How might Covid vaccines reduce mortality?
There are two possible mechanisms, thoughtfully explained in a thorough review and a recent article on Brownstone: Covid vaccines might reduce the risk of infection, or reduce the risk of death — if infected, or both. We can explain the mechanisms in words, with reference to ‘marginal and conditional probabilities’, or we can depict them in a causal diagram — a powerful methodological tool.
The first mechanism is simple: If a Covid vaccine reduces the risk of infection, it will also reduce the risk of death, because there is no doubt that getting infected increases the risk of death. Theoretical exceptions aside, if A affects B, and B affects C, then A affects C.
What if A does not affect B? What if a Covid vaccine does not reduce the risk of infection? Then it cannot reduce the risk of death through this mechanism. The causal chain does not exist. A link is broken.
By now we know that Covid vaccines appear temporarily to increase the risk of infection, and any subsequent benefit is nullified within months, if not turned again into harm (negative vaccine effectiveness). Therefore, according to the first mechanism, there is a short period when a Covid vaccine increases the risk of death, a limited period (a few months) when it decreases the risk of death, and a later period when the effect is null at best.
The second mechanism is more complicated. One aspect was explained in the Brownstone article and is related to a causal concept called ‘effect modification’. Like numerous epidemiological concepts, there are layers of complexity below superficial simplicity. I will keep it simple.
When two causes — Covid vaccine and Covid infection — operate on a single outcome (death), we may ask two causal questions:
- What is the effect of a Covid vaccine on the risk of death — if infected?
- What is the effect of a Covid vaccine on the risk of death — if not infected?
The second question is asking about vaccine-related death, the worst adverse effect. (A vaccine can be a cause of death even when someone is infected, but that’s another issue.)
Theoretically, the two types of effect could be different, in any possible way: magnitude and direction. Both might be harmful effects, yet of different magnitude. One might be beneficial and the other null, and so on. Add to that complexity time-varying effects, as noted earlier, and you can see how complicated causal reality might be.
Coincidentally, I encountered a relevant study at about the same time that I read the Brownstone article. That study provides insight into the two mechanisms by which Covid vaccines might reduce the risk of death, although the authors missed one aspect of their data (regarding reduced infections) and stopped short of the computation for the other (reduced mortality, if infected).
That’s not surprising. At times of biased media and biased science, we sometimes find insight from narrative-matched publications that missed interesting inference from the data.
Published as a ‘research letter‘, the study compared Covid mortality with mortality from seasonal flu. Using databases of the U.S. Department of Veterans Affairs (VA), the researchers identified patients who were hospitalised with an admission diagnosis of Covid or influenza and ascertained deaths. Most patients were elderly, the age group where Covid mortality is concentrated and effective vaccines are needed.
Did Covid vaccines reduce infections? Although the design was a classical retrospective cohort, the baseline data in the first table may be viewed as data from a hospital-based case-control study. (I cannot get into a technical explanation of ‘propensity score weighting’, but it can be ignored for a basic case-control analysis.)
We may consider Covid patients as cases (numbering 8,996) and seasonal influenza patients as controls (there are 2,403). In a typical hospital-based case-control study, controls are selected from multiple disease categories, but I don’t see a major problem with this control group, and perhaps there are referral-related advantages.
Many complicated issues arise from a case-control study. Nonetheless, the basic analysis is simple. We visually compare the distribution of the suspected causal variable (Covid vaccination status) in cases and controls and compute odds ratios. If the vaccines meaningfully reduced the risk of infection, we should get odds ratios much smaller than 1.
We have no such evidence in these data. The odds ratios are close to 1 (close to zero vaccine effectiveness) and they line up in the ‘wrong’ (unexpected) order of magnitude: the larger the number of doses, the weaker the apparent effect. The causal chain from vaccination to reduced mortality through reduced Covid infections is not corroborated.
Interestingly, we may also view influenza patients as cases and Covid patients as controls and compare the distribution of flu vaccination status in the two groups. Check their table above. There is no meaningful association either.
Might biases account for near-null associations? Biasing paths typically lead to a statistical association when there is no real cause-and-effect relation. Random error aside, it is unusual for biases to turn strong effects into near-null associations.
Did Covid vaccines reduce mortality, if infected? We turn next to the second mechanism by which a Covid vaccine might reduce mortality: reducing the risk of death, if infected. That part was addressed in the original design. Every member of the cohort was infected, either by SARS-Cov-2 or by influenza.
The authors have focused on a comparison of Covid mortality with flu mortality, but they added a secondary conclusion:
The increased risk of death was greater among unvaccinated individuals compared with those vaccinated or boosted — findings that highlight the importance of vaccination in reducing risk of COVID-19 death.
How important is vaccination? What was the vaccine effectiveness — if infected? They don’t say.
If Covid vaccines no longer reduce the risk of infection, that’s the only source of vaccine effectiveness (VE) against death.
Below you will find their table and my computation:
VE of 30% or 40% in the vulnerable population is far from ‘highly effective’, a perpetuated claim. The incremental benefit of booster vaccine (one or more doses, per supplementary material) was even smaller (risk ratio 0.83, VE 17%).
Moreover, 30% to 40% is not necessarily the true effectiveness. We have clear evidence of ‘healthy vaccinee bias‘, a type of confounding bias, in both the U.S. and the U.K.. People of the same age who were vaccinated against Covid were healthier, on average, than their unvaccinated counterparts, as evident by lower non-Covid mortality. Therefore, the unbiased VE should be smaller. For example, a modest bias correction factor around 1.5 would drive VE of 40% close to zero.
Billions have been vaccinated under the slogan ”safe and effective’.
It was neither.
Dr. Eyal Shahar is Professor Emeritus of Public Health at the University of Arizona. This article first appeared on Medium.
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I distinctly remember Chris Whitty telling us back in March 2020 that for most people (80% was the figure he mentioned ISTR), infection with SARS-COV-2 would result in a mild illness, with few or no symptoms.
(Of course that was before he was dragged off to an empty East London warehouse and given the Ipcress File treatment)
So omicron is EVEN MILDER than that?
Inventor of mRNA vaccine platform: omicron is a Christmas present to us
That was when he was telling the truth, before he was re-educated by a fat man that spent a few days in hospital.
You are correct….
here he is, on the very rare occasion he spoke anything resembling truth:
https://mobile.twitter.com/CharlotteEmmaUK/status/1356679458053361667
so what are the hospitals being overwhelmed with then
Obese nurses off “sick” doing their christmas shopping
and obese pen pushing management
Farage pointing out the reality…
https://www.youtube.com/watch?v=FxRvsrYGbX4
I don’t think they are. It is not unusual for statistical anomalies to make one hospital crowded and for excess patients to go to another nearby which isn’t, especially in Winter. In normal times this provokes no comment. In these times…
What sort of treatment do the hospitals provide? All of the effective treatments are banned.
NHS advice to me when I had a bad case of covid at home was take paracetamol and drink lots of water. No other treatment offered or suggested.
I see they’ve approved some antiviral drugs now (new, novel, expensive ones of course), but by the time they’re available the actual pandemic (as opposed to the pingdemic of symptomless ‘cases’) will be over.
I give better advice than that! Lemsip, steam inhalation (maybe just over a coffee mug/aforementioned lemsip), pine needle tea, ivermectin (if you can get it), colloidal silver, prayer, prop yourself up in bed, don’t let what you cough up be recycled, and breathe in to 3/4 lung capacity, hold for three seconds, and breathe out slowly; this will get you to cough stuff up from the lungs (or get something called ‘air physio’). Have a fitbit or similar and watch bp, oxygen saturation, and temp. Take some exercise, and hot baths. Lots of fluid, preferably hot. Black/ red fruit or apple for the quercetin. Vitamins C, D, and zinc.
Anyone tempted to take Molnupiravir needs to read the results of the clinical trials first. Trialsitenews has posted several with analyses.
NHS Default position and advice. Take a drug that Interferes with your brains ability to control increases and decreases in your temperature. Why not unblock your nose while you’re at it. You might be lucky enough to pick up a new virus while you’re recuperating!
I know, remarkable isn’t it? For two years no one talks of anything but covid, google covid treatment, or go to NHS Direct – nothing. I took lemsip, ivermectin and jack daniels. I might not have needed the ivermectin had my wife not substituted aldi’s lemsip for the real thing.
I would advise against Jack Daniels and recommend Eduadour Single Malt. Let´s not put a strain on the pound.
Stop testing and running off to A&E every time you get a drippy nose ffs.
Take a Lemsip or a hot toddy and hit the pit for a couple of days.
hit the pints till its gone – lots of fluids full of vitamins and makes you feel good
https://www.dailymail.co.uk/health/article-2681639/Mines-pint-Full-vitamins-high-fibre-low-sugar-good-hair-benefits-beer.html
I’m not sure the fat pig dictator will be “breathing a sigh of relief”. If he doesn’t lock down and force-“vaccinate” he’s going to have Gates and Schwab breathing down his neck.
Michael Barrymore’s swimming pool is more dangerous than the Omicron cold bug.
Thanks to the unique way in which it’s funded our ONS no longer seems able to provide stats broken down by vax status, but Canada does. take a look at this from Ontario (https://covid-19.ontario.ca/data/case-numbers-and-spread). Raw numbers are even more fun, but to placate the whiners these figures are infections per hundred thou.
The vaxed are catching omicron at DOUBLE the rate of unvaxxed. That turd Welby should take a look at this.
Del Bigtree interviews British Mathematician & Professor of Risk Management, Norman Fenton who reveals ONS data is nonsense.
https://www.bitchute.com/video/tZtwiepFX8fL/
Correct me if I am wrong, but I think you have derived the rate for the vaxxed by adding the rates for partial vaxxed to the rates for fully vaxxed. This calculation is only legitimate if the size of the partially vaxxed population is roughly the same size as the size of the fully vaxxed population. In Ontario that is far from the case: 80% of eligible population are fully vaccinated, 5% partially vaccinated. I attach a chart with the rates for fully vaxxed and partially vaxxed separated out. You will see that they are both below the unvaxxed rate – although all three are very close in the last few days. This is in line with the widely accepted assessment that two vaccinations gives little protection against infection by omicron, although it would be interesting to see the same figures stratified by age.
On second thoughts you can’t add two rates together to get a combined rate whatever the relative sizes of the populations! You can average them if they are roughly the same size.
You’re right, I did, I see that error now. Thanks. So in fact, as near as can be judged, the vaccines are simply making no difference….
Agreed. we already knew that a double dose is not very effective against Omicron.
However, before drawing conclusions, we should stratify for age (and other confounding factors). For example, young people are less likely to be vaccinated and also less likely, other things being equal, to get symptomatic infection.
So the NHS now can’t cope with a bad case of the cold against which millions have been forced to take 3 vaccines? I know so many people who have had surgeries cancelled over this charade. Time for a public enquiry to find out what these idle twats are actually doing all day. It’s certainly not treating the sick.
Bearing in mind that evidence has no impact on the PM as the whole thing is political, showing him virus data is pointless, you might as well turn up with a snowglobe. What frightens Boris is if the sheeple are starting to learn. I’m not talking about the possibilities of ovine aviation, but rather that they stop wearing pointless masks, give up on endless jabs of something or other and realise, hang on, this has never been worse than flu. No, the cheese and wine d*ckhead class are only afraid of polls. Of course, if the MSM did it’s job for just one day…….
The MSM is doing its job. It just isn’t the job they tell us it is.
Looks like the Telegraph is preparing the ground (or “rolling the pitch”, as the politicians like to say) for a reverse ferret by the PM about more restrictions.
Something positive for your day: https://youtu.be/0xQ_OTilgEM
“What we’ve said is up to Christmas we’re fine looking at the data, looking at the numbers we have at the moment, but, of course, we have to look at where this virus goes, where this variant goes, so we have to look at that data.”
What they are looking for is not where the virus or the variant goes, they are looking for ways to distort the true data to support the narrative, because they know that if they carry on the previous basis it will fall apart.
Anyone paying attention to SA and Denmark knew this would be the case. Anyone monitoring the 95% antibody levels knew this. Anyone understanding that far more important than antibodies (which O can avoid to some extent) is T and B cell response which are not impacted by Omicron knew this.
as Professor Gupta said on Planet Normal,
vaccination and prior immunity doesn’t stop people having the virus enter their system. It’s not a Star Trek force field. But it means that once inside the system, it gets swiftly kicked out unless too much drift has occurred (usually over years) or immune system has decayed or is compromised. There is only ever a small percentage (between 5-20%) who might be at risk of illness (not the same as a positive test). Omicron is behaving exactly as expected by anyone without a vested interest in this chaos. So infections will soon peak if they haven’t already as available population to be infected and transmit dries up, illness will soon peak and then crash, and best of all the more dangerous Delta is starved of kindling and likely will disappear. You prefer having no viruses but of all the options available, Omicron is likely the best possible.
Now, it is time for those 14 deaths to be given details: age, prior infection/vaccination, underlying health, and whether they contracted Omicron in hospital or not. Global health leaders need that, since we are claiming the largest Omicron death count. Wonder how fast we get that information?
If they aren’t releasing it, we know why!
If it showed that all the deaths were 20-year-old marathon runners with no comorbidities they would be shouting it from the rooftops!
“… we prefer having no viruses… “
We would all prefer having no viruses but that is where I feel we have gone wrong on this issue. We don’t and never will live in a world without viruses or other pathogens – bacteria, fungus, poisonous plants, insects, bitty animals. My feeling is, not meaning you DrC, that people have forgotten this, or indeed never knew it.
So they fall back on ‘big numbers’ argument. But its not applicable. this virus overwhelmingly creates serious illness in elderly with commaorbidities, there is a limited group under threat. A mild variant will cause few problems to the rest however many ‘get it’. Which of course some of them are now inventing the notion that this mild variant might magically be dangerous to the young without a scrap of evidence.
They’re back to using an idea they haven’t used since early in the first lockdown: No one will ever become resistent enough to Sars-CoV2 that he won’t get seriously ill sooner or later, ie, like untreated HIV, it’ll eventually kill everyone, just much quicker. And the only recourse is keep vaccinating people as fast as you can plus eternal lockdown, with a lockdown summer holiday possibly being thrown in, if the people deserve one.
The underlying problem is here that the invisible Xi in the room must still either admit that his strategy cannot work or it must be repeat-implemented everywhere else forever.
End of November, Savage Jabber was promising that the renewed mask mandate would be abolished again if omicron turned out to be no worse than delta. Assuming the data above is correct, it isn’t (to absolutely no one’s surprise). That’s why they’ve made up the But it’s so much more transmissible that it might still overwhelm the NHS! bit they’ve been repeating ever since.
They test for the flu since they’ve never isolated Covid-19. Which makes me wonder how they can tell there is a delta variant. They never isolated the virus but they use a test to show the damage of a solution does on monkey kidney cells then show the cellular debris as proof of the virus. So, they can use this method to claim an UNENDING! amount of variants. A lot of cancers and “viruses” are probably just different forms of parasites. Since the tests can’t differentiate between cold and flu and covid then doesn’t that mean ivermectin cures both the cold and the flu? Welcome to “they’ve been lying to us our entire lives about everything”. Get your Ivermectin while you still can! https://ivmpharmacy.com
Is anybody apart from me actually reading the Daily Update? Yesterday the reported number of positive tests for Scotland was 2500, down from 6800 the previous day and one of the lowest figures since the start of the Delta wave. Now this may be an error, but surely someone in authority should comment (or were they all too busy cancelling Hogmanay).