H-E-B, Walmart, Sam’s Club and Costco have been preparing for COVID-19 vaccinations by hiring thousands of pharmacists and related staff, such as nurse practitioners and physician assistants.

 

CVS alone says it will have the capacity to administer 20 million to 25 million shots a month nationwide.  reference

 

Can you get fries with that?

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10 hours ago, GroveHillWanderer said:

You can't compare flu vaccines to the coronavirus vaccines currently being developed and/or approved.

 

There are many different strains of flu, each requiring a different vaccine. The flu vaccines given out each year are based on predictions of which strain(s) of flu are expected to be prevalent in the coming flu season. They are essentially a form of guesswork. Quite often, the vaccinologists miss their guess, which obviously greatly reduces the efficacy.

 

Also, flu viruses are highly mutagenic, so even if they guess the right strain, the form of that strain that actually ends up being in circulation may be different enough from the old strain that the vaccine was developed for, as to make it less effective.

 

With this novel coronavirus, the vaccines have been developed based on a known, relatively stable virus which does not mutate at anything like the rate that flu viruses do, making it a more or less static target.

That sounds like good news.

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3 hours ago, DogNo1 said:

True enough but the percentages of effectiveness refer to the number of people who were infected but did not develop severe symptoms.  The whole trial population who were vaccinated was not tested in the USA.  The whole population in the UK was tested, hence the percentage of effectiveness there (70%) refers to a different thing.  The American numbers describe the number of infected people who did not develop severe symptoms.   Somehow a myth has grown that the American percentages describe the number of people who bacame immune to the virus.  People will believe what they want to.  The notion that 90% or 95% of people who are vaccinated will become immune to the virus is a comforting idea.  It just happens not to be true.  Only when complete testing of the Pfizer and Moderna vaccine recipients is carried out will we be able to determine the number of people who are then protected from contracting the virus.

Wrong. All the people in both the placebo group and the vaccinated group in the Pfizer trial reported symptoms. Not just severe symptoms.

"In the case of Pfizer, for example, the company recruited 43,661 volunteers and waited for 170 people to come down with symptoms of Covid-19 and then get a positive test. Out of these 170, 162 had received a placebo shot, and just eight had received the real vaccine."

From these numbers, Pfizer’s researchers calculated the fraction of volunteers in each group who got sick. Both fractions were small, but the fraction of unvaccinated volunteers who got sick was much bigger than the fraction of vaccinated ones."

Are Covid-19 Vaccines Really 95% Effective? - The New York Times (nytimes.com)

 

And it's not just the virus recipients who would have to be tested for infection. But those who received the placebo as well.

 

Also, early research seems to indicate that the asymptomatic are far less likely to transmit covid than those with symptoms.

What the data say about asymptomatic COVID infections (nature.com)

 

 

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11 hours ago, placeholder said:

 

Also, early research seems to indicate that the asymptomatic are far less likely to transmit covid than those with symptoms.

This.

 

In addition, in the case of the Oxford-AstraZeneca vaccine specifically, the published clinical trial data indicates that vaccination may well be effective in reducing or even preventing transmission.

 

As mentioned in the report linked to below, the data showed an:

 

Quote

Early indication that [the] vaccine could reduce virus transmission from an observed reduction in asymptomatic infections.

 

Oxford University vaccine breakthrough

 

Another section of that same report says:

 

Quote

These data also suggest that [the vaccine] could help to prevent transmission of the virus, evidenced by lower rates of asymptomatic infection in the vaccinees, with further information to become available when trial data are next evaluated.

 

Edited by GroveHillWanderer
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Also, if I'm not mistaken (and I don't think I am) the other vaccine manufacturers like Pfizer-BioNTech and Moderna have said that they hope and expect that their vaccines will reduce transmission - it's just that that wasn't a primary endpoint in their clinical trials so sufficient data to prove or disprove this was not collected and/or analyzed as yet.

 

Again, as more people are vaccinated, ongoing and future data collection and analysis will eventually be able to tell us whether transmission is indeed being reduced or prevented.

Edited by GroveHillWanderer
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Than you for referring me to the NYT article.   I had read a different explanation of how the percentages of effectiveness were arrived at.  The NYT does not give the exact calculations through which the percentages were derived.  It seems to be assumed  that the members of the placebo group and the vaccine group were equally exposed to infection.  I hope that additional data and explanations of how the effectiveness of the vaccines will be forthcoming.

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5 hours ago, DogNo1 said:

Than you for referring me to the NYT article.   I had read a different explanation of how the percentages of effectiveness were arrived at.  The NYT does not give the exact calculations through which the percentages were derived.  It seems to be assumed  that the members of the placebo group and the vaccine group were equally exposed to infection.  I hope that additional data and explanations of how the effectiveness of the vaccines will be forthcoming.

 

5 hours ago, DogNo1 said:

Than you for referring me to the NYT article.   I had read a different explanation of how the percentages of effectiveness were arrived at.  The NYT does not give the exact calculations through which the percentages were derived.  It seems to be assumed  that the members of the placebo group and the vaccine group were equally exposed to infection.  I hope that additional data and explanations of how the effectiveness of the vaccines will be forthcoming.

Actually, the date in the excerpt I chose gives all the information needed about how the 95% figure was arrived at.  The 95% figure could only be arrived at if the 2 groups were more or less equal in size. As for exposure to the virus, it would have to be random. To deliberately expose humans to a possible risk of serious illness or death would be at least immoral, and possibly illegal. That's why  43,000 volunteers were recruited.

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Thanks again.  After reading the NYT article once again, I understand the calculation but would not be able to do it myself.  The percentages are really preliminary figures that estimate the vaccines’ efficacy.  Some people are inferring that they indicate the vaccines’ effectiveness which the NYT article takes great pains to point out is a different thing.  Since AstraZeneca tested all of the recipients of their vaccine they can truly predict the effectiveness of their vaccine while Pfizer and Moderna can not.  
 

The article pointed out that the speed of the vaccines” deployment is as important as their effectiveness.  America seems to fumbling deployment as badly as they have fumbled on testing.  There is still no quick test available for Americans to buy and Dr. Fauci has complained about that as Dr. Birx did repeatedly before she “retired.”

 

The virus has become more contagious and is affecting more young people.   Rapid deployment of the vaccines has become more urgent.  Why was deployment not planned in advance? It easily could have been.

 

Here in Bangkok, the rapid deployment of a vaccine is also urgently needed.  It apparently will take the AstraZeneca licensee three months to brew up a batch of the vaccine.  I hope that Thailand will take a more proactive approach to the deployment of the vaccine here.

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