Tag Archives: AstraZeneca and blood clots

Real-world information on Covid vaccine effectiveness

Posted on by
48

For the first time, we have some real-world data about how effective the Covid vaccines are. The good news is that a very small percent of fully vaccinated people get sick. The bad news is that the vaccines aren’t  a three-hundred percent effective suit of armor against serious disease. Or even quite one hundred percent.

Among the 77 million fully vaccinated people in the US, the Centers for Disease Control reports 5,800 Covid cases. That’s somewhere in the neighborhood of 0.0001%. Of that group, 7% were hospitalized and 74 died, and damn it I wish they’d give statistics either entirely in percentages or entirely in absolute numbers to dopes like me could compare them. I can get as far as saying that most of the cases have been either mild or asymptomatic. If you can translate, leave me a comment. Even if your answer’s wrong, I’m not likely to know. 

Infections in vaccinated people are called breakthrough infections, and it would be unusual if they didn’t happen. They were found in all age groups, although 40% were in people who were 60 or older, 65% were in women, and 29% were asymptomatic. 

Irrelevant photo: apple blossoms

So far, they haven’t identified what, if any, risk factors incline vaccinated people toward getting Covid or which (if any) variants are more likely to be involved, but believe me, someone’s staying up late crunching numbers. It’s also not clear how the asymptomatic cases were noticed, since it’s unusual to test fully vaccinated people who show no symptoms. It could be that they were hospitalized for other reasons and a Covid test was run as part of the admissions routine. Whatever the reasons, though, we can assume that the number of asymptomatic infections is an underestimate.

But didn’t they tell us that the vaccines were 100% effective against severe Covid? Yup, they did, and they weren’t lying to us. The odds of a fully vaccinated person getting a severe infection are so small that the sample would’ve had to be insanely large for a case to have surfaced. The people who ran the trial gave us the numbers they had. As real-world information comes in, those numbers change. That’s the annoying thing about the real world. Every so often, it doesn’t line up with our predictions.

I get a rightwing newsletter in my inbox every so often–it’s been interesting so I don’t unsubscribe, although I’m not the person they have in mind–and it’s fond of reporting on cases of people catching Covid after being vaccinated. The tone leans heavily toward See? We told you it didn’t work. If I could, I’d compare that 0.0001% of breakthrough infections with the percentage of unvaccinated people who catch Covid in the US, but we’ll need a person with some minimal mathematical competence to work it out. I asked Lord Google but he was in one of his moods. If you’d like percentages on many unrelated things, I can point you in the right direction. 

The conclusion, if you want one to put in your pocket and take it home, is that the vaccines aren’t 110% effective and we still need to be careful, but we can let go of the anxiety. The numbers are on our side here and the anxiety isn’t helping anyway.

There’s nothing like someone telling you not to be anxious to make you less anxious, is there?

The additional conclusion is, keep the mask. Even if you’re vaccinated, you can still spread the disease. You’re less likely to–if you have an asymptomatic case you’re likely to have a lower viral load–but you can still do some damage. Other people share this world with us. Try not to do them any more harm than you can help.

 

What’s the story on vaccines and blood clots?

The two vaccines that have been linked to very rare incidents of blood clots are based on a single technology–one they share with the Russian Sputnik V vaccine. Basically, they take an adenovirus–that’s a virus that causes colds–deactivate it, and turn it into a chariot for the vaccine to ride in on.

Vaccines are hopelessly vain. They can’t resist a grand entrance. Horses, polished metal catching the sun, noise, dust, cameras. 

The clotting problem seems–and we’re still at the stage of seems–to be related to that damn chariot. 

The clots happen in veins in the brain, in the abdomen, and in arteries, and at the same time the person’s level of blood platelets fall, and those platelets are the beasties that help our blood clot. We end up with blood clots happening at the same time as hemorrhages, which in everyday English means bleeding. That’s kind of like an elevator going up and down at the same time. 

Normally, you’d pour an anticoagulant called heparin into a person with a blood clot forming in scary places, but when you pair the clots with hemorrhages, you can’t do that.

What are the signs that a person’s getting a serious reaction to one of the vaccines? Severe headaches, abdominal or leg pain, or shortness of breath within three weeks after vaccination.

Every article about this says the clots are very rare. 

How rare is very rare? Last I checked, 222 cases had been linked to the AstraZeneca vaccine in Europe and Britain, along with 18 deaths. That’s out of 34 million people who’ve gotten the vaccine. Most of those were in women who were–okay, not young but under 60, which looks younger all the time. In the US, the Johnson & Johnson vaccine has been linked to 6 cases out of 6.8 million people who were vaccinated with it.

So how rare are the clotting problems? About the same as the chance of being struck by lighting in the UK in any year you choose. And that’s in a country that, by comparison with the American Midwest, doesn’t get a hell of a lot of lightning.

The risk of Covid, though, is no small thing. 

And if you’re inclined to roll the dice by going unvaccinated, the risk of having a blood clot after a bout of Covid is 8 times higher than after getting the AstraZeneca vaccine. The risk of clots after Covid is 100 times higher than after a normal infection.

 

Covid immunity and prior infections

And vaguely related to that is the news that having had Covid doesn’t give young people full protection from another bout of it. That’s from a study of 3,000 healthy U.S. Marines who were between 18 and 20 years old and unless the regulations have changed since last I looked had radically and irrelevantly short hair.

Even though the marines had antibodies, they didn’t have the level of protection that the vaccine offers: 10% got reinfected. That compares with 50% who hadn’t had an earlier infection, although in the previously infected group 84% of the infections  were asymptomatic or mild compared to 68% in the previously uninfected group.

The numbers of infections and reinfections were higher than would be likely outside of a military base because of the cramped living conditions and close contact.

The advice to people who’ve recovered from Covid is to boost your immunity with a vaccine.

The AstraZeneca vaccine update

Posted on by
21

AstraZeneca’s vaccine is back in the news, and not happily. The company handed a group of US medical experts data on its effectiveness, but when the experts looked at it, they said, “Guys, this isn’t new data. This is the old stuff.”

Except that if they’d really used those words, they’d have said “aren’t new data,” because experts use the word enough to remember that data are plural. All experts. Even experts in knitting and basketball manufacturing. The word data is in a category that includes nonbinary people who prefer to be called they instead of he or she. Those of us who are over the age of a thousand struggle to get the pronouns and the verbs right. 

In case you’re interested, data is made up of lots of itty-bitty little datums.

No, sorry, that’s wrong too. A single datum has to have at least one friend before it become data.

Where were we?

Irrelevant photo: Blackthorn.

Basically, the experts were saying that AZ had cherry-picked its data to make the vaccine look like it was 79% effective. What the experts saw was between 69% and 74% effectiveness.

The craziness of all this is that a vaccine with 69% effectiveness is still damn good, and the advantage of AZ’s vaccine is that it’s easy to transport and store, so it doesn’t have to match the effectiveness of the fussier ones to be useful.

AZ said it had released interim data and that its later data (which rhymes if you pronounce your Rs the English-English way, like silent Hs) was consistent with it. Sorry: with them. It then released the lata data to the experts.

None of this is about the vaccine’s safety, but Dr. H. Cody Meissner, an infectious-disease expert at Tufts University School of Medicine who serves on a board that advises the US Food and Drug Administration on vaccine approvals, said, “You know the anti-vaccine community is going to use this as fodder to argue that pharmaceutical companies are always deceptive.” 

He said board members would be even more careful than usual to scrutinize AZ’s  data from here on, and “I will make sure I don’t skip a word.”

Which is probably not the response AZ was hoping for.

 

Yeah, but what about the AZ vaccine’s safety? 

A number of countries put the AstraZeneca vaccine on hold for fear that it was linked to a very rare blood clotting problem, cerebral venous sinus thrombosis. AZ’s recent US trial involved 21,000 people and turned up no safety concerns, although when a problem’s extremely rare it could easily not show up in a sample of that size. Or of ten times that size.

But even if the vaccine does, very rarely, cause cerebral venous sinus thrombosis, the risk of not using the vaccine is much greater than the risk of using it. Either all or most (or, hell, I’ve lost count; let’s just say many) countries that put it on hold have by now started to use it again. 

 

Magical Covid solutions that may turn out to be real

I try not to write about Covid solutions that are still in the trial stage, because we may never hear of them again, but every so often I can’t stop myself, so let’s talk about protease inhibitors. They’re antiviral treatments in pill form that can be used in the early stages of an infection to keep the virus from multiplying.

What’s a protease inhibitor? It’s a–

Would you mind if I duck that question? We can all live perfectly full lives (and pretend we understand this) without understanding this fully. So a protease inhibitor is a thing–probably one that inhibits proteases–and it’s already been used to treat other viruses, including HIV and hepatitis C. It’s also been used to treat Covid, but up to now it has to be delivered into the blood stream slowly, so its use has been fairly limited.

As someone or other said, “This is really a potential game changer.”

One of the unexpected side effects of the pandemic has been that experts and politicians are required to use the phrase game changer at least once a week. By now, we’ve changed games so often that we don’t know if we’re playing cards or jump rope, or possibly that game involving horses, mallets, and a the head of a dead goat. But as long as we’re changing games, I should mention that they’re exploring the possibility that the treatment could also be used in people who’ve been exposed to Covid but who haven’t yet developed it.

Folks, this really does sound–ack–game changing. Have you got your goat’s head? The price is only going to go up, so if there’s room in your freezer you might want to buy now.

Because Covid’s protease doesn’t mutate much (at the moment, anyway), this would work against all the current variants.

All this made me so happy that I made myself an extra cup of tea this morning. 

Yes, I live close to the edge.

 

The lockdown report

England’s current lockdown rules are scheduled to ease up on March 29. People will be able to get together outdoors in limited but larger groups. People will be allowed to leave home for non-essential reasons. (Hands up: How many of you remembered that we haven’t been allowed to do that? I just thought there wasn’t much non-essential to do.) 

But non-essential shops and services (barbers, hairdressers, that kind of thing) won’t reopen until April 12, along with bars and cafes that have outdoor seating. (No eating or drinking indoors yet.)

Why is April 12 safer than March 29? The virus is afraid of even numbers. It’s all been worked out by people who know what they’re doing. Unfortunately, they had to run their recommendations past Boris Johnson’s government, which threw all the cards in the air and picked them up in random order. Still, some semblance of sanity may still be in there.

Okay, I’ll admit: That was unfair. The idea is to take this thing in stages and only go to the next, more open, stage if Covid stays below some unspecified level. 

The travel industry had been hoping that foreign travel would get the green light, but it hasn’t–or at least overseas vacations haven’t. Or holidays, as you’d say if you’re British. You can’t “leave England to travel to a destination outside the United Kingdom, or travel to, or be present at, an embarkation point for the purpose of travelling from there to a destination outside the United Kingdom” without a reasonable excuse.

Is that clear enough? It means you can’t leave, travel to, be present at, or consider the possibility of thinking about getting ready to go somewhere else. And if that didn’t cover all the possibilities, it’s because I nodded off after one of the ors.

But in spite of all the repetition, there are exceptions, and they’re hidden in that bit about reasonable excuses, which in spite of being outside the quotation marks is a quotation, but one that went wandering and doesn’t belong in that particular spot. 

If you need to travel for work or study, to vote, or for legal obligations, you’re okay. If you need to be present at a birth. If you’re visiting a dying relative or close friend. If you’re getting married. If you have a medical appointment. If you–well, a few other things. 

The reasonable excuse that’s raising eyebrows is that you can travel to get a second home ready to sell or rent. Or you can travel if you just have to buy or rent one. Or to do a few other things with one. Because if you have the money to buy, sell, rent, or hand Christmas lights on a second home, you’re more important than someone who’s hoping to stay in a youth hostel in Spain for a week or two. And if you’re more important, you’ll have the sense not to import some new Covid variant.

That’s being called the Stanley Johnson clause, after the prime minister’s father, who traveled to his villa in Greece to make it, he said, Covid proof. I don’t think he’s told the rest of us how that’s possible. But no, it wasn’t so he could sit in the sun and drink himself senseless. 

Sorry–I suckered myself into a stereotype there. I have no knowledge of what Johnson Sr’s drinking or sunbathing habits are. 

What’s a villa? “1. A country estate. 2. The rural or suburban residence of a wealthy person.” Or in British real estate-speak, “3. A detached or semidetached urban residence with yard and garden space.”

For Stanley Johnson, we can, I think, rule out the real estate-speak definition.

I’m happy to report that protests will be exempt from the rules banning large gatherings, but the organizers will have to work out (or encourage, or some other vaguely related verb) social distancing and mask wearing. That sounds surprisingly reasonable, although it leaves a worrying gap that allows for breaking up spontaneous demonstrations, even if people wear masks and keep their distance. 

More on why countries are pausing the AstraZeneca vaccine

Posted on by
36

The European Medicines Agency has reviewed its data on the AstraZeneca vaccine and reports that it finds no higher risk of blood clots but also says it will keep on studying the possibility that the vaccine has caused them. Thirteen countries in the European Union have suspended their use of the vaccine at a time when vaccine supplies are already short. Or maybe that’s twenty countries. I’ve seen both numbers and don’t much care. Take your choice.

The however-many countries haven’t gone off the deep end, even if at some point it becomes clear that they’ve made the wrong decision. At least thirteen people have developed a rare set of symptoms involving widespread blood clots, low platelet counts, and internal bleeding. These aren’t typical strokes or blood clots, and the people are between twenty and fifty years old and previously healthy. 

Seven of them have died. 

Steinar Madsen, the medical director of the Norwegian Medicines Agency, said, “Our leading hematologist said he had never seen anything quite like it.” 

On the other hand, Britain has had no clusters of unusual bleeding or clotting problems, in spite of having used 10 million doses of the vaccine by now–more than any other country. 

The question of how to read the evidence and what to do in response seems to have divided the public health experts from the medical people. On one side is the argument that Covid is the statistically greater risk, so keep vaccinating. On the other side is the argument that we don’t know what’s going on here and until we do we need to stop. Neither side is either crazy or irresponsible. It’s a question of emphasis and professional orientation. 

*

Update: Four countries have announced that they’ll be resuming AstraZeneca’s use.

*

My thanks to Sabine for sending me a link explaining the reasoning behind halting the use of AstraZeneca. 

Why countries are suspending use of the AstraZeneca vaccine 

Posted on by
36

An assortment of countries have suspended use of the AstraZeneca vaccine out of fear that it might cause blood clots. That includes Norway, Denmark, Ireland, the Netherlands, Cyprus, Luxembourg, Latvia, France, Italy, Spain and Germany. Austria stopped using one particular batch. 

Sorry, I may have lost Bulgaria in there somewhere, and quite possibly a few other countries. I may also have added some, but every last one of the countries I listed exists. I’m almost certain of that. And unless you’re in one of them, you don’t need to worry about whether I have the full list. On the other hand, if you are in one, you’ll have already heard about it from a more reliable source.

C’mon, I’m not a newspaper. I do my best. 

Whatever the full list is, the European medicines regulator says it sees no evidence that the vaccine caused the blood clots. Suspending its use is worrying, it says, because the risk of getting Covid is greater than any risk posed by the vaccine.

It’s worth noting that a fair number of countries haven’t suspended its use and don’t think there’s a danger. And all of them also exist and are completely real. 

Irrelevant photo: alexander

The European Medical Authority’s executive director Emer Cooke said about the blood clots, “At present there is no indication that vaccination has caused these conditions, they have not come up in the clinical trials and they are not listed as known or expected side events with this vaccine.”  

The EMA is looking into the issue more closely and is due to report on Thursday, but it considers a link very unlikely. The World Health Organization also sees no link.

So what’s the story on blood clots? A woman in Denmark died after getting vaccinated. She had a low number of platelets, blood clots in small and large vessels, and bleeding. Another death was reported in Norway, along with a handful of non-fatal cases with similar “unusual” reactions, the Norwegian Medicines Agency said. 

The question in all of this is whether the blood clots are caused by the vaccine or whether they’re unrelated events that happened to happen to people who’d been vaccinated recently, sort of like people deciding to buy jelly beans after they got vaccinated. If you start counting the people who do that, you might find a surprising number, but that wouldn’t be proof that the vaccine caused them to buy jelly beans. The best way to show a link is to compare the number who bought jelly beans to the number of unvaccinated people who did. 

You’ll want to run that experiment in the US, though, where it’s easier to find jelly beans.

Britain hasn’t seen a spike in blood clots despite having pumped more than 11 million doses of the AstraZeneca vaccine into people’s arms.

AstraZeneca–and here I mean the company, not the vaccine–counted 15 incidents of post-vaccination deep-vein thrombosis (a blood clot in a vein) and 22 of pulmonary embolism (a blood clot that’s entered the lungs) in Britain. That is, they said, “much lower than would be expected to occur naturally in a general population of this size and is similar across other licensed Covid-19 vaccines.”

You’re welcome to untangle that sentence if you want. I’m going to quote and run.

No I’m not. It’s the lower and similar that throws me. I think I know what they’re saying but they’d have done better to make two sentences out of that so their points of comparison were clear. 

I know. Everyone’s a critic.

The cheesier end of the British press–which is cheesy indeed–is treating this as an opportunity to wave the flag. We knew those Europeans had it in for us. See what they’re like? So far, though, none of them have proposed sending gunboats to support our flagship vaccine. If they do, I’ll let you know.

 

Variants news

One the other hand, a new double-blind study of 750 people exposed to the South African Covid variant found that the AZ vaccine is only 10.4% effective against mild to moderate cases. On the bright side, though, nobody was hospitalized and a second-generation AZ vaccine is in development that will close that gap in its protective fencing.

*

Two cases of a Covid strain first identified in the Philippines have been found in Britain. It too may be more resistant to vaccines. 

 

And finally, an irrelevant feelgood story

After getting his second vaccination in Massachusetts, cellist Yo-Yo Ma sat down and gave a fifteen-minute concert for health workers and the people waiting in line behind him. 

Ma is internationally known and famous enough that even I know who he is. When he went for his first shot, he scoped out the surroundings, then brought his cello with him for the second shot. 

He wanted to give something back, he said.