[nudephil (OP)]

Here's a question from Russ:

The flu jab presumably gives you a small dose of the flu virus, and then your own system kicks in. Does this mean that when you have this small dose, you then have the flu and can pass it on, as you possibly become contagious?

[Bored chemist]

"The flu vaccine cannot give you flu
None of the flu vaccines contains live viruses so they cannot cause flu."
from
https://www.nhs.uk/conditions/vaccinations/flu-influenza-vaccine/

This presumption

The flu jab presumably gives you a small dose of the flu virus

is mistaken.

[evan_au]

There are vaccines which use a live virus (it's just that the flu virus is not one of them: it uses a killed virus)

Sometimes the vaccine uses a different virus; the original "vaccination" for smallpox was with vaccinia virus, or cowpox. Cowpox causes few symptoms in humans, but is related to smallpox, and prevents humans from catching smallpox (smallpox is often fatal in humans).
- Some of the candidate COVID-19 vaccines use a live virus - one uses a monkey virus (which does not grow well in humans) 

Sometimes a vaccine uses a weakened form of the virus:
- Some polio vaccines used a weakened form of the polio virus
- And it's true, you could catch that weakened form of polio from someone else
- Once polio infection rates got very low, they switched to a killed polio virus as a vaccine (but it doesn't give quite as good protection)
- Today, after getting frustratingly close to total eradication of polio, there are now more cases of vaccine-derived polio than of wild-strain polio
- See https://en.wikipedia.org/wiki/Polio

See https://en.wikipedia.org/wiki/Vaccine#Types

[nudephil (OP)]

Here's a question from listener Richard:

Is it possible for a live and weakened viral vaccine to cause the disease it's supposed to prevent? If this is the case, has there been any change in the technology to produce these vaccines to make them safer?

[charles1948]

Here's a question from listener Richard:

Is it possible for a live and weakened viral vaccine to cause the disease it's supposed to prevent? If this is the case, has there been any change in the technology to produce these vaccines to make them safer?

We'll find out soon

[evan_au]

Astra Zeneca has used the monkey equivalent of "the common cold" to deliver their COVID-19 vaccine.

This original monkey virus doesn't grow well in humans - but if someone is immune compromised (eg after a kidney transplant), then perhaps the monkey virus could infect them. Note that it will give them a monkey cold, not COVID-19...

Astra Zeneca have modified the monkey virus to remove a critical gene that allows it to grow in living mammals (ie us), so it can't replicate in humans and cause disease.
- However, during vaccine production, they can externally provide the protein produced by the "missing" gene, allowing the virus to grow in the laboratory and factory.

That is one approach to make live-virus vaccines safer. 

Other vaccines don't use a live virus at all - that is another way to make vaccines safer.

[charles1948]

Astra Zeneca has used the monkey equivalent of "the common cold" to deliver their COVID-19 vaccine.

This original monkey virus doesn't grow well in humans - but if someone is immune compromised (eg after a kidney transplant), then perhaps the monkey virus could infect them. Note that it will give them a monkey cold, not COVID-19...

Astra Zeneca have modified the monkey virus to remove a critical gene that allows it to grow in living mammals (ie us), so it can't replicate in humans and cause disease.
- However, during vaccine production, they can externally provide the protein produced by the "missing" gene, allowing the virus to grow in the laboratory and factory.

That is one approach to make live-virus vaccines safer. 

Other vaccines don't use a live virus at all - that is another way to make vaccines safer.

Perhaps we should wait to see what happens to the early recipients of this new-tech "rushed into action" vaccine.

If they don't all start keeling over from heart-attacks, or developing brain-aneurisms, by say next December, that will
be a reassuring signal that it's safe to accept the jab in the arm.

Until then, I will avoid the jab.  Better safe than sorry, don't you think?

[alancalverd]

All vaccines have been tested for safety before being released even for their effectiveness trials. If you wait long enough, somebody somewhere will express a novel side-effect or allergic reaction, but you are more likely to suffer from COVID before that happens.

That's not scaremongering but statistics.Same as buying a single national lottery ticket in the hope of winning first prize next week - you are more likely to die than win.

[syhprum]

I will avoid the Oxford vaccine, chimpanzees by the brutal evolutionary process that creates herd immunity they have learned to live with AIDS type viruses that are lethal to humans.
As in fertilizes that are produced by the Haber process I would like my Vaccine produced by a completely synthetic process

[alancalverd]

Sadly, that will take you into the realm of homeopathy, which, although interesting, hasn't yet produced an inorganic vaccine. AFAIK all vaccines have a biological feedstock.

[charles1948]

Sadly, that will take you into the realm of homeopathy, which, although interesting, hasn't yet produced an inorganic vaccine. AFAIK all vaccines have a biological feedstock.

When you mention "homeopathy", aren't vaccines a practical demonstration of it

Isn't the basic doctrine of homeopathy this: "Like is cured by Like".

So, if you want to cure people from  Covid-19 virus, you inject them with the same virus, in a weak form.

The result is a cure.

Can anyone fault this homeopathic logic?

[evan_au]

start keeling over from heart-attacks, or developing brain-aneurisms, by say next December

By March/April 2020, people were keeling over from lack of oxygen and over-full hospitals. And some of them did have long-term heart and brain problems from COVID-19
- According to the news, it's starting to happen again.

So it's a cost/benefit analysis:
- If you don't have the vaccine, you have an average 1-5% chance of death when you eventually catch COVID-19, plus another 5% chance of long-term health problems.
- If you do have the vaccine, you reduce the chance of catching the disease by perhaps a factor of 10, and reduce the chance of severe disease by perhaps more than that (but the full details are not yet published in a peer-reviewed journal). Compared to that, there is a low chance of adverse reactions (but again, the full details are not yet published).

I expect that the results of the first clinical trials will be published before Christmas 2020, and then you then can make a decision based on evidence, rather than driven by fear-mongering and/or ignorance.
- In practice, when a vaccine is available to you will depend on government priorities and factory supply. So even when the evidence is available, you probably don't get a choice for a couple of months - you probably won't get vaccinated, even if all the evidence says you should have it.

[Bored chemist]

Can anyone fault this homeopathic logic?

Yes.
Anyone can refute it.
There's a question about calling it "logic".

The obvious point of difference is that homoeopathy thinks that you get an effect by diluting stuff down TO A POINT WHERE THERE IS NOT EVEN A SINGLE MOLECULE LEFT. That's magical thinking.
On the other hand, the current vaccine works by using the body's own protein synthesis  system to ensure that the number of immunogenic protein molecules  which produce the response is far bigger than the number of RNA molecules injected.

That's pretty cool.