Tag Archives: breakthrough Covid infections

What does it mean that a Covid vaccine is, say, 70% effective?

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Let’s start by talking about what it doesn’t mean. If a vaccine is 70% effective against a virus it doesn’t mean that 30% of the people who’ve been vaccinated will get infected. That’s an assumption that only people whose math is as bad as mine would make. The kind of people who juggle the numbers 70, 30, and 100 and come up with an answer that’s as likely looking as it is meaningless.

It turns out that the number doesn’t compare the vaccinated people who stay well to the  vaccinated people who get sick. Nay, verily, it compares the vaccinated people who get sick (or who stay well) to the unvaccinated people who get sick (or who stay well). To put that a different way (because I don’t know about you, but I’m struggling with this), it compares the risk vaccinated people run in the presence of Covid to the risk unvaccinated people run.

This matters because it leaves us with a much smaller pool of people who are vulnerable.

If you’d care to read about that with actual numbers and sensible writers, follow the link. I have a severe allergy to math and I know better than to attempt a full explanation. 

Irrelevant photo: Red clover. I’ll come back with more kitten photos soon.

 

Who gets sick with the Delta variant and can the vaccinated spread it?

In the US, 95% to 98% of the people hospitalized with Covid are unvaccinated, and 99.5% of the deaths are of the unvaccinated. Even with the Delta variant circulating, that seems to be holding true.

But some numbers have changed since the initial vaccine studies, and they have to do with what Dr. Robert Schooley, from the Department of Medicine at UC San Diego’s School of Medicine, calls “the asymptomatic shedding rate among vaccinated individuals,” which in human speech means how much of the virus is spread by vaccinated people who get infected but don’t get sick.

Or to push that one step further, how dangerous they are to the unvaccinated.

When the vaccines were tested, the Delta variant wasn’t around yet. They were dealing with a less infectious beast. On top of which, no one thought to investigate the odd sniffles and colds that people in the study cooked up. They were allergies. They were colds. They were flu. 

Remember the old days, when people caught colds? 

So the study didn’t track them.

Now, though, they’re realizing that those mild symptoms could be nearly asymptomatic Covid, and what’s known so far is that some fully vaccinated people who get infected carry enough of the virus to spread it, even though it’s not making them sick.

How do they compare with unvaccinated people as far as spreading the thing goes? The numbers aren’t in yet. I mean, they’re out there. Numbers always are. But nobody’s assembled them yet. On average, though, Schooley says the infected vaccinated person will shed less virus for a shorter time. And the odds that they’ll become infected are lower, so whatever the eventual picture turns out to be, vaccinating people does slow the spread of the disease.

 

Are the vaccines losing their effectiveness? 

As has become usual since the pandemic started, we’re not likely to find a definitive answer yet, but it does look like the number of breakthrough cases in vaccinated people is growing.

What’s a breakthrough case? A Covid case in someone who’s vaccinated. Getting one doesn’t mean you’re dead, hospitalized, or even necessarily sick. It just means you’re carrying the infection, when if the vaccines were 100% effective (very few are and no one expected these to be), you wouldn’t be. 

So if you’re fully vaccinated, it’s not time to panic yet. You can always do that later. 

Why’s this happening? The experts are still debating that, but it doesn’t look like the Delta variant is evading either the vaccines or immunity from earlier infections. 

That’s another reason to wait before you panic.

If Delta hasn’t broken through the vaccines’ protective lines, that leaves us with two possibilities. One, the vaccines’ effectiveness is fading, or two, Delta’s high transmissibility is responsible.

Several studies show what could be a waning in vaccine effectiveness, but it’s hard to know if the numbers really mean that. They could also mean that vaccinated people are taking more risks–going to bars or gyms or other Covid exchange sites–and giving themselves more chances to meet the virus.

And protection against getting so sick that you need to be hospitalized, though, is holding steady, which may mean effectiveness isn’t waning. All this will be perfectly clear in hindsight, but for now we have to make do with what we can see from where we are.

So do booster shots make sense? 

On the side of saying no are the many countries that the vaccines have barely reached. How can rich countries be talking about booster shots when initial doses are desperately needed elsewhere?

On the side of saying yes is that in people with weakened immune systems, because of either age or disease, they can make a difference, although the evidence on that is still preliminary.

 

Testing news

A new study shows that testing saliva for Covid is as reliable as testing nasal swabs. So at some point we may be able to stop puncturing our brain pans with sticks that are allegedly softened with cotton wool–or something that looks vaguely like cotton wool.

If Covid tests shift to using saliva, they won’t have to rely on patents’ willingness to make themselves uncomfortable, which will make them more reliable. And we won’t have to worry about a shortage of swabs.

If, in fact, worrying about that is one of the things that’s keeping you up at night.

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Several times now, I’ve sworn off writing about newer, faster, cheaper Covid tests because although I keep reading about them, they never seem to be adopted–at least not anywhere I read about, and certainly not where I live. But you know how it is when you swear off something multiple times: It’s a sign that you keep breaking your word. So here we go again:

A newer, faster, cheaper Covid test has been developed. And it uses the same stuff that pencil lead is made from, which isn’t lead at all, it’s graphite. It cuts the cost to $1.50 per test, takes six and a half minutes, and is 100% accurate using a saliva sample and 88% using one of those evil nasal thingies.

The system can be adapted to test for other transmissible diseases. Now all we have to do is wait and see whether we hear of it again.

Can fermented soybeans destroy Covid?

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It’s too early to celebrate this, but from Japan comes the news that an extract made from natto–a sticky food involving fermented soybeans–inactivates Covid’s spike protein by digesting the receptor binding domain.

What’s a receptor binding domain? No idea, but Covid’s spike protein needs it, so anything that digests it has got to be good–at least from our point of view.

The extract of natto works on all the existing variants.

The reason it’s not time to celebrate is that so far it’s only worked in a lab. No one’s gotten the natto and the virus together inside the body. Eating natto won’t help. Neither will sending the virus invitations to a party and serving natto hor d’oeuvres. No matter how much it mutates, the virus will continue to be illiterate, so it won’t show up.

Irrelevant photo: a wild orchid.

The next stage is to isolate the molecular mechanism that’s destroying the–what was that called?–the receptor binding domain. Figure that out and you could well have a treatment for Covid. 

Possibly. At some time in the indistinct future. But c’mon, we need all the hope we can find.

 

England’s world-beating experiment in irresponsible government

On July 19, England took what little common sense it had forgotten in the drawers of 10 Downing Street’s desks and set it on fire. It’s been dry lately, but there wasn’t enough common sense to burn for long, so we didn’t get the second Great Fire of London, just another round of Covid stupidity.

To be clearer about this, nightclubs are now open. So are bars, restaurants, and pretty much everything else you can think of. It’s up to you whether to throw your mask away and sit nose to nose, indoors, and sing loudly with six of your favorite strangers and no ventilation. Or with thirty of them if you can get your noses close enough. Crowd limits are out of fashion, along with distancing. 

The first day of that was called Freedom Day. Those of us currently cowering under the covers are free to cower under the covers. Unless of course we have to go to work or in other ways mix with the rest of humanity.

The official justification for this is that vaccination has severed the link between infection and hospitalization. Or weakened it, depending on when you listen to the explanations and who gives it. We have to return to normal life. We have to live with Covid. The economy needs us. And if not now, when? 

Maybe when it’s safe, that’s when. Because the link between infection and hospitalization hasn’t been severed, it’s only been weakened, and that’s not enough. The number of infections is going up, and so is the number of deaths. Not as sharply as it once would have, but more than it would if we kept to a marginally sensible policy.

And the thing about deaths is that once people are dead, they’re gone. It’s kind of irreversible.

The government’s Scientific Advisory Group warns that the combination of a large number of vaccinated people and a high number of infections creates the perfect conditions to create a variant that will escape the vaccines. No one can know whether that will happen–vaccines mutate randomly–but the likelihood increases as the number of infections increases.

And while all this is shoving us in one direction, Boris Johnson says vaccine passports will be required for nightclubs etc.–but not until the end of September. Between now and then, let Covid rip.

What are they thinking? One of the government’s scientific advisors, Robert West, says it’s “a decision by the government to get as many people infected as possible as quickly as possible, while using rhetoric about caution as a way of putting the blame on the public for the consequences.” 

That wave of infections would combine with the number of vaccinated people to push the country toward herd immunity and the virus would no longer spread.

What are the problems with the strategy? Well, in addition to opening the doors to a variant that evades the vaccines, no one knows what level of immunity is needed for herd immunity to Covid. The best guess is 85%. And then there’s long Covid–the long-term damage that some people live with for no one knows how long, after even asymptomatic infections. 

The government says that’s not its strategy. You’re welcome to believe it if you like. 

And a unicorn just pranced down the street outside my window. You’re welcome to believe that as well. It was wearing a tutu and singing a Mozart aria.

Not long ago, the Netherlands opened everything up and Covid infections rose sevenfold. They’ve since closed bars, restaurants, and nightclubs.

England’s reopening has caused the Covid tracing app to warn an annoying number of people that they’ve been exposed to Covid and should self-isolate–more than 600,000 last week–and that in turn has led to a lot of people being off work.

So what’s a responsible government to do about that? 

We don’t have one of those, so who cares? Instead of deciding that too many people are being exposed to Covid because we took all our restrictions out and burned them, the government’s decided that too many people are being notified, so it’s created a list of crucial occupations whose employees can ignore the app if they’re double vaccinated–although they will at least have to test themselves. 

Can people who are doubly vaccinated spread Covid? Why look! It must be time to talk about breakthrough infections! Because buried in that segment somewhere is the news that we don’t have a clear answer to that question yet.

 

Breakthrough infections

First we need a definition of a breakthrough infection, even if you already know it: A breakthrough infection happens when a vaccinated person gets Covid–or (it can happen with any matched pair of disease and vaccination) whatever else they were vaccinated against. When that happens, it doesn’t mean the vaccine isn’t effective. It means the vaccine isn’t 100% effective, much as we wish the Covid ones were. 

That leaves us–or me anyway–wondering why one person will get a breakthrough infection and another won’t. The definitive answer is that it’s hard to say.

Thanks, Ellen. That was really helpful.

Sorry, but I can only pass on what I find. The direct quote is, “It’s difficult to determine why any particular breakthrough case happens.” 

How large a dose of the virus you’re exposed to might make a difference–with the emphasis on might. Our individual immune systems will make a difference. They can be affected by health problems and by medications that make an immune system respond to the vaccine less enthusiastically.

And new variants can make a difference. The vaccines were developed for the Covid 1.0, or 2.0. We’re now onto–

Hang on a minute. I have to go look up the Greek alphabet and figure out where Delta comes. 

We’re now at Covid 4.0.

It’s also possible for a person to have gotten a vaccine dose that wasn’t administered correctly, although that’s a lot less likely. And no, I’m not sure how you administer a vaccine the wrong way either. Maybe you let the stuff get too warm. Maybe you let it expire. Maybe you miss the arm entirely and inject it into the hat. That last one is the reason they don’t let me do vaccinations anymore.

People who are (fortunately) better than I am at figuring this stuff out are tracking the number of breakthrough infections, looking for evidence that the vaccines’ are wearing thin and booster shots are needed. So far, they haven’t seen it. 

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We can break breakthrough infections into a few categories, and in order of decreasing likelihood they are: 1, testing positive, 2, having a mild infection, 3, having a serious infection, and 4, dying.

Patients are strongly advised to keep themselves out of category 4. 

If you’ve absorbed that advice–and it is important–we’ll move on to the question of whether fully vaccinated people who’ve been exposed to the virus should have to go into isolation. In the US, the Centers for Disease Control (citing “limited evidence” according to the article I found) says they not only don’t need to go into isolation, they don’t need to get tested unless they develop symptoms. The theory is that they’re less likely to infect other people than unvaccinated people with asymptomatic infections.

Other countries are making different rules.The evidence is limited, the lights are off, and we’re all bumping into the furniture. 

What percentage of fully vaccinated people test positive after being exposed to Covid? If anyone has numbers on that, I haven’t found them.

What does seem to be well established is that breakthrough infections are rare, and we do have statistics (sort of) for categories 3 and 4–the one you want to stay out of and the other one you want to stay out of. In the US, 5,492 vaccinated people were either hospitalized or died and also tested positive for coronavirus. That doesn’t exactly say they were hospitalized for or died of Covid, but it’s as close as we’re going to get. That’s 5,492 out of the 159 million people who’ve been fully vaccinated. I’ll leave someone else to figure out what percent that is and just say it’s small.

Most breakthrough infections are mild, and the number of mild or asymptomatic infections will be larger, but again if numbers are available for that I haven’t found them.

 

A different way to live with Covid

Is it possible to return to normal life in some sane and safe way? A study from Barcelona points us toward a possibility. It followed the 5,000 people who attended a carefully controlled indoor concert. 

People were screened on the way into the concert, using an antigen-detecting rapid diagnostic test (it’s called an Ag-RDT if you want to sound like you know what you’re talking about), and the test was done by nurses. At least with other rapid Covid tests, that makes it more reliable than when people do it themselves, probably because they maneuver those nasty swabs into the right spots.

Everyone wore masks–specifically, filtering facepiece 2 masks–the whole time. Presumably over their noses and mouths, not their chins or back pockets. They look like this.  (I’m conducting a one-person boycott of Amazon, but I’m not above using them as a link if I don’t have to give them money.) They’re a kind of mask that offers more protection than your average cloth mask, but they’re disposable, which if everyone used them everywhere would create its own set of problems. Especially since a few of us out there hate throwing things away when they still look usable. 

But enough of that. Let’s move on.

The event’s described as a concert but people danced. People sang (presumably along with the music but it shouldn’t really matter from a medical point of view.) No one was asked to keep 6 feet away from anyone, at least by the organizers, although some predictable number of individuals will have told some predictable other number of individuals to back off. 

I don’t have details on the ventilation except for a passing mention of improved ventilation. Ventilation’s probably the most overlooked way to make work and public spaces safe. 

The event was held in an area that at the time had a moderate rate of Covid and a low number of vaccinated people. 

What happened? The followup found 6 cases of Covid two weeks after the event. Three of those were traced to sources other than the concert. Another person may have been in the incubation stage when she attended the event and could’ve been missed by the test. No one’s figured out where the other two cases came from. 

Which isn’t bad for 5,000 people. So it can be done if we have the will to do it.

 

. . . and in the schools

In the US, the American Academy of Pediatrics is calling for all students, teachers, and staff to wear masks in school, whether they’ve been vaccinated or not. That runs counter to Centers for Disease Control advice, which exempts the vaccinated and says the unvaccinated should wear masks in school to protect themselves.

Even though–apologies, CDC–your average mask is better at protecting people around the wearer than at protecting the person sporting one.

The article I got this from has the first statistics I’ve seen on how many kids get multi-system inflammatory condition (called MIS-C, in case you have any need to address it directly): It’s 1 out of every 600 infected children and teenagers. That’s not the same as 1 out of every 600 kids, only out of the ones who get infected.

MIS-C is seriously serious and more often than not will land a kid in intensive care. It comes several weeks after the primary infection.

Real-world information on Covid vaccine effectiveness

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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.