One-jab efficacy questions

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Useful info on whether the vaccine lower infection spread:

Preliminary analyses suggest that at least some vaccines are likely to have a transmission-blocking effect. But confirming that effect — and how strong it will be — is tricky because a drop in infections in a given region might be explained by other factors, such as lockdowns and behaviour changes. Not only that, the virus can spread from asymptomatic carriers, which makes it hard to detect those infections.

“These are among the hardest types of studies to do,” says Marc Lipsitch, an infectious-disease epidemiologist at the Harvard T. H. Chan School of Public Health in Boston, Massachusetts. “All of us are out there, hungrily trying to see what we can get out of little bits of data that do come out,” he says. Results from some studies are expected in the next few weeks.

https://www.nature.com/articles/d41586-021-00450-z
 
Luckily for us, the side effects of vaccines are manifested very early on ie in weeks. In 200 years of vaccination, contra indications have shown up quickly.

You are absolutely right that extreme caution is required with vaccines as they are given to otherwise healthy people, especially for the very young. That is why it usually take 5 to 10 years to develop a completely new vaccine (flue variants excepted). A vaccine is not a drug as such, so does not interfere with the body's metabolism or with DNA as a small molecule drug could, as Thalidomide did. A vaccine produces piece of virus protein, our bodies receive these all the time from natural infections. The side effects of vaccines are seen very quickly.

If there was a high incidence ie 1 in 10,000 of a side effect, it would show up in the early clinical trials, the ones granted a licence passed all these tests very well. The Covid vaccine is being rolled out globally to billions of people, we should start to see rare side effects (blood clots could be one such side effect) that affect say 1 in 250,000 or 1 in a million emerging. This data would help when rolling the vaccine out to the young, but so far trial are showing very little effect.
I agree with what your saying, I am not anti vaccine, I was just putting my tuppence worth in. I've had my letter a few week back, I just ain't been to get it, I've never heard off anyone in my area who has died with covid, and if any have, then it must be few in number, and my area has had an R rate below 1 for nearly 6 months. Still locked down though. Anyway the planet could do with loosing 2 or 3 billion people and if covid can do that, then it's not such a bad thing really.
 
Not really. They are the ones who find it hardest to get here and are least likely to be visited by freewheeling travellers.
It's the well off world travellers, whether for business or pleasure, who will spread it fastest.
There are over 1 billion slum dwellers. If we look at influenza it is rife in slums due to the high numbers and density of people, insanitary conditions, lack of health care, lack of vaccine, poor nutrition etc. I imagine that coronavirus is similarly rife. Slum dwellers do not stay in the slums, many go outside and work in the local communities. The very high number of Infections mean it is more likely for mutations to occur, then in to the wider community through possibly the slum dwellers who work outside the slum. From there to international travellers.

This is a worldwide problem
 
The planet doesn't give a dung. What nonsense!
The planet will survive pandemics, nuclear wars...
The human race may suffer, but that's hardly the same thing.
Do you consider yourself to be one of those the planet could do with "loosing"?
 
You seemed to be contradicting yourself. OK so you don't know but it's reasonable to assume that reducing infection will reduce transmission - unless/until it is shown to be otherwise.
If you accuse someone of contradicting themselves then you have to be very precise yourself. Vaccines do not reduce infection they produce antibodies which reduce the effect of the infection. That is what they are designed to do, protect the individual from the disease. They may also reduce the onward transmission of the disease but that is not measured in the approval process.

There is lots of talk about vaccine passports or negative Covid test to do certain things like go on an Aeroplane or the pub or football matches. To assume that the vaccinated group will not pass on coronavirus to the unvaccinated group seems a bit iffy to me. Surely we need to have some scientific basis that the vaccines we are using substantially reduce onward transmission before we go down this route.
 
On 18th March, Johnson said that 'a single dose of either Pfizer or AstraZeneca vaccine provides a 60 percent prevention from Covid-19 [he didn't specify which variant, not sure if that makes a difference] and that it reduces hospitalisation by 80 percent, as well as death by 85 percent'.
What did the PM say in his speech tonight, Thursday, March 18?
Two questions:
2. If we're 60% protected against contracting the virus, but the virus is now 50-70% more contagious than this time last year, aren't we back where we were last April in terms of likely spread? R seems to have risen to around 1 in England at the top end of the estimate, now.
Thanks if you can clarify any of this. Oh, and I don't want to know it's unimportant etc, just clarification on the stats.
Confused of Cardiff.
Your 2nd question
Although the Kent variant is more contagious and has a higher mortality rate especially for the young. Most data indicates that the current vaccines are equally effective at preventing serious infection from it as they did for the early variants.

So simple answer is , we are in a much better position than a year ago. A US study indicates that the AZ vaccine, after 3 weeks is close to 100% effective at preventing death and serous illness - that is way higher than the PMs March claim. Also UK data indicates that where there have been deaths and serous cases post vaccine, all the cases were from people with symptoms in the first week of taking the vaccine. They were either pre-infected, infected at the centre or shortly afterwards. Both AZ and Pfizer seem to be about as effective against the Kent variant as the previous strains of COVID.
A recent study in South Africa indicates the Pfizer vaccine is 80% effective against the SA strain, its probably safe to assume the AZ one will be as it produced anti-bodies against the spike protein as does Pfizer. Lab work had shown Pfizer to produce about 1/8th the antibodies to the SA variant compared to the normal variants, however the vaccines are so effective at producing antibodies that this lower number seems to be sufficient. The AZ vaccine tends to bost the T cells response which should help with immune memory - we will have to wait to see if this is borne out.

I have some experience of the vaccine programme, my company is working on the new variant vaccines. There seem to be several reasons to be optimistic going forward despite the appearance of more infectious variants and the expectation of still more variants.
- The virus mutates relatively slowly, much slower than flu, but faster than measles, so chances are the vaccines will hold up for a few more months by which time cases will be lower and the WHO etc will be able to focus on countries like Brazil where there are serous outbreaks
- Secondly new variant vaccines would be rolled out quite quickly. The mRNA technology is relatively quick to modify.
- We now know that vaccines are effective, 12 months ago its was an educated gamble - UK government put £13bn into the vaccine programme not knowing what would work, now the whole world industry is expanding rapidly. Within the next 12 months we will have global capacity to rapidly vaccinate the world population, which means we will get on top of the virus. At present there is not enough supply, that will change in a few months, the US and EU will have surplus supply and be exporting to the developing world. Once that happens new variants wont be produced so quickly and in such numbers.
- This was a new decease to mankind 12 months ago, so we had low natural immunity and it could produce bad symptoms, we know how to teat is better, we will carry residual immunity from vaccines which should reduce the seriousness of infection (CF Spanish flue) and we have medical treatments that are effective in reducing complications. We have better isolation practices and more available PPE
- we have effective assays to do test and trace at scale so can more effectively quarantine those with new variants and hence not to need the sledgehammer of a national lockdown so often if at all - we may see more draconian approaches to quarantine in the UK if other European countries find it effective as time goes on.
- even after lockdown has ended, we can still practice social distancing and continue to take sensible precautions until the disease is under control

So for all these reason we are in a much better place than 12 months ago, let the vaccine programme roll out and we should start to get on top of the disease. It will remain for a few years, but it should be consolable. There is a small chance that a variant will totally escape the vaccines, especially as that will be the evolutionary driver for the virus, but that worry seems a low probability, does seem to be the medical establishments biggest worry.
 
The planet doesn't give a dung. What nonsense!
The planet will survive pandemics, nuclear wars...
The human race may suffer, but that's hardly the same thing.
Do you consider yourself to be one of those the planet could do with "loosing"?
I think you missed the point, or it just went right over the top of your head, humans have raped the plant and caused global warming. I believe we are already past the tipping point, though you or I wont see it, the planet is already over populated, but your alright jack. dying doesn't worry me one bit
 
Anyway the planet could do with loosing 2 or 3 billion people and if covid can do that, then it's not such a bad thing really.

I take it you're not thinking of yourself as one of these 2 or 3 billion ;)
the planet is already over populated
Is it ?.
Some cities are densely packed, but much of the planet is uninhabited. in fact great swathes of land have nobody living there.
Here is a link to the Wikipedia page for the Earth. Earth - Wikipedia
According to this source, land occupies just over 29% of the Earth’s surface, or 148,940,000 square kilometres. There are 1,000,000 square meters in a square kilometre, so there are 148,940,000,000,000 square meters of land on the surface of the Earth. That’s approximately 150,000 billion square meters of land.

According to this source, World Population Clock: 7.5 Billion People (2017)
there are approximately 7.5 billion people currently living on earth.

If you divide 150,000 billion square meters by 7.5 billion people, you get about 20,000 square meters per person. You can think of that as a square about 140 meters on a side. That’s enough for a very nice house and a big garden.
 
@TominDales my partner falls right into the affected category for blood clots, uses the contraceptive pill and has a family history of strokes, biggest killer in her family and several survived but long term disabled.
 
Thanks for your really helpful reply, TominDales.
Your 2nd question
[...]
So simple answer is , we are in a much better position than a year ago. A US study indicates that the AZ vaccine, after 3 weeks is close to 100% effective at preventing death and serous illness - that is way higher than the PMs March claim.
That US study was after two doses, right? Johnson was talking about the effect of the first dose, and it was his stats relating to that that got me wondering - most of us who are eligible are in the one-dose state at the moment and many will be for some time to come as we unlock, schools are already back, and it's looking pretty busy out there at the moment (Easter hols, good weather etc.), and the Kent variant's much more easily transmitted than the original form we had (which by all accounts spread easily itself). Certainly, the broader context looks much better in terms of vaccinations and treatments.
 
If you divide 150,000 billion square meters by 7.5 billion people, you get about 20,000 square meters per person. You can think of that as a square about 140 meters on a side. That’s enough for a very nice house and a big garden.
Brilliant!I'll have my share along the south-west coast of France, down toward Hossegor. Not sure where the rest of you will go but i'd like nice neighbours. :)
 
If you accuse someone of contradicting themselves
Not an "accusation" just a suggestion :rolleyes:
...... Vaccines do not reduce infection they produce antibodies which reduce the effect of the infection. That is what they are designed to do, protect the individual from the disease. They may also reduce the onward transmission of the disease but that is not measured in the approval process.
Well yes. Brakes do not slow down a bicycle they merely stop the wheels from turning.
..... Surely we need to have some scientific basis that the vaccines we are using substantially reduce onward transmission before we go down this route.
Yes, but in the absence of scientific proof it's reasonable to assume that if the vaccines halt the disease this will probably halt the transmission
 
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This is a worldwide problem
Exactly, so the problem isn't the slum dwellers themselves it's the failure if agencies worldwide to alleviate slum dwelling and all the associated ills.
 
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Surely we need to have some scientific basis that the vaccines we are using substantially reduce onward transmission before we go down this route
No, I don't think we do.

This is a novel virus, decision making has to be done concurrently with data collection.

The difficulty with highly transmissible viruses is infection rates soar exponentially....slow decision making will always be too late.
 
The other thing worth noting is that after a second ("booster") jab the figures improve further by a reasonably encouraging margin. As suggested upthread, the biggest risk is from a new variant - developing where the infection rate is highest, most likely - evolving to evade the current set of vaccines. We know that the vaccines can be 'tweaked' within months, now that their basic function has been proven. The human race is not out of the woods yet - probably.

This variant nonsense is the media's last gasp at getting a scare out of people. I say that because there is no evidence that a variant that actually evades vaccines will develop any time soon.

As soon as there is, we'll know by the data, but for so long, we relied on the data to know how we're doing, and now we're supposed to ignore it. Even fauci is on this nonsense here.

Everyone I know who hasn't had covid is getting vaccinated, but if you watch the news, you'll be convinced that 50% of the population won't get it by misusing surveys.
 
So here we go again, as we get the numbers down and begin to get life more normal here in the UK with a high percentage of vacinations what does the government decide to do, lower the drawbridge and allow international travel with some hair brain traffic light system even with the virus staring them in the face. It could work if there was 100% compliance and measures in place to prevent onward travel but there won't be. So nothing to stop people going to a green country and then having their holiday in a red country and returning via the green country or going to a green country and coming into contact with others who have come in from a neighbouring red country so why lower the drawbridge just when things within are settling down and we have a fair measure of control.
 
This variant nonsense is the media's last gasp at getting a scare out of people. I say that because there is no evidence that a variant that actually evades vaccines will develop any time soon.
There was no evidence that Covid 19 was about to cause a global pandemic either until it happened.
 
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