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60-70% for herd immunity is pretty much a known. Do you have any link to something saying some people are naturally immune to the novel Covid19? I have seen nothing like that in any science article.
What I know is math and stats. Most of my sources are from Swedish researchers, mostly they are university professors, some work for the govt. 60 to 70% of random people would be needed for the R0 of 2.6 to drop below 1. That's math.
What changes the herd immunity %, as explained in that article (yes not peer reviewed, it just was published Tuesday! by those professors at University of Stockholm), is if there are innate immune people in the population and if different people are more susceptible than others. That's still math, if such people exist.
Do such people exist? In comes the stats: Yes! Every place in the world with cases has a % of people who should have been infected but weren't. Diamond Princess for starters. That aircraft carrier. Schools that had infected kids, even nursing homes and prisons don't seem to get past a 75% infection rate. Never. They must exist if this is true in every case, no? Statistically its impossible otherwise. They are looking at why. I don't know, I won't pretend to be able to guess why. It does tend to be more in the younger population (children rarely have passed it to other children).
If innate immunity is around 30%, we only need 30% or less to be infected to reach herd immunity. Why else is Stockholm's case count declining? Nobody seems to be able to answer that.
What I know is math and stats. Most of my sources are from Swedish researchers, mostly they are university professors, some work for the govt. 60 to 70% of random people would be needed for the R0 of 2.6 to drop below 1. That's math.
What changes the herd immunity %, as explained in that article (yes not peer reviewed, it just was published Tuesday! by those professors at University of Stockholm), is if there are innate immune people in the population and if different people are more susceptible than others. That's still math, if such people exist.
Do such people exist? In comes the stats: Yes! Every place in the world with cases has a % of people who should have been infected but weren't. Diamond Princess for starters. That aircraft carrier. Schools that had infected kids, even nursing homes and prisons don't seem to get past a 75% infection rate. Never. They must exist if this is true in every case, no? Statistically its impossible otherwise. They are looking at why. I don't know, I won't pretend to be able to guess why. It does tend to be more in the younger population (children rarely have passed it to other children).
If innate immunity is around 30%, we only need 30% or less to be infected to reach herd immunity. Why else is Stockholm's case count declining? Nobody seems to be able to answer that.
The Rt is important in determining how many people need to clear the virus for herd immunity. At an Rt of 1.3 (everyone wearing masks and practicing social distancing, but business open... hopefully) you can achieve herd immunity and have the virus fade into the background with about 40% of the population infected.
However, at an Rt of 2.0 or 2.5, you need 65-75% of the population to clear the virus. So if we have seasonal forcing (Sunlight, vitamin D, whatever) holding the Rt down during the summer, we could expect to see another wave in the fall, even if we get to "herd immunity" in July or August (which I think is likely, considering how the lockdowns are falling apart pretty much everywhere, after one or two measly months!)
The Rt is important in determining how many people need to clear the virus for herd immunity. At an Rt of 1.3 (everyone wearing masks and practicing social distancing, but business open... hopefully) you can achieve herd immunity and have the virus fade into the background with about 40% of the population infected.
However, at an Rt of 2.0 or 2.5, you need 65-75% of the population to clear the virus. So if we have seasonal forcing (Sunlight, vitamin D, whatever) holding the Rt down during the summer, we could expect to see another wave in the fall, even if we get to "herd immunity" in July or August (which I think is likely, considering how the lockdowns are falling apart pretty much everywhere, after one or two measly months!)
It's an annoyingly slippery sliding scale.
If masks and social distancing get you down to 1.3, then a little bit of contact tracing even with inadequate tests might get you down closer to 1.0, in which case you can get by with even less immunity.
The Rt is important in determining how many people need to clear the virus for herd immunity. At an Rt of 1.3 (everyone wearing masks and practicing social distancing, but business open... hopefully) you can achieve herd immunity and have the virus fade into the background with about 40% of the population infected.
However, at an Rt of 2.0 or 2.5, you need 65-75% of the population to clear the virus. So if we have seasonal forcing (Sunlight, vitamin D, whatever) holding the Rt down during the summer, we could expect to see another wave in the fall, even if we get to "herd immunity" in July or August (which I think is likely, considering how the lockdowns are falling apart pretty much everywhere, after one or two measly months!)
It's an annoyingly slippery sliding scale.
LOL! Yes!
It would be helpful if people could just realize that even with all the technology we have the numbers people want are just not available, will not be available until the epidemic is over, and then will be estimates.
1. There may be some people who are genetically resistant to infection with SARS-CoV-2, just as there are for HIV and norovirus. Some researcher is probably working on that now, but it is not likely to be 20 to 30% of the population. Resistance is not the same as immunity. To become immune you have to be infected or vaccinated.
The number needed to be immune depends on the R0, so it is possible to estimate the threshold needed for herd immunity. This article takes into consideration variations in susceptibility:
2. People with SARS-CoV-2 do make neutralizing antibodies. That is why convalescent plasma from recovered patients is being used to treat sick patients. It will be a while before enough people are tested to be able to estimate how many have been infected.
1. Symantics. I was describing innate, natural immunity, which is the same thing as immune for the purposes of herd immunity (which isn't immunity in the strict sense, its the inability to transmit it that counts).
2. They usually do yes, but it hasn't been detected 100% of the time. We don't know yet whether children or young adults who get the virus but don't know it activate the immune response for antibodies. They might be shutting it down with T cells to be "resistant".
Immunity is only acquired when an infection induces the specific immune response. Cells infected by virus die and are transported to lymph nodes and specific immune responses start against different structures of the virus (we make no immune response to our own cells for which we are tolerant of). T cells with specificity for virus structures proliferate, as do B cells specific for viral structures. After a few weeks you have large amounts of ready, active, alert B and T cells with specificity against different virus structures. The B cells mature into plasma cells that form antibodies. Those mostly migrate to the nose and intestines and act as "neutralizing" antibodies.
If masks and social distancing get you down to 1.3, then a little bit of contact tracing even with inadequate tests might get you down closer to 1.0, in which case you can get by with even less immunity.
That's the hope. But, honestly, I don't think we're going to be able to achieve 1.3, even with contact tracing and better testing, after lockdowns crumble.
I think everyone is going to get back out there. Contract tracers are going to do a half-assed job, where the states even bother to pay for them, and everyone is just going to be business as usual for a month or two with an Rt near 2.0 but hidden by the long latency of the virus and asymptomatic transmission. Then we'll have a scary crisis in June-July, then it will all be over thanks to our natural biology, with a shell-shocked public wondering how the hell it got so bad and why all our local hospitals had to stack bodies on the sidewalks.
Yeah, I am pessimistic. But look at Sweden. They seem to be doing okay, so maybe.
Then again, Sweden is much less dense than most of the United States. Maybe they also don't do dumb **** like nail salons and (unmasked) bible study groups, hot yoga, etc.
What I know is math and stats. Most of my sources are from Swedish researchers, mostly they are university professors, some work for the govt. 60 to 70% of random people would be needed for the R0 of 2.6 to drop below 1. That's math.
What changes the herd immunity %, as explained in that article (yes not peer reviewed, it just was published Tuesday! by those professors at University of Stockholm), is if there are innate immune people in the population and if different people are more susceptible than others. That's still math, if such people exist.
Do such people exist? In comes the stats: Yes! Every place in the world with cases has a % of people who should have been infected but weren't. Diamond Princess for starters. That aircraft carrier. Schools that had infected kids, even nursing homes and prisons don't seem to get past a 75% infection rate. Never. They must exist if this is true in every case, no? Statistically its impossible otherwise. They are looking at why. I don't know, I won't pretend to be able to guess why. It does tend to be more in the younger population (children rarely have passed it to other children).
If innate immunity is around 30%, we only need 30% or less to be infected to reach herd immunity. Why else is Stockholm's case count declining? Nobody seems to be able to answer that.
Things aren't going so well in Sweden these days. Not sure I'd be so accepting of their information. They have a higher death rate than we do. https://coronavirus.jhu.edu/data/mortality
Quote:
Originally Posted by wac_432
That's the hope. But, honestly, I don't think we're going to be able to achieve 1.3, even with contact tracing and better testing, after lockdowns crumble.
I think everyone is going to get back out there. Contract tracers are going to do a half-assed job, where the states even bother to pay for them, and everyone is just going to be business as usual for a month or two with an Rt near 2.0 but hidden by the long latency of the virus and asymptomatic transmission. Then we'll have a scary crisis in June-July, then it will all be over thanks to our natural biology, with a shell-shocked public wondering how the hell it got so bad and why all our local hospitals had to stack bodies on the sidewalks.
Yeah, I am pessimistic. But look at Sweden. They seem to be doing okay, so maybe.
Then again, Sweden is much less dense than most of the United States. Maybe they also don't do dumb **** like nail salons and (unmasked) bible study groups, hot yoga, etc.
Less dense? 85% of Swedes live in cities, mostly in the southern part of the country. I'd be willing to bet the farm they do nail salons, hot yoga, etc and/or the equivalent. Probably not Bible studies. https://studyinsweden.se/why-sweden/...-about-sweden/
That's the hope. But, honestly, I don't think we're going to be able to achieve 1.3, even with contact tracing and better testing, after lockdowns crumble.
I think everyone is going to get back out there. Contract tracers are going to do a half-assed job, where the states even bother to pay for them, and everyone is just going to be business as usual for a month or two with an Rt near 2.0 but hidden by the long latency of the virus and asymptomatic transmission. Then we'll have a scary crisis in June-July, then it will all be over thanks to our natural biology, with a shell-shocked public wondering how the hell it got so bad and why all our local hospitals had to stack bodies on the sidewalks.
Yeah, I am pessimistic. But look at Sweden. They seem to be doing okay, so maybe.
Then again, Sweden is much less dense than most of the United States. Maybe they also don't do dumb **** like nail salons and (unmasked) bible study groups, hot yoga, etc.
1st of all, I hope you're right about the vitamin D, seasonality thing. If so, we should all be getting our Vitamin D levels up. I will be popping a 400iu until this is over. There sure seems to be a lot of data pointing towards it.
Sweden is doing okay outside of the nursing homes. All of the following has declined there since mid Aprilish: daily deaths, ICU admission rates, confirmed cases.
They send their kids to school 5 days a week. Most service businesses are open. Gyms are open. NO masks. Bigger crowded things are closed and people are encouraged to work from home, and not congregate. I want to do their level of "lockdown" after we get another month of data from there first.
They did report 147 deaths yesterday but it was mostly backlogs. Of those, 120 were over 80 and 52 were over 90. Their mortality rate is about the same as Pennsylvania and you don't hear about Pennsylvania being an especially hard hit state.
Actually the protests are fueled by fears of a mandatory vaccine. They are saying the pro vaccine should show how strong their faith in vaccines is & volunteer to take the shot.
What I know is math and stats. Most of my sources are from Swedish researchers, mostly they are university professors, some work for the govt. 60 to 70% of random people would be needed for the R0 of 2.6 to drop below 1. That's math.
What changes the herd immunity %, as explained in that article (yes not peer reviewed, it just was published Tuesday! by those professors at University of Stockholm), is if there are innate immune people in the population and if different people are more susceptible than others. That's still math, if such people exist.
Do such people exist? In comes the stats: Yes! Every place in the world with cases has a % of people who should have been infected but weren't. Diamond Princess for starters. That aircraft carrier. Schools that had infected kids, even nursing homes and prisons don't seem to get past a 75% infection rate. Never. They must exist if this is true in every case, no? Statistically its impossible otherwise. They are looking at why. I don't know, I won't pretend to be able to guess why. It does tend to be more in the younger population (children rarely have passed it to other children).
If innate immunity is around 30%, we only need 30% or less to be infected to reach herd immunity. Why else is Stockholm's case count declining? Nobody seems to be able to answer that.
Not just Stockholm, but NYC. 2 weeks ago, 24.7% of the population had been infected (according to antibody studies). It's undoubtedly higher now-and daily deaths are dropping-quickly. Rt for NY state is .79 currently. I haven't read of any new, enhanced efforts by NY that would explain a change. Well, other than no longer forcing nursing homes to take covid-positive patients.
Quote:
Originally Posted by wac_432
The Rt is important in determining how many people need to clear the virus for herd immunity. At an Rt of 1.3 (everyone wearing masks and practicing social distancing, but business open... hopefully) you can achieve herd immunity and have the virus fade into the background with about 40% of the population infected.
However, at an Rt of 2.0 or 2.5, you need 65-75% of the population to clear the virus. So if we have seasonal forcing (Sunlight, vitamin D, whatever) holding the Rt down during the summer, we could expect to see another wave in the fall, even if we get to "herd immunity" in July or August (which I think is likely, considering how the lockdowns are falling apart pretty much everywhere, after one or two measly months!)
In 48 states Rt is under 1, and in some cases significantly so. And has been for some time. The 2 where it's not are just barely over.
I'd really like to understand what Montana is doing that is working so well. Their lockdown was no "harder" than many surrounding states. Yes, they are a rural state, but so are many others. Yet their Rt is at .41. The next lowest state is at .69.
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