A 90 year old woman in a nursing home is not spreading COVID. Wouldn't it make more sense to give this to people who are most at risk of spreading it, not dying from it? Why wouldn't we go at the root cause of the pandemic; young healthy asymptomatic spreaders?
Just as a side note, asymptomatic spread is a contested topic. If asymptomatic spread were a major driver of infection, this would be the first respiratory virus to work that way.
I'm not aware of stats relating to how many asymptomatic individuals go on to develop full blown symptomatic Covid-19. My assumption is that testing PCR positive while remaining asymptomatic the entire time is by far the most common experience.
Of course, whether you go on to develop symptoms or not, its still highly pertinent information if asymptomatic spread is not a major driver of infection. As long as you self isolate upon symptom onset that should be enough. It does call into question whether isolating the apparently healthy is an evidence-based public health policy intervention though.
Truly asymptomatic spread is not a major driver of infection. There are been some major public relations problems when an organization said this, and were mistaken to mean pre-symptomatic, but the science is pretty clear.
We used to think true asymptomatic infections (never develop any symptoms but test positive) were ~50% of those infected. More recent research puts it at closer to ~20%. Again, some reporting bungled this by reporting studies from controlled populations (like a cruise ship) before they knew if cases were asymptomatic or pre-symptomatic, causing people to quote the number as the former, when it was really a mix.
COVID spreads like wildfire by pre-symptomatic people. There are mountains of evidence to support this. Spread by asymptomatic people is speculation.
> Of course, whether you go on to develop symptoms or not, its still highly pertinent information if asymptomatic spread is not a major driver of infection.
Not sure, but I think you may be using the word "asymptomatic" to denote pre-symptomatic in this sentence.
> As long as you self isolate upon symptom onset that should be enough.
If a person has no symptoms, I think it is reasonable to say they are "asymptomatic".
There is absolutely a difference between 'yet to have' and 'never will have' but I think it is potentially confusing to attempt to delineate between asymptomatic and "pre-symptomatic".
The main concern with messaging that causes confusion in this regard is that a superficial reading of "asymptomatic doesn't spread virus" would imply that if you aren't symptomatic, you aren't a danger.
Every symptomatic person was asymptomatic before they started getting their first symptoms. It might have been few days that they already had the virus on their mucus membranes.
I made a new point, so am I missing my own point? Confused.
> Obviously if people were only contagious if showing symptoms, the pandemic wouldn't be.
I don't think that is obviously the case at all. It would have to be proved. The dominant vectors of contagion are not yet well understood - we could be dealing with very highly infectious airborne virus, that is capable of spreading widely from a relatively small number of symptomatic and pre-symptomatic super spreaders.
The fact remains that current public health interventions orientate around isolating individuals whether they are symptomatic, asymptomatic or paucisymptomatic. Moreover, to greater and lesser degrees we also isolate the healthy, assuming them to be asymptomatic in an abundance of caution. Considering the negative non-covid related knock on effects of these policies its at least worth investigating isn't it?
> we could be dealing with very highly infectious airborne virus, that is capable of spreading widely from a relatively small number of symptomatic and pre-symptomatic super spreaders.
The calculated R0 does not support this theory. Measles works this way. R0 for Measles is > 10
> that current public health interventions orientate around isolating individuals whether they are symptomatic, asymptomatic or paucisymptomatic
Everywhere, the restrictions are higher if you were tested and/or is suspected of having Covid. Of course a lot of people DNGAF about the restrictions, which is part of the problem.
Again, if your theory that people showing no symptoms do not transmit the disease then it should be super easy to go around and start finding people spreading it. But it isn.t
I followed the New Zealand press conferences very closely and so often the initial story was this person had no symptoms, total surprise to them that they had the virus, and then a day later oh, well, actually they did have some symptoms but they didn't realise it was COVID-19...
People will say to themselves well, it's just a cough right? Just a cough. I can't have COVID-19 that's something other people get, those people are sick but I'm healthy, this is just a cough. And that allows the virus to spread.
> They are either paucisymptomatic (you have mild symptoms - maybe too mild to notice)
Or you notice them but because they also match symptoms of colds and allergies, and you’ve been getting them on and off for months, you assume they aren’t COVID.
I don’t think there has been an interval longer than a week since February during which I didn’t have at least a couple symptoms that could have been COVID.
I’ve not had the taste/smell loss, and all my contact with other people has been masked and brief, and I’m in an area where spread has been low, so I’ve probably not had it, but I wish we had widespread cheap testing so I could know.
> Or you notice them but because they also match symptoms of colds and allergies, and you’ve been getting them on and off for months, you assume they aren’t COVID.
Exactly. I have occasionally runny nose combined with sporadic sneezes and coughs pretty much every winter. If someone like my had so "mild" COVID symptoms they would consider themselves asymptomatic (paucisymptomatic?), and rightfully so. (My actual COVID symptoms were not as mild, but not very serious either.)
> I don’t think there has been an interval longer than a week since February during which I didn’t have at least a couple symptoms that could have been COVID.
It's remarkable the number of people anecdotally reporting similar symptoms - often out of character for otherwise robustly healthy individuals. I'm guessing some sort of psychosomatic response to the year's stresses.
I have been having the same, but the main reason why I notice it now is that every time I have any symptom, even the mildest of them, I take notice and consider the possibility of Covid, whereas in past years I would forget about them if even notice at all.
For context, I'm a fairly healthy individual who hasn't seen a GP or other medical doctor in at least a couple years, probably longer. Last time I've been to one was because of exercise-related injuries.
That being said it seems the most specific symptom is loss of smell/taste so unless you have that it's probably something else (disclaimer: not a doctor and this is not medical advice)
12 months in, I'd say we can already claim it more than "reeks": it is full-blown intellectual dishonesty. Viral load peeks before symptoms onset, we have quite a few case studies of transmission, but these people apparently want some dozens of RCTs before admitting it.
In Ontario (as elsewhere), there's been a giant ramp up in cases since the start of September, with an accompanying discussion about whether or not reopening schools is the cause. But a recent testing blitz at a single Toronto school uncovered 26 infected individuals scattered across 18 classrooms:
Still not obvious one way or the other about whether these students and staff are spreading it amongst themselves or if they all got it from other symptomatic cases in the community and independently brought it to school with them. But either way, it's sobering how much of it is going undetected.
"Wouldn't it make more sense to give this to people who are most at risk of spreading it, not dying from it?"
It wouldn't make any sense at all. The reason is that not only do older people have a greater risk of dying from Covid, they also have a much higher risk of being hospitalized[1], and remember the justification for the extreme measures we've taken and continue to take is the fear we will overwhelm our health care systems.
They looked at that, and modelled what would save the most life-years based on limited speed that the vaccine can be deployed, how well the vaccine works in stopping bad effects (i.e. death), and how well it works in stopping spread.
> JCVI has considered a number of different vaccination strategies, including those targeting transmission and those targeted at providing direct protection to persons most at risk. In order to interrupt transmission, mathematical modelling indicates that we would need to vaccinate a large proportion of the population with a vaccine which is highly effective at preventing infection (transmission). At the start of the vaccination programme, good evidence on the effects of vaccination on transmission will not be available, and vaccine availability will be more limited. The best use of available vaccine will also, in part, be dependent on the point in the pandemic the UK is at. Given the current epidemiological situation in the UK, all evidence indicates that the best option for preventing morbidity and mortality in the initial phase of the programme is to directly protect persons most at risk of morbidity and mortality.
It's not yet known whether the Pfizer vaccine prevents an infected person from transmitting the infection to other people [1]. But there is robust evidence that is does prevent an immunised person from becoming ill.
Could someone please explain how this can be the case? I understand the vaccine works by stimulating antibody production, which prevent you from becoming ill by binding to the virus and disabling it should it enter your system. How then could the virus be spread further if it's already been disabled?
Virus can infect cells in areas that are difficult to reach for immune system - epithelial cells lining the nasal mucosa for example - but they still would produce viral particles that could be sneezed on someone else.
Indeed this paper found association between viral load and symptoms - hospitalized patients are shedding less virus
Different tissues are protected by different types of antibodies. A vaccine injected subcutaneously will mostly induce an IgG response, a type of antibody present in blood and extracellular fluid. This could still possibly allow a virus to infect mucous membranes, which rely on a different type of antibody, sIgA[0], to protect them. If this is the case, you could be protected from having a serious systemic infection, but could still suffer a mild upper respiratory infection, and be infectious until the immune system mounted defense in the mucous membranes.
Some flu vaccines come in the form of a nasal spray, which does induce an IgA response. I don't know why COVID vaccines are administered parenterally instead, I'm sure there are good technical reasons. Given the virus's possible neurological involvement, maybe it's a bad idea to deposit it so close to the olfactory bulb.
The vaccine teaches your immune system to respond to a particular protein that surrounds the virus. If you contract the virus you are still infectious until it can kill all of the virus. The time between the immune response and OG infection can mean the virus has time to replicate and spread/ be shed I’m guessing.
There is the virus replicating itself in a body, which leads to the body being able to spread the virus to others. And there is the body getting sick. The second often follows the first, but the two are not necessarily connected, which is proven by asymptomatic spreaders. In the vaccine phase 3 tests, it was only determined whether people get sick, and the vaccine was found to prevent 95% of people from getting sick. It was not tested whether the viral load in vaccinated people who don't get sick, but still had virus exposure, was high enough for a real likelihood of transmission to others. This now results in those warnings regarding potential transmission even through vaccinated people: scientifically that's a possibility that hasn't been ruled out.
However, the science is the easy part here. It gets complicated once politics comes into play. Pretty much all scientists I've spoken or listened to say that they assume that the spread will most likely be at least severely limited through the vaccines. That's because they don't have any other explanation than a reduced viral load that could explain how the vaccines actually work in preventing sickness, and a reduced viral load would also mean a reduced spreading capability. However, not knowing something does not mean it can't exist: it is not impossible for there to be some unknown way in which these vaccines may potentially prevent sickness without also limiting viral spread. And scientists usually want to be scientifically correct, so they don't go out and declare something as fact that they just carefully "assume" to be the case.
This "known unknown" of effectiveness in limiting viral spread is now actively being used by politics, especially those people coordinating protective measures in governments, as a convenient escape hatch out of a problematic situation. That situation is: how do you explain to someone who just got vaccinated that he/she should still adhere to all the protective measures like universal mask-wearing and limiting personal contacts? Because even though there are rational reasons for doing so (first, the vaccines need two shots and some weeks of time to actually build up protection, and second, if a significant portion of the populace is exempt from all the protective measures and their burdens, this incentivizes the remaining, non-vaccinated part to also "exempt themselves", because constraints enforced on all citizens are much easier to follow than constraints only enforced on half of all citizens) there will be a strong impetus within each individual to not follow protective measures and rules anymore, once vaccinated and thus "protected" from the virus. And besides that psychological effect there's the overarching problem of the constitutional impossibility of enforcing wide-ranging limitations on constitutional rights onto people that is not justifiable anymore, once an individual in question can provably no longer spread the virus. Because of all of this, politicians (rightfully) fear the situation that we're going to be in in a few months time, when a significant part of the populace, but not enough for herd immunity, is already vaccinated. An assumption of a possibility of transmission even with vaccination is a godsend in that situation.
Possible "reduced viral load" by those who are vaccinated simply doesn't mean that that load is below the threshold which makes somebody not infectious. In practice, it could, for example, mean that if such persons spend two hours in the room with you they can still transmit the virus to you, whereas the non vaccinated person with the virus would transmit to you in 15 minutes. So you can't just claim that a person is 100% safe because the load is just "reduced."
Additionally, for the immune system to respond, the infection has to happen first -- the virus has to spread through the cells of your body. We already know that the people are indeed infectious before their immune system response makes the symptoms. The delay in response has to exist even among the vaccinated people.
So what is sought after is a proof of sterilizing immunity, and there's no such still. I've read that the UK plans to evaluate the evidence for that in the following months by tracking the people who get the vaccine, which sounds good.
There is no threshold that makes people non-infectious. Or there is, and it is zero. Because even a single virus instance can potentially infect someone else. It is extremely unlikely to happen, but not impossible.
Because of this, for practical purposes, you either have to arbitrarily set a threshold at which someone is considered non-infectious, ignoring that it is not impossible for that person to infect someone. Or you have to stop talking in absolutes entirely and just talk about probabilities.
When taking about probabilities, one usually can recognize a reasonable threshold. In practice we do exactly that with most of the medicine: there could be some small chance that somebody can have health problems because his body responds unfavorably to the medicine, but if that chance is small enough it is considered acceptable when the potential benefits overweight the potential loss when the medicine is not used, its use is allowed. If the chance is big enough (i.e. potentially too many people will be affected) such a medicine is not allowed to be used, at least with the affected group of people.
The same is with the possibility that a vaccinated person infects somebody else. There is some point behind which it could be said that some vaccine has "sterilizing immunity" even if some small level of viruses could be present somewhere. For the current vaccine, the question is if the viral load in some point after the infection is decreased at all, and if it is, how much.
At the moment, however, it's simply not known if, in this case, Pfizer vaccine provides sterilizing level of immunity, if, then when, and in which percentage of the vaccinated. At the moment more or less we just know that the vaccinated are less probable to develop symptoms. Efficacy of 95% here means only one of 20 vaccinated develops symptoms when exposed to the virus, so we know that it's also probable that at least 1 in 20, even after being vaccinated, could be able to infect somebody else while being in the "pre-symptomatic" phase (as it is believed by the researchers that one transmits the virus before one's symptoms starts). We also believe that asymptomatic are also able to transmit. We don't know how much the vaccine affects the transmission that could occur when a vaccinated person is exposed to an infected one, and then later comes in close contact with other unvaccinated persons.
You are asking why an already infected person who receives the vaccine may still be able to spread it? The virus is still able to spread while the body fights it. In fact I'm not even sure there is a significant advantage of giving the vaccine to someone who already has the virus (as after all the vaccine teaches the body what the virus looks like and therefore how it can be tackled). This specific vaccine looks as if it simulates certain aspects of the virus, therefore not entirely necessary for someone who already has the virus I believe. But yeah - it's not like you get jabbed and you have instant immunity. Your body needs to learn to fight it, and then actually fight it - and if you already have it you are still infectious during this period.
No, you do, because no matter the age, the family members still want to have a chance of survival of their loved one. My distant relative (70 year old) was in ICU for 30 days, and on ventilator for 14 days. Yes, that is a very long time for ventilator usage, and every day more on a ventilator increases the death rate probability percentage.
At the age of 90, your lungs are too fragile to be put on a ventilator. It was one of the reasons academics overestimated the number of ventilators required for COVID.
its really not that simple, it turned out that the stats we were working from were wrong (well done china...) but also ventilators are not great for covid patients. Its much better to slap them with oxygen.
Of course they do, as long as there's a bed available. Especially with Covid. No hospital wants to be the one that denied a patient an available ICU bed.
Why not? She could contract it from a caretaker or visitor, and then spread it to the next caretaker who spreads it further.
One advantage of immunization in nursing homes is also that they can now take visitors more liberally.
Anecdotal, but several "super spread" type events near me were nursing homes. Makes some sense as there are a lot of communal facilities. People cross paths a lot, and several shifts of employees are in and out.
The uk is vaccinating according to risk of death, and risk of occupying a hospital bed first. Not the risk of catching or passing it.
THe big concern in this pandemic has been hospital usage. once your hospital is full everyone starts dying not just covid patients. We were about two/four weeks away from collapse in london in april.
As a standard, the UK makes medical decisions based on QALYs saved (quality-adjusted life years).
Although you can argue that keeping hospital beds free saves a lot of QALYs, it's harder to argue that care homes have a lot of QALYs to save.
And, it's not obvious that care home patients are the first to occupy hospital beds (I'm unsure about it); care home patients with COVID have tended to die in their care home.
> it's harder to argue that care homes have a lot of QALYs to save.
Not true at all. They may have fewer life years left, but they're orders of magnitude more likely to die from Covid, so preventing a Covid case in this population actually saves more QALYs than preventing a case in a younger healthy person, statistically speaking.
The vaccine wasn't tested for reducing spread - it was only tested for preventing symptomatic illness. We don't know yet if vaccinated people exposed to covid can spread it to others even if they don't get sick. Therefore we base our vaccination protocols on something the vaccine is proven to do, not something it might do hypothetically.
I wouldn't go that far. But I'd say they're doing their best with what they do know, which is going to be more comprehensive than "some guy on the Internet".
It doesn't mean they're right, or even that they're all in agreement on the best course. But they're tasked with making a decision that absolutely has to be made right now, and can't wait on getting a complete picture.
The first phase isn't to stop the spread. The initial pool of vaccinations is to lower the strain on healthcare infrastructure. Older patients are at more risk of requiring hospital stays + ICU stays.
People in homes are possibly primary vectors of spread, especially during the early days because they catch it so easily and are around others who catch it easily.
Also, the workers in the homes are put at significant risk due to this as well.
Vaccination also prevents catching it, which prevents dying from it, which this age group is much at risk at even without prior complications.
There is a heck of a lot more people who are at risk of being superspreaders, not even mentioning the huge number of middle aged people going to protests against a diseases existence. You won't get those people vaccinated. They will massively contribute to the spread.
Additionally, vaccinating risk groups in the high age category first lets you spot complications with the disease more early and it's ethically somewhat better to risk long-term vaccination issues with 90+ year olds than 20+ year olds, as one of these groups will have to suffer the consequences for a shorter time. It may sound harsh to make comparisons like that but you'll have to make decisions like that in a medical environment.
> Wouldn't it make more sense to give this to people who are most at risk of spreading it, not dying from it?
No, it makes sense to give this to people who are most at risk of spreading it to people who are most at risk of dying from it. Thus anyone in and around aged care.
isn't this where most of the fatalities are happening? isnt the handling of elderly covid patients the reason a lot of people are unhappy with Cuomo and others because they turned retirement homes into morgues?
I believe this was the case at the start, I'm not sure if this is the case now however. Deaths have only recently arrived at where they were at the first peak in the US, my impression was this was because it was a less vulnerable population being infected.
While I would certainly hope that it prevents spread too, I believe that the vaccine is only proven to prevent Covid-19 (the disease), and not to prevent the spread of SARS-CoV-2 (the virus that causes it).
I wouldn't be surprised if there was a small political motivation here too - the gov were heavily criticized for their terrible handling of covid in care homes, with an older voter base they might want to be seen to be doing right by the care homes this time around
Nonsense. Every country I've heard about is prioritizing nursing home residents, and few of them received the level of criticism that the UK did regarding nursing home residents.
I think there is an understandable political element to this, in that people want to see a reduction in the death rate from Covid-19 and politicians are judged on the number of deaths. So vaccinating those most likely to die makes perfect sense as it'll have most impact on death rates and therefore politicians' reputations.
I believe the vaccine has not been showed to reduce transmission, it's been shown to reduce impact, i.e. she's less likely to die if someone visits her, so great for her, and her families, well-being.
If it reduces impact it also reduces impact of transmission because the patient has lower viral load. Masks have to same effect, although to a lesser degree (and obviously a different mode of operation).
