AstraZeneca approval in the US

AstraZeneca would be the 4th vaccine in the US if approved.

There are now reports of possible blood clot issues in countries using it and some are putting it on pause.

Do you think this will affect approval in the US and does it affect how you feel about it?

I hadn’t heard about it, so I looked it up. Here is a defense in the BBC:

They allege that the numbers are so low that it’s unlikely that they could be caused by the vaccine, but are just likely natural occurrences that would otherwise not have been noticed. They also cite the WHO as saying it’s okay. And, of course, Britain’s own health organization says they’re fine and for Brits not to avoid their vaccine based on this news.

Personally, since we’ve got the others, I’d be okay with a bit of a delay to make sure things are okay. The rush has died down somewhat. I suspect that the above claim is correct, but it doesn’t hurt to be sure, and the last thing we need is for there to be any reason someone might think the vaccines are unsafe. Even just one being unsafe could get misconstrued by anti-vaxers or even those just nervous about the whole thing.

The AZ vaccine is a non-starter for me. There are apparently issues with it for seniors (that would be me) and I’m on blood thinner medication due to cardiac stents, so anything even remotely suggestive of blood clotting would be a very bad idea. Here in Canada AZ is not being administered to anyone over 65. I understand that in Ireland it’s been discontinued entirely.

I have my preferences for a vaccine (Pfizer or Moderna) and my personal second choice based on no particular hard evidence is Johnson & Johnson, but AstraZeneca is totally off the list.

ETA: The irony of the blood-clotting thing is that AstraZeneca is the maker of one of the most recent and potent anti-platelet drugs, Brilinta.

It is far more likely that people are jumping at shadows with this and that it is just a manifestation of our human pattern-seeking behaviour. Classic “post-hoc” rationalisation.

In any given period you are likely to see many clotting issues occur that are completely unconnected to any vaccine. Some figures are given here.. i.e. for a given cohort of 5 million people getting a vaccine we would expect 100 clotting issues per week even when we know for certain that the vaccine had no causal effect. At the moment we are talking about multiple times more than that being vaccinated and only 30 or cases being raised as an issue.
And remember those numbers are conservative in that the cohorts currently receiving the jab are likely those that would naturally see even higher rates of clotting events.

So in conclusion, it would not be a rational response to think this vaccine is unsafe on the basis of the reports seen so far. The numbers don’t support it and the very carefully controlled massive clinical studies showed no signs of it at any level worth worrying about.

Anyone offered the jab and who refuses it on the basis of these reports is likely putting themselves at greater overall risk by delaying getting protection.

The vaccine doctor guy, Paul Offit, MD, in one of his many books about vaccines (they are all very good reads), tells a story of a man in the UK who took his infant son to be vaccinated, stood in line for a while, but decided he couldn’t wait any longer, and went home without the shot (IIRC, DTaP). The baby died of SIDS that night.

Offit comments that had the man stayed in line and gotten the shot, there is no way you ever could have convinced the man that the vaccine did not kill his son.

There’s also a couple on a crusade against the hep B vaccine for infants, because they lost a newborn who was give the vaccine. Nevermind the infant was in special care, and recovering from a reaction to an antibiotic, when he was accidentally given another antibiotic in the same class. The antibiotic was closer in time to the death than the hep B vaccine, but the parents were already vaccine skeptics who felt they had been pressured into allowing the vaccine.

As much as I hate it, I think in the long run, more people will get vaccinated, if the AZ vaccine is approached with caution. It will probably be allowed eventually, but maybe at first not given to people with previous clotting events, or other reasons to think clotting could be a problem.

There are anti-vaxxers who are not going to get vaccinated no matter what, but they are the minority. There are lots of people who are concerned or hesitant, who will feel better if their concerns are taken seriously. Some kind of trial specifically to look at the issue may put a lot of people at ease.

It may, or may not. Seeing as no matter what vaccine you give and no matter how carefully you scrutinise it, there will be medical events that happen immediately after the jab.

Quite why this particular issue has gained the publicity it has is unclear to me. There is a process in place to monitor such adverse events and nothing significant has been seen in either the massive clinical trial or the close monitoring of the multi-millions of people vaccinated so far. Particularly in the UK. The approach to vaccinations, monitoring of adverse events and joined-up thinking from the NHS is pretty much gold-standard. Were there something there to be concerned about I’d expect that signal to be spotted pretty quickly.

As it stands neither the WHO, the MHRA or the EMA think there is a problem. The countries deciding to halt use may well be using an over-abundance of caution and the back-of-a-fag-packet calculation can be done fairly simply.

Certainly if a country like the Netherlands halts AZ vaccinations for two weeks that is likely to leave 250,000 people unprotected (Assuming they can’t just step up other vaccinations).
Over those 2 weeks, with a case rate of 200 per 100,000 you can soon see that you are certain to have hundreds of people catching it that didn’t need to and a known proportion of those will definitely die, certainly more than we know have died as a result of reported adverse events. (especially given that those missing out on those vaccines are in higher risk categories at the moment)

And that’s just the Netherlands.

So that’s the sort of risk/benefit calculation that needs to be done in these situation. And it needs to be a sober and data driven assessment and to the best of my knowledge it is. The process is working and I’m not convinced those countries who have paused the roll-out have any statistical basis on which to do so.

They may well be making a rod for their own back when other non-connected adverse events come to light (which they certainly will).

I realize this.

However, pausing briefly and then resuming, with many people’s minds at ease, and the refusers being people who would refuse no matter what, may ultimately lead to more being vaccinated than not halting, and causing a lot of people to dig in their heels, until a campaign against AZ mushrooms, and the vaccine is discontinued altogether, or at least, reformulated and rebranded so that it receives public acceptance.

I disagree. The pause should be based on proper analysis and not anecdote with the case for action to be made on that basis. A constant pausing and resuming based on anecdote alone is, in itself, undermining of public confidence.

AstraZeneca are reporting, after 17m doses have been given in the UK & EU, that the incidence of blood clotting is actually lower than is normally expected in the general population. This sounds like a story which has gotten out of control due to isolated anecdotal reports.

I sometimes wonder if some countries are pointing fingers at AZ to distract from their woefully inadequate vaccination programmes.

At this point that is certainly what it looks like. And this was always going to happen because the public generally are terrible at making an assessment of such risks and occurrences. We are pattern-seeking mammals.

My earlier post on this based on things I’d heard appears to have been overly alarmist. This is what the media likes to call “a developing story”, and quite likely not a story at all. The latest information appears to be:

No credible evidence of blood clotting, and the European investigation is focusing on specific batches of the vaccine. The countries that have stopped using it have done so out of an abundance of caution:

And, the hesitancy to use it in seniors was not based on any known risks, but on lack of adequate evidence of its efficacy. Health Canada guidance in this regard has been called “outdated” and is expected to be revised.

…and this, incidentally, was a result of the study design. For reasons I wouldn’t even speculate at, the pooled efficacy analysis groups in the studies used for authorization of the AstraZeneca vaccine had very small numbers of seniors:

Age at screening >= 65
Active: 686
Placebo: 665

By way of comparison, if I remember correctly, the main Pfizer study had a total of 17 000 subjects in this age group. The upshot was that the sample size was too small for AZ to draw meaningful conclusions on efficacy for age 65 and up. The EMA decision to authorize its use in age 65+ was based on immunogenic response in that group, rather than proven clinical efficacy.

There is currently a paper in pre-publication which addresses this issue.

To estimate the real-world effectiveness of the Pfizer/BioNTech BNT162b2 vaccine and Astrazeneca ChAdOx1 vaccine against Confirmed COVID-19, hospitalisations and deaths. To estimate effectiveness on the UK variant of concern…

Individuals aged >=70 years vaccinated from 4th January had a similar underlying risk of COVID-19 to unvaccinated individuals. With BNT162b2, vaccine effectiveness reached 61% (95%CI 51-69%) from 28-34 days after vaccination then plateaued. With the ChAdOx1 vaccine, vaccine effects were seen from 14-20 days after vaccination reaching an effectiveness of 60% (95%CI 41-73%) from 28-34 days and further increasing to 73% (95%CI 27-90%) from day 35 onwards.


Yeah, I noted in some earlier topic that the FDA expert panel was not unanimous on the Pfizer approval, unlike Moderna, for basically the same reason. Pfizer sought approval for 16+ despite very few <18 yr olds in the trials. Nobody even noticed that but this story is making headlines.

Exactly. My parents are what I would call “soft” anti-vaxxers. They’ll probably get the vaccine eventually, but not until they have to (like to travel abroad). I don’t try to convince them, as there’s no point. My father is constantly, well these people developed these side effects, or did you hear about these people who died, etc., and I keep telling him that telling me that you pick a million people, a few of them are going to die in the next day or two, or come down with an illness, or have a embolism, or something, vaccine or no vaccine. It simply will happen. Without having data of what is normally expected to happen in a population along a certain timeframe, you can’t just blame the vaccine, as a certain amount of these outcomes would have happened anyway.

Maybe you could use that against him. “Hey dad, you know that guy who died of a heart attack the other day? He wasn’t vaccinated. 'Nuff said”

I wish reverse logic were so easy. I used to also get the “but person X got the flu vaccine and they got the flu the next day (or two days later)!” in years before, which is problematic on multiple levels. (One, unless you’re getting the nasal one, it’s not a live virus, so you simply can’t (as far as I know); two, it’s not a perfect vaccine; three, it’s not effective after a day or two; four, are you sure it’s the flu and not an immune response to the vaccine; etc.) Meanwhile, he’s telling me about African countries rejecting the COVID vaccine because 1.5 million people were sterilzed by it, or something like that, and I have no fucking clue what he’s talking about. I remember the tetanus vaccine rumor. Where does he get this from? He doesn’t even have the internet. And then he’s like, well this well-studied doctor said this, and I have to say “you can always find a few doctors to say whatever you want. What does the consensus of the medical community say?” And then it turns to: “Well these people say this, and these people say that…how am I supposed to know who to believe.” “If they’re shouting at you on AM radio, those are things you probably should be skeptical of.”

I just give up. Now, I do approach all this in a calm matter these days and try to change the topic, but it’s exasperating internally.

It’s incorrect to call it the AstraZeneca vaccine: Oxford University created the vaccine so it’s reasonable to use both names when referring to it.

Interesting. So, it’s possible that there is more to it on a small scale, and not much to it on a larger scale. If they are looking at specific batches, then perhaps the small numbers are meaningful, if they are associated with specific batches of vaccine. But, if that’s the case, then, assuming the issue is not widespread, the vaccine in general is likely safe.

But I would, assuming all that is true, want to know that they’ve figured out what happened to the batches they are investigating, and that the problem has been solved.

I tend to give public health officials that have way more information than I do the benefit of the doubt. If there are suspicions of bad batches of vaccine causing problems, but no identification of the cause, then I could understand pausing the vaccine while the issue is identified and it is established to not be an issue anymore.

I assume it’s just too long of a name for colloquial use. I hear it called “the UK vaccine,” “the Oxford vaccine,” and the “AztraZeneca vaccine.” Similarly, the “Pfizer vaccine” is fully the “Pfizer-BioNTech” vaccine. Is there something wrong with not using the full name?

If you don’t want to use the full name call it the Oxford vaccine. Without Oxford there would be no vaccine; without AstraZeneca it would simply have been another of the drug manufacturers who did the large scale trials and manufactured the vaccine [originally it was going to be Merck–but the UK government was worried that Trump would put distribution restrictions on the vaccine if Merck was the manufacturer].