I'm puzzled about something related to the AstraZeneca vaccine. Several European countries have put it on hold due to reports of blood clots in patients who have received it. If I have the numbers right, about 40 cases of blood clots have been reported out of the 17 million people who have gotten the AZ vaccine.
But COVID-19 itself is far more dangerous on the blood clot front. "Blood clots continue to wreak havoc for patients with severe COVID-19 infection," reported the University of Michigan Health Lab a few months ago, and that hasn't changed.
So let's do some arithmetic. The overall hospitalization rate for COVID-19 is about 100 per million per week, which means that of the 17 million who have received the AZ vaccine since January, something on the order of 17,000 would have been hospitalized if they hadn't been vaccinated. The incidence of blood clots in patients hospitalized for COVID-19, according to a recent study, is about 20%. This means that roughly 3,000 people out of those 17 million would have developed blood clots without the vaccine, simply because they would gotten a serious case of COVID-19.
So . . . 3,000 without the vaccine, 40 with the vaccine.¹ That seems like a no-brainer: keep inoculating people with the AZ vaccine until firm evidence of large-scale harm emerges.²
Unless, of course, I bollixed up my amateur risk-assessment arithmetic. If I did, what am I missing?
¹Also, AstraZeneca claims that 40 cases out of 17 million is about the same as it is for other vaccines. I can't verify that at the moment, but I wouldn't be surprised if it's true.
²The calculus might work out differently if you had plenty of alternate vaccine supplies, but I don't get the impression that's the case in Europe.
17 * 100 = 1,700
👍
x 10 (weeks over which the AZ vaccine was administered)
You are right, Ken. I didn't see that. Thanks.
Jim
Kevin, you're right (at least, based on the data we have). I think some part of the reasoning is "well, it's not a choice between AZ and nothing: there's a third choice, which is another vaccine". But that third choice isn't real until actual supplies of that other vaccine show up.
So maybe a different calculation would be to project how many people will have to wait, and for how long, for a different vaccine, and how many of them will fall ill with covid, enough to be hospitalized, etc. I'm sure that calculation also will show that it's a bad idea to wait.
I think the comparison is not "use AstraZeneca" vs. "do nothing". It's "use AstraZeneca" vs. "wait a few more months to get some other vaccine". A few more months does not produce huge exposure risk to covid. Risk, of course. I don't have the numbers in front of me, but that's the comparison to make.
AND, the general public is risk averse. They don't think statistically. They will go "THAT one gives you BLOOD CLOTS!!!!" Umm, or really, they weight negative outcomes about 3x as much as a statistician would. This is close to universal. It must be accomodated.
Given that Covid-19 generates blood clots, and case severity varies a lot, I wonder if the statistics include people who already had blood clots when they received the vaccine.
Sounds like a excuse not to vaccinate. 100 million dollar doses sitting for nothing. It's a scam reason not to vaccinate, pure and simple. Many prefer lockdown and awaiting until warmer weather arrives.
Mind-reading again Shootie? Pro tip: being drunk does _not_ mean you've developed a sixth sense. Quite the contrary.
Self hatred is bad. You literally hated your own being
😉👍
^^^AND, the general public is risk averse. They don't think statistically. ^^^
Yes, but surely that's what governments (and the scientists on their payroll) are for.
But that is missing the point that Kevin is making. He is comparing two risks. If you were really risk averse you should be getting vaccinated as quickly as possible.
i think the idea is the general public is "risk averse" in a non-optimized, non-statistically valid sense. they default to non-action when they feel that action might have some risk, even if the risk is infinitesimal but scary sounds like "vaccine causes blood clots", and the risk associated with inaction (not getting vaccinated) are actually higher.
I haven't seen reporting of any clear data indicating that the AstraZeneca vaccine has caused anyone to have blood clots. Lots of people got the vaccine, and a tiny fraction of them suffered from blood clots afterwards. Coincidence? I think so!
It's stupid to worry about it given the full data.
A panic over getting ahead of popular panic, or some other issue they don't want to talk about?
I’ve also seen reports of an attitude in some places in Europe that the single-shot adenovirus-based vaccines are “second class” compared to the mRNA vaccines.
They are slightly less effective, so for the most at risk (who are the first being vaccinated) that are a poorer choice. The single-shot vaccine makes more sense for younger, healthier people.
Pingback: Is the AstraZeneca Vaccine Really Dangerous? | Later On
For some reason the article Kevin linked to wouldn’t come right out and say it, but I think it is saying that Covid causes the body to produce more than one kind of antibody and some of those types can increase the chances of blood clots. So I think this indicates that the vaccines produce more than one type of antibody also. I think they are trying to say that if you could make a vaccine that only produced the non-harmful antibodies, that would be ideal.
I’m also not sure why Kevin said "about 40". A different article I read said the number was 37. Just say 37. Or about 2.2 per million. Neither article bothered to say what the number per million is normally - 1 per million? .1? More? Less? Last I checked it wasn’t that rare for people, especially old people, to get blood clots.
Depends on who is getting the clots--not just the number.
If healthy individuals develop blood clots for no reason, that would be bad. If people who are more at risk develop them, than that could be normal.
If those getting blood clots have a very low chance of serious disease with Covid, then waiting for different vaccine makes individual sense, though not public health sense.
If the blood clot issue cannot be readily treated and is long term, then that would be bad. Though no evidence for that.
Your right, the overall number is vanishingly small. Apparently that rate of blood clots is lower than what would normally be expected. Not sure why this is in the news--or countries would consider suspending vaccinations with this vaccine.
Weak correlation is cause for panic, obviously. Full stop.
/S
I read a story today on Sky News which stated that the MHRA has said that the rate of clot formation is indistinguishable from the background rate. If that is the case, there is really no reason to slow this train down.
Estimating a rate of ~2/million with a reasonable confidence interval or probable error takes a huge volume of data; same for finding a statistically-significant difference between two very small rates.
Except that we have a huge volume of data. Even if the 2/million just represented 2 cases out of 1,000,000 opportunities, the 95% confidence interval (binomial exact) around that estimate is 0.24 per million to 7.22 per million. The upper end of that interval is not an alarming figure at all.
And if Kevin Drum is right that 17 million Astra Zeneca doses have been administered, it's 1.4 per million to 2.8 per million. It is hard to imagine any decision making that would require greater precision than that.
What I'd worry about more than sample size issues is the quality of the data. Diagnosing blood clots is a difficult process. Many people given the diagnosis don't have them, and many people who have them don't get the diagnosis. My concern would be with the accuracy of that numerator: how sure are we they really had blood clots, and how many others might we have missed.
Thalidomide, and who wants to be officially associated with that sort of approval?
The Other T-Zone.
The Guardian reports that the blood clots are in the brain, that there are other blood related issues including hemorrhaging and low platelet counts, and that people have dies as a result of the clots.
https://www.theguardian.com/world/2021/mar/15/germany-suspends-oxford-vaccine-over-blood-clot-fears
It also reports there have been no links to the vaccine other than those that died had been administered it. Oddly left out of the report were the past medical histories of the departed, and the other people that died from clots and hemorrhaging while not having been administered the vaccine.
Exactly. There is a base rate; the correct question is whether the observed rate exceeds it significantly.
Two of my grandparents died from cerebral thrombosis, but it was last century. That makes me VERY suspicious that this vaccine has been used by governments for many years, without us knowing!
The AZ makes up only about 20% of the EU supply. Also the vaccine is only being put on hold until the EMA rules on this (probably on Thursday)
So really the choice is
1) Delay 20% of vaccinations for about a week to demonstrate that they take safety issues seriously
2) Ignore the issue and hope no one notices.
Either way you give ammunition to the anti vaxers so I’m not which is worse.
Reporting from in inside Germany, I think this is the right take. I personally have a hunch that Russian media influence is also playing a role, as the Sputnik V vaccine is now being pushed hard. Hungary already waived testing and approval, and other former Warsaw Pact EU countries are being courted.
Putin has never been a friend of the EU, and I think it is all too plausible that he would use disinformation about Astra Zeneca to sow discord. AZ is already suffering from news stories about how delivery is less than initially promised, with speculation that it went to the highest bidder and that the reports of problems getting production up to speed are a smokescreen.
Logic and saving lives has nothing to do with it. The EU currently has a lot of egg on its face when it comes to vaccinations. Loudly proclaiming "we're not sure that the vaccine is safe!!!" is in their best interest.
Look-- the last four years have involved a lot of (mostly justified) snickering about the sheer incompetence of the Trump administration and Brexiteers. The EU felt good about itself.
And now these incompetents have been able to handle vaccinations at the rate that puts the EU to shame. The public is not impressed.
Muddying the waters and proclaiming that the delays are due-- at least in part- to the need to protect public safety makes them more palatable.
Never mind the excess deaths in the meantime.
What you are missing, Kevin, is two things. First the EU and its member countries have proved hopelessly incompetent on vaccinations. This is just another stupidity on their part. Particularly countries like France that really, really need tourism to return this summer should be accelerating vaccinations instead of slowing them down. Second, the people Up There want to prove to us Down There how serious they are about vaccine safety. Except they're proving the opposite when they give in to unfounded scares. This will not diminish vaccine hesitancy but increase it.
Kevin’s numbers on the Astra Zeneca vaccine combine the vaccines produced in the UK for the UK market, and those produced in a new plant in Belgium for the EU market.
Something like 11 million doses of the Astra Zeneca vaccine were administered in the UK without unusual problems. The number of problems reported in EU countries already exceeds that, even though only about 5 million doses have been administered, and includes two unusual deaths. These problems are showing up in young people, who aren’t usually at high risk for clotting problems. Norway has reported a couple of “unusual” clotting problems, suggesting these aren’t just normal course health issues.
Astra Zeneca has been reporting other problems with its Belgium plant, which seems to be having lower yields than its other facilities. Vaccine production is not an exact science, and the Belgian plant is a new facility which hasn’t done a lot of vaccine manufacturing before.
This may turn out to be a “bad batch” problem instead of a “bad vaccine” problem. Or it may turn out to be unrelated. But a bit of caution is warranted here.
EU’s vaccine rollout is a massive FUBAR. As The NY Times is reporting today, they tried to save a few bucks on the vaccine (paying $15 a dose to the US $20 and Israel’s $25). As a result, they got moved to the back of the line, and the cost of new lockdowns has pretty much eliminated any cost savings. But that money is already lost.
THE EU did pay less for the Pfizer/BioNTech vaccine but that is not a factor in the supply problems Pfizer has delivered the promised number of doses. The shortfall is almost entirely in AZ vaccines.
Also keep in mind that the EU does not ban the export of vaccines as the US and essentially the UK do. In fact the EU is major exporter. Half of the UK vaccines are imported from the EU. All of Israel’s are. And according to the WSJ, 20 millions Pfizer vaccines were shipped to the US in December after delays in the Kalamazoo factory.
The EU could have made up the AZ softball by banning the export of Pfizer vaccines (I’m glad they didn’t) but you can imagine what the narrative would be then
“Greedy EU won’t export vaccines”
Except right this moment EU are blocking the export to Australia of doses they aren't even using.
You are correct they blocked one shipment of AZ vaccines. But the US is also sitting tens of milliosn of AZ vaccines (according to the NY Times) which are not even approved for use in US. And the UK is not exporting any either.
So my main point is still valid.
Well! Everybody knows it's sad if a wild virus strikes you and you die, but to have a vaccine maker make you unwell, is well, terrible. I just heard last night that someone was afraid of taking the Moderna vaccine because of COVID arm, which ain't even half as bad as poison ivy, or anaphylaxis which is serious but not their reason for fearing the jab.
Yeah but the anaphylaxis is not that big a threat. You wait around 30 minutes to make sure it won't happen or if it does you fall over and start dying but then the nurse runs over and stabs you with an epipen and you're fine. Bloodclots ARE A SILENT KILLER. Amirite!?
From my reading (Kai Kupferschmidt) onee concern was the type and severity of the clots with the vaccine.
Apparently the rate of blood clots with the other vaccines is not different. But this does not seem to be emphasized, maybe because that would make people aware that they occur with all vaccines, never mind that the rate is not higher than among the non-vaccinated population. Any little thing can trigger an irrational public reaction.
That's actually a lot more blooclots than when I checked the issue yesterday (13 to 40). Also I understand it's got some sort of anti-clotting built in.
I would assume EU is waiting until the large scale US trial is done since that should provide more and better data than existing trials.
This doesn't take into account your actual risk of catching covid during the time they are evaluating the stroke risks of the vaccine. We all know that risk of infection is not even across all people. Some of us rarely leave home, while others work in emergency rooms or hang out at bars.
For people with a lot of exposure, a slight risk of stroke from the vaccine is probably worth it. But for people who are able to remain distanced (work from home, living in a home with few others, masking on the rare occasions you are outside your home), I'm not sure it's worth it yet.
Welcome to the trolley problem.
People seem to consider it vastly more important when people die as a result of human agency than when they die as a result of nature.
cf -- pretty much every medical product liability lawsuit ever.
Is this rational? Is it something politicians should respect? Should I have to suffer when other idiots feel this way but I don't?
I report, you decide.
AZ has delivered about 10% of what was promised so far in the EU, so the limiting factor in most countries' vaccine programs has been the availability. The massive vaccination programs will hopefully start in 1 or2 months, when there will be more vaccines available (depending on things like 'will the J&J vaccine that is produced here but bottled in the States be allowed to leave the US since the US has an export ban').
That means postponing vaccines at this stage will just mean a small percentage of the population will get vaccinated a bit (1 week? 2 weeks?) later, only the ones that were planned in for the AZ vaccine. It will not be hard to add the smaller numbers that are paused now to the bigger programs.
Europe is on average much more vaccine sceptic than the US (or the UK). So it is much more important that vaccines are trusted. If the Netherlands get 70% vaccinated but France only 50% there is still a big change that the virus will roam and mutate... So institutions here have to be very careful, show that anything weird is immediately researched to minimize risks. Vaccination is a question of trust, every person vaccinated must be sure that all the facts about the vaccine are being conveyed transparently and thoroughly.
Norway and Denmark reported rare thrombosis cases. The Germans looked at the thromboses figures and said that it was normal, but they looked more carefully at the reported cases. The German Paul Ehrlich institute found three extra reports of a rare cerebral blood-clotting disorder, CVST, since Friday, making a total of six or seven (the seventh diagnosis is apparently a little ambiguous). Three of the patients have died.
The German govt's vaccine experts believe that over the 14 days after inoculation you would statistically expect to see 1 to 1.4 cases of CVST per 1m people. Among AZ vaccine recipients the incidence is about 4 per 1m - so three or four times the expected rate and they include younger people - especially women. Now 4 times a tiny chance is still a small chance, which is why a lot of recommendations say that not vaccinating is worse than the risk.
But the German health minister says that it can be sued if it does not, as legally required, inform doctors and patients fully about the possible side effects. Mainly to make sure people trust the info on the vaccines, because they cannot be forced to take it. Other countries pause too, for more or less similar reasons (some European countries don't stop).