Post by: Petrochemicals on 21/10/2021 01:13:29
Post by: evan_au on 21/10/2021 10:14:03
- But policies have not been uniform across Brazil - Rio de Janeiro had long periods of lockdown (only recently overtaken by Melbourne Australia as the city with the most lockdowns).
- So there are still likely to be pockets of susceptible people.
- I don't think anyone is carefully tracking infections in the jungle...
Apparently, in 2020, there was a town in Brazil where about 75% had been infected (showed COVID antibodies). But when Delta arrived, many became ill again. So a different variant can bypass immunity.
Brazil obtained supplies of the Chinese vaccine; efficacy was reportedly less than Astra-Zeneca, but even this would still help with immunity.. Presumably, the delta-specific antibody levels are even higher now, so they should be approaching herd immunity, and we should see a decline in Delta infections.
Post by: alancalverd on 21/10/2021 11:44:13
The good news is that the Brazilian Senate report makes a firm case for prosecuting the president, and hopefully sets a precedent for parliamentary and judicial action elsewhere.
Post by: Petrochemicals on 21/10/2021 15:23:18
I cannot see any evidence of a rise in infections, it may mean that they are not bothering to test and the vaccine is keeping the mortality numbers down.
600,000 is a mortality rate of about 0.3%, but this does not define how many are excess deaths over the normal. It may be possible to get a better picture of mortality rate from excess deaths.
Post by: Bored chemist on 21/10/2021 18:42:08
No.
Post by: alancalverd on 21/10/2021 19:08:41
600,000 is a mortality rate of about 0.3%,No, 3%. Same as pretty well everywhere else.
Post by: Petrochemicals on 21/10/2021 22:32:13
A 1% would be a population of 60 million, Britain is bigger than the uk.600,000 is a mortality rate of about 0.3%,No, 3%. Same as pretty well everywhere else.
Post by: set fair on 10/11/2021 17:41:29
If you make the optimistic guess that on average a person will be infeacted once every thousand days, then you can gei the average number of daily new infections by knocking three zeros off a country's population. In the UK that would be 68,000 new infections per day in the long term.
Post by: Petrochemicals on 11/11/2021 06:36:00
There are only two hopes that the virus has finished with Brazil - no hope and Bob Hope. Corona viruses like rhino viruses and flu have a life history which includes coming back to reinfect previously infected hosts.That is not what we have been told according to the herd immunity model, but then again the herd immunity does not seem to have come to fruition, it does not seem to work like the measles vaccine as the population of Britain has been largely vaccinated for over 6 months and still corona spreads, 99 percent of all people who are perishing with corona are not vaccinated so vaccination does not protect others.
If you make the optimistic guess that on average a person will be infeacted once every thousand days, then you can gei the average number of daily new infections by knocking three zeros off a country's population. In the UK that would be 68,000 new infections per day in the long term.
This Corona has only been around for 2 years so only 666 days so far, so no reemergence.
Post by: alancalverd on 11/11/2021 11:02:30
Britain is bigger than the uk.So The United Kingdom of Great Britain and Northern Ireland is smaller than Great Britain? Probably explains why every tax penny spent bribing Northern Ireland politicians disappears without trace.
Post by: Petrochemicals on 11/11/2021 12:14:01
Probably meant Brazil, that is where the 600,000 figure is from.Britain is bigger than the uk.So The United Kingdom of Great Britain and Northern Ireland is smaller than Great Britain? Probably explains why every tax penny spent bribing Northern Ireland politicians disappears without trace.
Post by: set fair on 18/11/2021 03:13:27
There are only two hopes that the virus has finished with Brazil - no hope and Bob Hope. Corona viruses like rhino viruses and flu have a life history which includes coming back to reinfect previously infected hosts.That is not what we have been told according to the herd immunity model, but then again the herd immunity does not seem to have come to fruition, it does not seem to work like the measles vaccine as the population of Britain has been largely vaccinated for over 6 months and still corona spreads, 99 percent of all people who are perishing with corona are not vaccinated so vaccination does not protect others.
If you make the optimistic guess that on average a person will be infeacted once every thousand days, then you can gei the average number of daily new infections by knocking three zeros off a country's population. In the UK that would be 68,000 new infections per day in the long term.
This Corona has only been around for 2 years so only 666 days so far, so no reemergence.
You're right herd immunity looks like a dead duck. I said back in december that with 70% vaccination, the virus would spread as readily in 2021 as it did in 2020. https://www.thenakedscientists.com/forum/index.php?topic=81316.msg623379#msg623379 We know that the other four human corona viruses aren't stopped by infection induced immunity so it was folly to think vacccination induced immunity would succed where "natural" immunity failed.
Post by: Bored chemist on 18/11/2021 08:46:49
it was folly to think vacccination induced immunity would succed where "natural" immunity failed.That depends on what you consider to be success.
A much lower death rate, slower spread and "flattening the curve" are real benefits.
The vaccine is already a succes.
Post by: set fair on 18/11/2021 10:50:48
it was folly to think vacccination induced immunity would succed where "natural" immunity failed.That depends on what you consider to be success.
A much lower death rate, slower spread and "flattening the curve" are real benefits.
The vaccine is already a succes.
Yes vaccines keep a lot of prople out of the morgue but in the post from which you quote I was addressing success in creating herd immunity.
Post by: Bored chemist on 18/11/2021 12:58:32
Post by: Petrochemicals on 18/11/2021 15:48:23
It does not look that way in Brazil for one country, it does look like herd immunity has been almost achieved.There are only two hopes that the virus has finished with Brazil - no hope and Bob Hope. Corona viruses like rhino viruses and flu have a life history which includes coming back to reinfect previously infected hosts.That is not what we have been told according to the herd immunity model, but then again the herd immunity does not seem to have come to fruition, it does not seem to work like the measles vaccine as the population of Britain has been largely vaccinated for over 6 months and still corona spreads, 99 percent of all people who are perishing with corona are not vaccinated so vaccination does not protect others.
If you make the optimistic guess that on average a person will be infeacted once every thousand days, then you can gei the average number of daily new infections by knocking three zeros off a country's population. In the UK that would be 68,000 new infections per day in the long term.
This Corona has only been around for 2 years so only 666 days so far, so no reemergence.
You're right herd immunity looks like a dead duck. I said back in december that with 70% vaccination, the virus would spread as readily in 2021 as it did in 2020. https://www.thenakedscientists.com/forum/index.php?topic=81316.msg623379#msg623379 We know that the other four human corona viruses aren't stopped by infection induced immunity so it was folly to think vacccination induced immunity would succed where "natural" immunity failed.
Post by: alancalverd on 18/11/2021 16:03:08
If you look at the cases reported per day in Brazil you can see a few enormous peaks of up to 150,000 on a single day, standing out from an average of 35,000. This suggests something very sporadic and therefore unreliable in the reporting system.
Worth comparing the largely unknown quantity of Brazil, with about 3.5% of the population reported as infected to date, with the well-characterised statistics of the UK (easy communication, free health service, relatively little official corruption....) showing 17% infected to date. If the stats are credible and herd immunity is possible, the UK will obviously get there first.
Post by: Petrochemicals on 18/11/2021 16:38:07
Improbable. You need to distinguish between herd immunity, where the next generation does not express symptoms after infection, and saturation of the reporting system, which is apparent from the shape of the cumulative cases curve and tells you nothing about the immunity of the population if the sampling is inefficient.Politically Alan, the medics are ready to attribute anything negative to bolsonaro. All of these lockdowns could end up exasserbating the situation by prolonging the duration of the critical period and giving corona more time to infect the vulnerable.
If you look at the cases reported per day in Brazil you can see a few enormous peaks of up to 150,000 on a single day, standing out from an average of 35,000. This suggests something very sporadic and therefore unreliable in the reporting system.
Worth comparing the largely unknown quantity of Brazil, with about 3.5% of the population reported as infected to date, with the well-characterised statistics of the UK (easy communication, free health service, relatively little official corruption....) showing 17% infected to date. If the stats are credible and herd immunity is possible, the UK will obviously get there first.
Post by: alancalverd on 18/11/2021 16:56:45
Post by: Bored chemist on 18/11/2021 17:21:08
Politically Alan, the medics are ready to attribute anything negative to bolsonaro.They can do it scientifically too.
Post by: Bored chemist on 18/11/2021 17:21:58
it does look like herd immunity has been almost achieved.It is far too early to tell.
Come back in 3 years.
Post by: Petrochemicals on 19/11/2021 15:53:50
It will always infect the vulnerable. In fact it will infect anyone who isn't vaccinated (and a few who are), but only kills the most vulnerable. It just takes longer to infect a rural population.I would not call Austria rural, plus it seems to be spreading amongst the vaccinated.
I begin to wonder whether the astra zenica is better than the Pfizer in longevity of protection.
Post by: evan_au on 20/11/2021 06:44:48
Quote from:
herd immunity looks like a dead duckIf natural immunity is lifetime, there is a good chance that a vaccine will also give lifetime immunity, eg measles.
If natural immunity is almost non-existent, a vaccine will be a real struggle, eg HIV/AIDS.
One could conclude that if natural immunity lasts a only few years, the vaccine might only last a few years, too, eg influenza or coronaviruses (COVID is a member of this family).
In the shorter term, a form of herd immunity might be achievable with high vaccination rates. The following is a back-of-the-envelope calculation:
- Delta strain is thought to have an R0 around 6-8 (let's call it 7)
- That means, in the absence of other measures (like masks, or social distancing), one infected person will infect about 7 others, on average.
- The infection will die down if each infected person comes in contact with less than 1 susceptible person.
- If the vaccine were 100% effective, that means you would need a vaccination rate of > 6/7 or >86%
- We know that the current vaccines only give about 50% protection against Delta, after 6 months.
- That means you need a vaccination rate of >13/14, or >93%
- Some countries are approaching this level of vaccination, like parts of Australia
- Infection by the virus itself also provides immunity, so you need a (vaccination+infection) rate of >13/14, or >93%
- Wearing masks and social distancing also reduce transmission significantly
- So there are signs that Delta could be contained for now, in some countries
- Other variants are a lottery!
There are differences in the type of immunity produced by vaccination & natural infection:
- The vaccines just target part of the spike protein, while natural infection will generate antibodies to many parts of the virus
- The vaccine-induced antibodies tend to neutralize the virus so it can't infect cells; not all natural infections produce neutralizing antibodies
- If the spike protein mutates, the vaccines may lose much of their effectiveness, while natural infection will still have antibodies that recognize other, non-mutated parts of the virus, so it is a broader immunity.
Apparently, being vaccinated halves your chances of catching COVID (a breakthrough infection), and if you are infected, halves your chance of getting Long COVID. So that's a bonus for risk of disability!
See: https://theconversation.com/long-covid-double-vaccination-halves-risk-of-developing-long-lasting-symptoms-165270
Post by: Petrochemicals on 13/06/2023 10:19:26
Post by: alancalverd on 13/06/2023 13:44:50
Post by: Petrochemicals on 13/06/2023 16:41:07
Huge difference in the"population pyramid". Brazil has a bulge around age 30 - 50 compared with UK an Scandinavia which have a larger proportion of older folk. And we have no idea of the true figure for the rural population of Brazil.Of course, adjust the evidence to fit your opinion, it makes perfect sense! They many now be under reporting to buoy up De Silva, which would mean they over reported to sink Bolsonaro, but I think it's a bit much to call Brazil is a crap country compared to the UK or usa Alan. Brazil also has more native people who have proven to be more susceptible.
Fact is Brazil was ahead, is now behind, Norway not excelling, new Zealand half as bad as the UK.
Post by: Bored chemist on 13/06/2023 17:14:18
Of course, adjust the evidence to fit your opinionTell me, How did Alan adjust Brazil's demographics?
I think it's a bit much to call Brazil is a crap countryYou are the only one to have used that adjective...
Post by: Petrochemicals on 13/06/2023 19:36:29
I would think that it is more to do with virus mutation characteristics, influenza is known to mutate to evade the immune system. As we have been told the usual path is to mutate to less lethal forms. Natural immunity to small pox was low, so too tuberculosis, yet highly effective vaccines do imbue herd immunity.Quote from:herd immunity looks like a dead duckIf natural immunity is lifetime, there is a good chance that a vaccine will also give lifetime immunity, eg measles.
If natural immunity is almost non-existent, a vaccine will be a real struggle, eg HIV/AIDS.
In the shorter term, a form of herd immunity might be achievable with high vaccination rates.But it was not as the vaccines where no where near effective enough and also had many severe side effects, people ending up in hospital etc. The polio vaccine took decades to develop.
Post by: paul cotter on 13/06/2023 19:46:40
Post by: alancalverd on 13/06/2023 23:32:21
It's statistics, not genetics, which is why sensible folk worry when childhood immunisation rates decline before the critical point at which the virus loses the game.
Stalin said "one death is a tragedy; a million deaths is a statistic". This was never more true than in the antiscience of COVID reporting. There are indeed a few egregious sideffects leading to disability or death, but the problem with a mass vaccination program is that whilst every such case makes headlines, we never know how many lives have been saved. The only measure of success is a declining excess mortality after the introduction of the program, but if you start early and vaccinate everyone, which is the ethical thing to do, the initial excess mortality will be too low to measure the difference!
Chris Whitty said at the beginning of the UK vaccination and quarantine campaign "If, in a year's time, people ask what all the fuss was about, we will have got it right." Or maybe wasted millions of pounds - we'll never know!
Post by: Petrochemicals on 14/06/2023 01:12:59
Herd immunity doesn't imply a change in the genetics or physiology of members of the herd,
It would not be expected to alter the herds study of the physicality of biological entities, given it is an interlectual foray into an unknown realm. It does however alter the physiological make up of the herd due to it imbuing protection through creating an antibody reaction within the hosts to stop infectious existences, thusly stopping the microorganism infection permiating through the herd to the most vulnerable members who perhaps cannot be vaccinated against said virus.
The corona jabs did not do the above, they did not. They failed at herd immunity creation. It is questionable whether the children, who have only just started out in life, benifitted from the vaccination programme. It certainly didn't stop them catching corona and passing it on a la Measles.
https://dictionary.cambridge.org/dictionary/english/physiology
Herd immunity may be something created of the genetics of the future such as the AIDS, we could all be gene edited.
Physiological, phy-si-o-lo-gi-cal.
Post by: Petrochemicals on 14/06/2023 01:39:16
The vaccines have a low rate of side effects. Any medical intervention carries some risk. The covid vaccines were produced rapidly as technology had advanced since the time of the polio vaccine.Yes but the children still became infectious with corona and spread it, some died from the vaccine, arguably more than would have died without the vaccine. This did not stop the virus spreading.
https://fullfact.org/health/covid-vaccine-deaths-children/
The virus programme stinks to high heaven of hush ups, it was a failure in preventing the spread, it just has to be touted as a sucess to justify arresting the entire country for 2 years. There was an excellent way to bestow herd immunity on the super spreader community, that was called let them catch the virus.
As for vaccines, they have the effect of creating a weaker populace by ratio. The more you save the more vunerable your population becomes, the pandemic of corona situation will recurr more often as people gain ever more medical intervention.
Post by: Bored chemist on 14/06/2023 09:04:55
The corona jabs did not do the above, they did not.How do you know?
The thing about "herd immunity" is that there are two overlapping versions.
The old (medieval) one is where you ignore the virus and let it kill those who are susceptible.
After that, the herd of survivors are immune.
That's the version which, at least some, Tories wanted.
It results in essentially the highest possible death toll.
And it's what PC wanted.
There was an excellent way to bestow herd immunity on the super spreader community, that was called let them catch the virus.
The second version is where you somehow "make" the herd immune- typically by vaccination, though you could do it by dosing them with anti-infective drugs.
If it was bubonic plague, you could create herd immunity by giving everyone Streptomycin . (this is usually a very bad idea- but it's workable locally in some cases- dosing everyone who was present when someone opened an envelope full of anthrax spores or whatever).
The thing is that the two types of herd immunity will overlap unless you can get the vaccinations done before the disease arrives (we sort of seek to do this with flu every year).
If there's and outbreak, after a while, the herd will have a much lower susceptibility to infection.
Some of that will be due to vaccination and some to "natural" infection.
And with a virus like covid which can be asymptomatic, it's impossible to tell which contributed more.
So PC is making a claim that he can't possibly back up.
That's more or less the reason for the footnote about me in all his posts.
Post by: paul cotter on 14/06/2023 10:10:18
Post by: alancalverd on 14/06/2023 18:33:18
They failed at herd immunity creation.Simply because initially the virus spread (thanks to government action and inaction) faster than anyone could develop, test and manufacture a vaccine. Once the WHO had established it as a world target it took 70 years to eradicate smallpox with a well-characterised vaccine. And there were indeed side effects. Similarly polio, which had been around for centuries.
The only question worth asking is what would have happened without quarantine and vaccination? Fortunately we know the answer from Matt Hancock's unethical experiment.
Post by: Petrochemicals on 14/06/2023 19:20:44
Petro, I suspect you have become an anti-vax conspiracist. Do you suggest that we cease all medical interventions and hence improve our genetic standing? That's fine in theory until you are the patient requiring said intervention.There is nothing to suggest that in anything I have typed, it is rather defamatory. Do you suggest we should give up on being vigilant on polio vaccines or take up homeopathy?
Post by: Petrochemicals on 14/06/2023 19:32:02
Because the vaccination programme implementation imbued immunity? Or was it the virus continued to spread.They failed at herd immunity creation.Simply because initially the virus spread
To the untrained eye it could look like scientists and politicians tried to appear capable, came up with a vain plan, harped on about their glorious success and then swept any quantification of performance under the carpet, sodded it as a bad job, left everyone to cop it and moved on saying nothing of the performance.
Herd immunity. New Zealand, bastion of corona awareness, reliant on vaccine development is at about half the level of corona mortality than that of Sweden, vilified Scandinavian sluggards. Remember pre vaccine new Zealand had been successful at isolation and quarantine. It looks like NZ gave their corona policy up as a bad job too, a shame that their Ernstwhile ex Pm is not there to answer for it.
Brazil now better than the UK.
Post by: paul cotter on 14/06/2023 20:59:21
Post by: Bored chemist on 14/06/2023 21:20:33
There is nothing to suggest that in anything I have typed,Well...
99 percent of all people who are perishing with corona are not vaccinated so vaccination does not protect others.That's a non seq.
in Brazil for one country, it does look like herd immunity has been almost achieved.
the vaccines where no where near effective enough and also had many severe side effects, people ending up in hospital etc
And things like "
the medics are ready to attribute anything negative to bolsonaro
under reporting to buoy up De Silva, which would mean they over reported to sink Bolsonaro
Look like conspiracy stories to me.
So, yes, you did type stuff that makes you look like an antivax conspiracist.
Post by: Petrochemicals on 14/06/2023 21:52:19
Petro, if you feel my comment was defamatory, then I apologise, but I thought that was the direction you were headed in. All of this argument is after the event and no one knew at the time how bad the situation could get. Remember that there is only one exact science and that is hindsight.That is rather indistinct considering you where suggesting taking any vaccine at any time, I said nothing to suggest conspiracy, if government skimming over uncomfortable facts were conspiracies HS2 would be the arch villain. I did ask whether you would espouse homeopathy?
Post by: alancalverd on 14/06/2023 23:09:37
swept any quantification of performanceExcess death statistics have always been available, and are credible in those countries that have effective mandatory registration of deaths.
It looks like NZ gave their corona policy up as a bad jobThey had to resort to mass vaccination and crossed fingers after an airline crew broke quarantine and infected their first cohort. But as with any other vaccination program, it started too late for the first victims and thanks to antisocial media it's very difficult to establish herd immunity quickly. As with smallpox, we won't know if we have won for at least 20 years.
Post by: Petrochemicals on 14/06/2023 23:51:03
Nonsense. New Zealand completes vaccination before it opened borders, whatever immunity was garnered from the programme was already present. Vaccination imbued herd immunity did not occour! The government gave up! The vaccines to not give immunity from corona infection, herd or otherwise.swept any quantification of performanceExcess death statistics have always been available, and are credible in those countries that have effective mandatory registration of deaths.It looks like NZ gave their corona policy up as a bad jobThey had to resort to mass vaccination and crossed fingers after an airline crew broke quarantine and infected their first cohort. But as with any other vaccination program, it started too late for the first victims and thanks to antisocial media it's very difficult to establish herd immunity quickly. As with smallpox, we won't know if we have won for at least 20 years.
Post by: paul cotter on 15/06/2023 08:40:37
Post by: Petrochemicals on 15/06/2023 12:03:31
Petro, for the record ( a ) I would take any vaccine that the science at that time deemed necessary ( b ) I live in Ireland so talk of hs2 is immaterial to me ( c ) I do not espouse homeopathy, it is abject nonsense. I think i'll drop out of the discussion now, as it is going nowhere.Homeopathy is about as effective at creating herd immunity as the corona jab is the point? As for conspiracy
https://en.m.wikipedia.org/wiki/Irish_political_scandals
Post by: alancalverd on 15/06/2023 13:09:09
Even if you accept the precepts of homeopathy, it (in its classic form) depends on a very personalised diagnosis of existing disdease and is therefore as unsuitable for mass preventive care as knee surgery.
Herd immunity is a statistical result of immunising a closed group to the point that R << 1. That point has just about been reached in respect of poliomyelitis and definitely in the case of smallpox, but thanks to antisocial media, the growth of superstition, and the profitable baying of ignorant anti-humans we will probably never achieve it again.
Post by: Petrochemicals on 15/06/2023 14:16:38
herd immunity, and neither does vaccination by itself, as I explained earlier.Yes, yes it does. We where promised a vaccine that would give herd immunity if we waited in lock downs for years. It failed to materialise. If not what were children given corona vaccinations for? They seem to be more than capable of developing immunity the normal way.
Herd immunity is a statistical result of immunising a closed group to the point that R << 1Yes, which was promised but didn't happen.
Post by: alancalverd on 15/06/2023 14:50:05
The maths is pretty obvious, despite the variable quality of the data. Excess deaths and the rate of infection were high in states with dense urban populations and groups with low vaccination uptake.There is some more advanced mathematics concerned with delayed and amplified propagation, but it requires a receptive audience, not a prejudiced one. But a lesson worth learning is that you should never trust a politician, especially when he says "trust me".
Post by: Kryptid on 15/06/2023 17:21:02
There is nothing to suggest that in anything I have typed
Actually...
As for vaccines, they have the effect of creating a weaker populace by ratio. The more you save the more vunerable your population becomes, the pandemic of corona situation will recurr more often as people gain ever more medical intervention.
You imply here that using medicine to save the weak is bad, particularly in light of what you said just before that:
There was an excellent way to bestow herd immunity on the super spreader community, that was called let them catch the virus.
Post by: Bored chemist on 15/06/2023 23:09:38
Deliberately placing infective persons in contact with vulnerable others as was ordered by the UK Health Secretary, is prosecutable as a war crime.Only if there's a war.
Otherwise it's just simple multiple murder.
Post by: Petrochemicals on 15/06/2023 23:59:42
Nope, just your interpretation, but rather than thinking about the statement and what would happen to the populace without medical intervention, or even asking me, you have told me what I said, either in error or deceit.There is nothing to suggest that in anything I have typed
Actually...As for vaccines, they have the effect of creating a weaker populace by ratio. The more you save the more vunerable your population becomes, the pandemic of corona situation will recurr more often as people gain ever more medical intervention.
Post by: Petrochemicals on 16/06/2023 00:02:05
Note the word "if". Every outbreak is traceable (in principle) to an infective person making contact with others - COVID isn't magic, and neither is quarantine. Deliberately placing infective persons in contact with vulnerable others as was ordered by the UK Health Secretary, is prosecutable as a war crime.But the vaccines did not create herd immunity. See graphic illustration in earlier post about new Zealand.
The maths is pretty obvious, despite the variable quality of the data. Excess deaths and the rate of infection were high in states with dense urban populations and groups with low vaccination uptake.There is some more advanced mathematics concerned with delayed and amplified propagation, but it requires a receptive audience, not a prejudiced one. But a lesson worth learning is that you should never trust a politician, especially when he says "trust me".
Post by: Kryptid on 16/06/2023 00:27:40
Nope, just your interpretation, but rather than thinking about the statement and what would happen to the populace without medical intervention, or even asking me, you have told me what I said, either in error or deceit.
When the statement about vaccines and medical treatment immediately followed a statement calling letting people catch the virus an "excellent" way of reaching herd immunity, how are we supposed to interpret that?
Post by: Petrochemicals on 16/06/2023 08:51:19
Precisely the point.Nope, just your interpretation, but rather than thinking about the statement and what would happen to the populace without medical intervention, or even asking me, you have told me what I said, either in error or deceit.
When the statement about vaccines and medical treatment immediately followed a statement calling letting people catch the virus an "excellent" way of reaching herd immunity, how are we supposed to interpret that?
Post by: Bored chemist on 16/06/2023 14:16:32
But the vaccines did not create herd immunity.Nothing ever does.
It's a hypothetical ideal where absolutely everyone is totally immune.
And you can't do it- not least because the virus changes and people do too.
A vaccine can't do it (because you can't administer it to everyone- some will be allergic or whatever)
And you can't even do it by allowing the virus to run riot- because it will always miss some people- even if it's just newborn babies.
But what the vaccine did was save lives.
It did that two ways- firstly (and obviously) it reduced the harm in people who were exposed (They were less likely to get covid, less likely to have severe symptoms, less likely to get long covid and less likely to die.)
So the vaccine is an unequivocally good thing.
The second way the vaccine saved lives was to slow the transmission of the virus through the population, thereby making it easier for healthcare systems to deal with those severely affected.
The point is that, by reducing the spread of the virus, vaccination got us much closer to herd immunity than we would have got without it.
And it did so without mass human sacrifice which is what the traditional type of "herd immunity" means.
PC seems to favour the version with the bigger death toll.
He doesn't seem to want to say why.
Post by: alancalverd on 17/06/2023 00:25:22
Wikipedia puts it succinctly:
Quote
For simple models, the proportion of the population that needs to be effectively immunized (meaning not susceptible to infection) to prevent sustained spread of the infection has to be larger than 1 - 1/R This is the so-called Herd immunity threshold or herd immunity level. Here, herd immunity means that the disease cannot spread in the population because each infected person, on average, can only transmit the infection to less than one other contact.
But there is no "simple model" in practice because
(a) R is a function not only of the disease itself but also of the social habits of the population, which is why you need quarantine (theoretically 100% effective at eliminating transmissible disease) plus vaccination to account for the fact that 100% quarantine is not possible outside of a prison or specially-designed hospital and
(b) no vaccine is 100% effective against an evolving virus - we can only vaccinate for last week's most popular or most virulent version, and as COVID symptoms have several days' latency whilst the carrier is infectious, we don't really know which variant is the most virulent until it is too late.
Post by: set fair on 17/06/2023 14:53:16
... compared to the UK or usa Alan. Brazil also has
Didn't he play for Spurs?
Post by: set fair on 17/06/2023 17:03:02
Post by: Bored chemist on 17/06/2023 17:58:19
The expectation that we could achieve herd immunity through vaccination was collective madness.Worked for smallpox.
Again, you seem to think that herd immunity is some"perfect" state where everyone is completely immune.
In fact it only requires that any infection will die out (eventually).
Post by: alancalverd on 17/06/2023 18:11:51
The expectation that we could achieve herd immunity through vaccination was collective madness.Who expected it? Maybe the Trumpian herd (except they didn't believe in vaccines) or the Disciples of Boris, but nobody with an ounce of common sense would believe that herd immunity could be achieved in the face of gross public ignorance and the Human Rights brigade.
o achieve herd immunity there would have had to be a reason to believe that the vaccines could induce the immune system to do something that it can't do by infection induced immunity.Quite so. And that "something" is to generate effective antibodies before the target virus arrives.That's the historic difference between variolation (using a dilute sample of the infective agent variola) and vaccination (using cowpox agent vaccinia to protect against variola).
Post by: paul cotter on 17/06/2023 21:35:08
Post by: set fair on 17/06/2023 22:03:26
The expectation that we could achieve herd immunity through vaccination was collective madness.Who expected it? Maybe the Trumpian herd (except they didn't believe in vaccines) or the Disciples of Boris, but nobody with an ounce of common sense would believe that herd immunity could be achieved in the face of gross public ignorance and the Human Rights brigade.
Who expected it? You did
So can the vaccine give us herd immunity if enough of the population have it, or will the virus continue to circulate anyway until a vaccine-resistant mutant emerges?
Yes and yes, because herd immunity isn't the same as inherent tolerance or immunity. If 80% of the population is immune through vaccination or prior infection, the probability of anyone else being infected becomes very small (herd immunity) but those that are infected can indeed breed mutants.
Post by: evan_au on 17/06/2023 23:43:21
Quote from: Wikipedia, quoted by alan calverd
1 - 1/R...Herd immunity thresholdThe original strain of COVID had R around 2 or 3.
1-1/R=1-1/2.5=0.6, so the WHO's target of a vaccine with > 70% efficacy would have effectively stopped spread of COVID.
Actual vaccines came in at 80% to 90% efficacy, leading some politicians and medical people to proclaim total protection of vaccination (at least that was the simplistic message presented by the press; and maybe the simplistic message understood by those politicians).
But later variants of COVID are estimated to have R around 12.
1-1/R=1-1/12=0.91, so even a 90% effective vaccine would have trouble stopping the spread, even if everyone were vaccinated.
Vaccine efficacy drops significantly with new variants, so COVID is likely to become something like flu vaccination, where they vaccinate the vulnerable against the most common circulating strains.
Quote from: Bored Chemist, Paul Cotter
Smallpox, Polio...CovidA significant difference between Smallpox/Polio and COVID is that Smallpox & Polio only infect humans. That makes it easier to control.
COVID has infected rodents, domestic pets, and deer, suggesting that there will be animal reservoirs which will continue generating new variants, even after you have vaccinated all the human population.
Post by: alancalverd on 18/06/2023 00:00:01
Who expected it? You didFor the benefit of poor readers, I have emboldened and italicised two rather important words. The question wasn't "will it..." but "can it....."QuoteQuote from: alancalverd on 24/05/2021 15:29:45
Yes and yes, because herd immunity isn't the same as inherent tolerance or immunity. If 80% of the population is immune through vaccination or prior infection, the probability of anyone else being infected becomes very small (herd immunity) but those that are infected can indeed breed mutants.
Post by: set fair on 18/06/2023 01:03:33
Who expected it? You didFor the benefit of poor readers, I have emboldened and italicised two rather important words. The question wasn't "will it..." but "can it....."QuoteQuote from: alancalverd on 24/05/2021 15:29:45
Yes and yes, because herd immunity isn't the same as inherent tolerance or immunity. If 80% of the population is immune through vaccination or prior infection, the probability of anyone else being infected becomes very small (herd immunity) but those that are infected can indeed breed mutants.
But the "if" had already come true by the time you made your post - 80% seropositivity by early May 2021 ( see graph on page 37 https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1101870/vaccine-surveillance-report-week-35.pdf ) , the UK reached 95% seropositivity by week 41 2021 ( last sentence page 20 https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1025358/Vaccine-surveillance-report-week-41.pdf ) and there never was herd immunity and there were no new variants in the UK between when you posted and Omicron in december. In fact in october 2021 we reached record numbers of new cases.
Post by: alancalverd on 18/06/2023 12:13:08
( see graph on page 37and read the title and rubric. It shows that blood donors were either infected or vaccinated (Roche S assay) or infected (Roche N assay). As they were not a priority group for vaccination, it actually tells you nothing about vaccine takeup or effectiveness in the whole or the priority target population. Seropositivity tells you nothing about the infectivity of the subject, only that he is or has been infected or vaccinated.
Also worth questioning the validity of any extrapolation from a very self-selected group to the population as a whole. If there are roaming wolves or rampant viruses in the street, who is going to present himself in a public clinic as a blood donor for no reward? Not Joe Average,I feel.
We also know that neither vaccination nor infection completely prevents reinfection so my "if" can only be half true - you could vaccinate everyone but that wouldn't mean that everyone was immune.
Anyway we agree that the UK population never reached an acceptable level of herd immunity. Or have we? There are still sporadic cases but they don't make the headlines, which, as for the common cold, is probably the best working definition of herd immunity.
Epidemiology is not physics, with clear-cut numbers. At best, it's biochemistry with complicated pathways and fractional yields, and then you have to subtract a huge dose of psychology, politics and guesswork to decide whether your intervention is effective - assuming you have defined "effective". The only credible number is excess deaths.
Post by: Petrochemicals on 18/06/2023 16:38:05
For simple models, the proportion of the population that needs to be effectively immunized (meaning not susceptible to infection) to prevent sustained spread of the infection has to be larger than 1 - 1/R This is the so-called Herd immunity threshold or herd immunity level.This begins to sound as a retreat, but maybe it's because I'm simple. I believed what I was promised in the vaccine.
Post by: alancalverd on 18/06/2023 22:43:35
Post by: Petrochemicals on 24/06/2023 23:11:01
Citation needed. Who made that promise? Surely you are old enough not to believe a politician.The Lancet
Quote from: the Lancet, highly respected medical journal, awfully official, difficult to wriggle out of
vaccines were shown to have 94?95% efficacy in preventing symptomatic COVID-19
https://www.thelancet.com/journals/laninf/article/PIIS1473-3099(21)00075-X/fulltext#:~:text=vaccines%20were%20shown%20to%20have,the%20attack%20rate%20with%20placebo).
Post by: alancalverd on 25/06/2023 00:22:01
Post by: Petrochemicals on 25/06/2023 01:05:39
That's an experimental finding, not a promise.So the politicians you have conceded did say vaccines would be herd immunity, the medical journal states the vaccines will give herd immunity, and now for one night only Sir Patrick I know everything about corona Vallance states ;
Quote
And you?ll need very very high levels of population coverage ? 70% or more ? in order to get some degree of immunity across the whole population.https://www.gloucestershirelive.co.uk/news/uk-world-news/total-herd-immunity-would-require-4907184
I will concede that "some degree of immunity" may be indistinct, but if a used car salesman offered some degree of performance and the wheels fell off you may have reason to be aggrieved! At no level did the vaccines provide herd immunity as seen in measles, which if like the many corona vaccines, would see the population rife with the disease.
Post by: Petrochemicals on 25/06/2023 01:30:08
Quote from: itv news
Prof Van-Tam also told the panel it would also take a considerable amount of time for any herd immunity to kick in, since a large percentage of the population would need to be vaccinated for this to happen.https://www.itv.com/news/2020-12-02/covid-vaccine-professor-jonathan-van-tam-addresses-jab-safety-concerns-of-itv-news-panel-in-q-and-a
Post by: alancalverd on 25/06/2023 11:15:36
So the politicians you have conceded did say vaccines would be herd immunity,Quite possibly. But this is a science chatroom. Whatever Tory politicians say or do is intended to benefit themselves and their friends, at your expense, and need not be related to any actual facts.
Quote
the medical journal states the vaccines will give herd immunity,Citation needed, but
Quote
And you'll need very very high levels of population coverage ? 70% or more ? in order to get some degree of immunity across the whole population.is obvious. In the case of COVID, probably 90%, maintained for a couple of years.
Post by: Petrochemicals on 25/06/2023 15:02:49
Citation needed, but
Quote
we would expect 50 cases (99?95% of the population is disease-free, at least for 3 months).It's not exactly what happened in new Zealand.
In the case of COVID, probably 90%, maintained for a couple of years.You are probably thinking about eradication? As in small pox? There is no herd immunity presently from small pox in the populace. Which is why it is so perilous if a source emerged.
Post by: Petrochemicals on 25/06/2023 15:05:21
Post by: alancalverd on 25/06/2023 22:45:00
But yes, as the quotes espouse, herd immunity was supposed to be imbued to the populace.Supposed by whom? No scientist would make such a statement without lots of qualification (as Vallance and Van Tam stated) and so far you haven't even quoted a professional liar as making such a promise. It seems to be a figment of your imagination.
Post by: Petrochemicals on 26/06/2023 13:45:18
You must be winding me up. There is the already quotedBut yes, as the quotes espouse, herd immunity was supposed to be imbued to the populace.Supposed by whom? No scientist would make such a statement without lots of qualification (as Vallance and Van Tam stated) and so far you haven't even quoted a professional liar as making such a promise. It seems to be a figment of your imagination.
Quote
And you'll need very very high levels of population coverage ? 70% or more ? in order to get some degree of immunity across the whole population
And then the WHO, not the 60s band either!
https://www.who.int/news-room/questions-and-answers/item/herd-immunity-lockdowns-and-covid-19
Quote
Herd immunity against COVID-19 should be achieved by protecting people through vaccination
So there you are! Herd immunity vaccination. Didn't work, new Zealand tried it, Brazil now has a lower mortality rate than the UK, even though the ethnic make up is more vulnerable.
Screenshot_20230614_234924.jpg (253.25 kB . 1920x1200 - viewed 648 times)Post by: alancalverd on 26/06/2023 14:35:25
I could drive to Edinburgh without stopping if the road is clear and I have a full tank of fuel. So I set off with half a gallon of petrochemicals on a snowy day, and when we grind to a halt at Peterborough you complain "but you promised....."
I would understand your attitude if English were not your native language, or you were 8 years old, but I doubt that you meet those criteria. Oh, sorry, I mentioned criteria, which is a rude word.
Post by: Petrochemicals on 26/06/2023 16:57:50
You seem unable to distinguish between "should....if....." and a promise.You would make a very good politician, possibly tory, you may have been able to help out johnson. Or used car salesman.
I could drive to Edinburgh without stopping if the road is clear and I have a full tank of fuel. So I set off with half a gallon of petrochemicals on a snowy day, and when we grind to a halt at Peterborough you complain "but you promised....."
I would understand your attitude if English were not your native language, or you were 8 years old, but I doubt that you meet those criteria. Oh, sorry, I mentioned criteria, which is a rude word.
The who is espousing the vaccination programme to provide herd immunity. What you are trying to make a case for is "that every body should bare in mind it may not work", a post climax disclaimer!
Post by: alancalverd on 26/06/2023 17:42:43
The who is espousing the vaccination programme to provide herd immunity.Citation needed. WHO certainly promote vaccination for disease prevention, and has been very successful in doing so. But they are not so stupid as to suggest that you can achieve herd immunity in a short time with an inadequate uptake, a short period of effectiveness, and a rapidly evolving virus. Nor that herd immunity means 100% immunity of the entire herd.They know what it means even if you don't.
Did Loathsome Johnson ever make such a promise?
Post by: Petrochemicals on 26/06/2023 20:33:08
So the WHO are saying herd immunity? That is in fact proof of my point.The who is espousing the vaccination programme to provide herd immunity.Citation needed. WHO certainly promote vaccination for disease prevention, and has been very successful in doing so. But they are not so stupid as to suggest that you can achieve herd immunity in a short time with an inadequate uptake, a short period of effectiveness, and a rapidly evolving virus. Nor that herd immunity means 100% immunity of the entire herd.They know what it means even if you don't.
?
I. adequate uptake in New Zealand? I will grant you that the period of effectiveness is not long enough, ie nil.
I have given you the Who link. I have shown you the quote. There is no more I can do.
Post by: alancalverd on 26/06/2023 22:53:19
So the WHO are saying herd immunity?No. You assert that they are, but you have not shown any evidence to that effect. Here's what they actually wrote:
Quote
The percentage of people who need to be immune in order to achieve herd immunity varies with each disease. For example, herd immunity against measles requires about 95% of a population to be vaccinated. The remaining 5% will be protected by the fact that measles will not spread among those who are vaccinated. For polio, the threshold is about 80%. The proportion of the population that must be vaccinated against COVID-19 to begin inducing herd immunity is not known.
which, unlike your libellous assertions, makes sense.
Post by: Petrochemicals on 26/06/2023 23:07:03
Libelious?So the WHO are saying herd immunity?No. You assert that they are, but you have not shown any evidence to that effect. Here's what they actually wrote:QuoteThe percentage of people who need to be immune in order to achieve herd immunity varies with each disease. For example, herd immunity against measles requires about 95% of a population to be vaccinated. The remaining 5% will be protected by the fact that measles will not spread among those who are vaccinated. For polio, the threshold is about 80%. The proportion of the population that must be vaccinated against COVID-19 to begin inducing herd immunity is not known.
which, unlike your libellous assertions, makes sense.
Measles polio etc do not spread, small pox did not spread, due to the vaccine stopping spread. Corona did. You seem to have skirted around what the who said. As I have quoted before
Quote from: the WHO
Quote
Herd immunity against COVID-19 should be achieved by protecting people through vaccination
Man that is some libelous quoting.
Post by: alancalverd on 27/06/2023 08:02:22
Libelious?Libel: a published false statement that is damaging to a person's reputation; a written defamation.
You have libelled WHO. However in a science forum, I think this is a lesser offence than deliberately misrepresenting elementary epidemiology.
But being a generous soul, I'll have one more attempt at explaining the problem.
Smallpox is principally transmitted by prolonged mechanical contact with a symptomatic person. Therefore it can be controlled by quarantine and vaccination. Quarantine of actual and suspected carriers had been strictly imposed for centuries. After 200 years' development the vaccine was highly effective, and the virus seems to have been fairly stable. Elimination took 70 years.
COVID is an airborne infection transmitted by asymptomatic carriers. Quarantine is therefore difficult to impose except by 100% isolation of the asymptomatic population (i.e. everyone) which apparently is a crime against Yuman Rites. The vaccines developed within 6 months have limited duration of effectiveness, and the virus evolved rapidly. The herd declined to acquire immunity within 3 years.
Post by: evan_au on 27/06/2023 10:33:46
Quote from: WHO
The proportion of the population that must be vaccinated against COVID-19 to begin inducing herd immunity is not known.You can make some guesstimates based on:
- R0: The average number of other people who will be infected by one infected individual
- Vaccine Efficacy: The percentage of people who will be protected if they are given the vaccine. Call it E
The original Wuhan virus had R0 ≈ 2.5, and RNA vaccine efficacy E ≈ 90%.
- The minimum number to be vaccinated = 1-E/R0 ≈ 1-0.9/2.5 = 64% of the population
- That is why early predictions said that if most people had the vaccine, it would protect the population as a whole against the spread of the virus
Two years later: It is thought that some of the more recent COVID variants have R0 ≈ 12.
- Against these variants, the original vaccine against Wuhan strain had efficacy E ≈ 40%.
- The minimum number to be vaccinated = 1-E/R0 ≈ 1-0.4/12 = 97% of the population
- Even well-vaccinated countries have trouble meeting this high target for vaccination
- Throw in the fact that vaccine protection declines with time, so E reduces significantly 5 months after previous vaccination or exposure
Which is why there are now bivalent vaccines available, which provide a higher efficacy against the recent variants
- And people are encouraged to get a booster every 6 months
- And still wear a mask if there is an outbreak in your area.
The COVID emergency may be over, but COVID is not over.
- A significant difference between COVID and smallpox is that smallpox only infects humans
- COVID infects many mammal species, so there is an animal reservoir of the virus that will continue mutating, and potentially jumping back into the human population. That makes elimination practically impossible with our current technologies.
Post by: alancalverd on 27/06/2023 10:50:00
Unfortunately sensible overreaction does not include giving taxpayers' money to Tory party donors for faulty or nonexistent goods and services, defining a substantial meal as one that includes lettuce, or discharging infectious patients into nursing homes.
Having missed an open goal in Brexit negotiations, HM Government scored an own goal by apparently trying to reach a compromise with a virus!
Post by: Petrochemicals on 27/06/2023 16:16:15
Quote from: Petrochemicals on Yesterday at 23:07:03[Quote from: the WHO]
Libelious?
Libel: a published false statement that is damaging to a person's reputation; a written defamation.
You have libelled WHO. However in a science forum, I think this is a lesser offence than deliberately misrepresenting elementary epidemiology.
Herd immunity against COVID-19 should be achieved by protecting people through vaccination
[/quote]
On that basis you are libeling me!
Post by: alancalverd on 27/06/2023 17:41:48
Persons of a scientific mind will have read the entire opening paragraphs of the WHO statement
Quote
'Herd immunity', also known as 'population immunity', is the indirect protection from an infectious disease that happens when a population is immune either through vaccination or immunity developed through previous infection. WHO supports achieving 'herd immunity' through vaccination, not by allowing a disease to spread through any segment of the population, as this would result in unnecessary cases and deaths.
Herd immunity against COVID-19 should be achieved by protecting people through vaccination, not by exposing them to the pathogen that causes the disease. Read the Director-General?s 12 October media briefing speech for more detail.
and not simply picked a few words out of context to encourage the Trumpians and Johnsonians of this world.
Post by: Petrochemicals on 27/06/2023 20:43:09
Post by: alancalverd on 28/06/2023 07:53:03
If they where just pointing out the obvious they would have no position.But as the foregoing argument shows, it was not obvious to an intelligent, well informed and thoughtful person like yourself, so they had to say it, even if idiots chose to ignore the truth.