Why does a vaccine have to be injected through a needle?

Why does a vaccine have to be injected through a needle?
Which cells do the protein synthesis from the mRNA of vaccines?
What doesn't light pass through opaque medium but from Transparent medium? What makes Opaque material "Opaque"?
What does "catching a cold" mean biologically?
What is the math behind the numbers of cases needed to declare efficacy of the recent vaccines?
Question about mRNA vaccines: what stops production of the new proteins?
Do we know how much energy exists as fossil fuels on Earth?
Are the Himalayas getting higher or shorter?
Do waves of virus infections depend on their contagious strains or are they influenced by human behaviour?
Is COVID-19 contagious for less than 10 days but the CDC is telling us 10 days just to be safe?
How are CPU clock speeds determined?
Does anyone know if there is a correlation between alcohol consumption and Covid-19 cases?

Posted: 24 Nov 2020 05:16 AM PST

If a virus, like Sars-Cov-2 can enter the body through orifices, why can't preventive medicine like vaccine? Wouldn't it be a whole lot nicer and easier to orchestrate if everyone could just get a nose spray "vaccine"? I'm sure if it were possible the brilliant minds of several scientists would've thought of it, so I know I'm not proposing something groundbreaking here, but I'm wondering why it is not possible.

submitted by /u/DePedro49
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Which cells do the protein synthesis from the mRNA of vaccines?

Posted: 23 Nov 2020 06:16 PM PST

One thing that I'm a bit fuzzy on are the specifics of mRNA vaccine protein synthesis because all explanations I've read of the process simply refer to a really generic ambiguous "host cell" that does the protein synthesis after it absorbes the mRNA from the vaccine.

mRNA (packaged in things like liposomes) is injected into the host.
These liposomes bind with host cells, the mRNA enters, and the host cell ribosomes synthesize proteins based off of the vaccine mRNA and presents these proteins on the outside of their walls. Do all kinds of cells uptake the vaccine mRNA and synthesize this protein? ie. the vaccine mRNA will be taken up by an assortment of epithelial cells, lymphocytes, myocytes, etc. and each of these will synthesize proteins based on the mRNA.
The body's immune system then identifies these surface proteins as foreign and proceeds to build up a memory of the antigen but also kills the otherwise various healthy (but antigen-presenting) cells in the process?

submitted by /u/rabidsoggymoose
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What doesn't light pass through opaque medium but from Transparent medium? What makes Opaque material "Opaque"?

Posted: 23 Nov 2020 07:11 PM PST

submitted by /u/Harshgamer3113
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What does "catching a cold" mean biologically?

Posted: 24 Nov 2020 02:49 AM PST

Is it only due to temperature difference? What are the physiological reactions taking place?

Is it due to an infection? If yes, which organisms and what the temperature has to do with it?

submitted by /u/Gabiboulga
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What is the math behind the numbers of cases needed to declare efficacy of the recent vaccines?

Posted: 24 Nov 2020 08:13 AM PST

Pfizer and BioNTech had 43,500 people in their test. They were able to release preliminary results once 94 of them had contracted COVID-19. They reached their final approval stage once 164 people had contracted the disease.

Similarly, Moderna had 30,000+ people, and released a preliminary report once 95 of them had contracted the disease. ~~I haven't been able to confirm the number of cases needed before final approval, but I assume it is about 180.~~ (EDIT: it's 151.)

Using the Pfizer-BioNTech example:

why were 94 cases the minimum number needed before any conclusions could be made about efficacy?
if 94 were enough for preliminary conclusions, what extra confidence does 164 cases give us, and why?
qualitatively, how is such a small number of cases (only 164) enough to make larger conclusions?

submitted by /u/REEEESES2
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Question about mRNA vaccines: what stops production of the new proteins?

Posted: 23 Nov 2020 11:59 PM PST

So I get that the mRNA bonds with host cells, the host cells then begin producing the protein encoded by the mRNA, and the immune system learns to fight that protein.

What stops the process? Will the host cells make the new protein forever?

Can the mRNA replicate inside a host cell?

submitted by /u/djc1000
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Do we know how much energy exists as fossil fuels on Earth?

Posted: 23 Nov 2020 07:10 PM PST

I realize that knowing where the energy exists is a problem, but do we know how much is actually left irrespective of location? Do we have a floor or a ceiling for the amount that could be left? Or is this an unanswerable question?

submitted by /u/_meshy
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Are the Himalayas getting higher or shorter?

Posted: 23 Nov 2020 12:49 PM PST

Which one is dominant - the erosion or elevation due to plate convergence? What about other mountain ranges? If any have a stronger effect, how long does it take for the need to overwrite the current records to arise?

submitted by /u/El_Basho
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Do waves of virus infections depend on their contagious strains or are they influenced by human behaviour?

Posted: 23 Nov 2020 05:26 PM PST

Cases rise, people become afraid, maintain precautions thereby cases drop. Cases reduce, people become careless and drop precautions thereby leading to a spike.

submitted by /u/abhictc
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Is COVID-19 contagious for less than 10 days but the CDC is telling us 10 days just to be safe?

Posted: 23 Nov 2020 04:30 PM PST

There's no way it's just instantly not contagious after the 10 day period. I've been thinking about it for the past few days.

submitted by /u/Alex_Yogi
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How are CPU clock speeds determined?

Posted: 23 Nov 2020 07:50 AM PST

Of the hundreds of instructions a CPU can perform, I assume they all don't take exactly the same amount of time to execute. Is the CPU clock calibrated to some "slowest" instruction?

submitted by /u/arizona_greentea
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Does anyone know if there is a correlation between alcohol consumption and Covid-19 cases?

Posted: 23 Nov 2020 08:49 AM PST

I've seen a blog stating 93% of all cases are non-drinkers. I don't believe it is true but couldn't find a reliable source too.

submitted by /u/bhanimeli
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