This year we kill it: Corona Virus Thread Mark II

[sihnfahl]

Its dropped the efficacy rate from 79% to 76 % (or 80-85% for over 65's)

Which is still good.

I can see the arguments for and against making the little disagreement over data public, and I lean towards 'for' making them public. The people who won't believe wouldn't believe anyway, and those on the fence may feel a little more confident when the folks providing oversight are being transparent about their concerns.

[pendell]

Meanwhile , it seems that Pfizer is equally effective against the new variants . I suspect we'll find the same holds true for moderna as well. I wonder if this implies that in a few years or decades we can use mRNA tech to develop a permanent use-once-never-need-again flu vaccine? The mRNA vaccines seem to do a better job of immunizing the body against multiple variants of the same virus , rather than only one.

Got my first Pfizer shot yesterday. Some wooziness, bad case of the munchies, on nights with a full moon wake up naked in the woods with the taste of blood in my mouth, but I assume all these are expected side effects and will pass.

... right?

Respectfully,

Brian P.

[sihnfahl]

I wonder if this implies that in a few years or decades we can use mRNA tech to develop a permanent use-once-never-need-again flu vaccine?

Maybe, but right now, probably not. Flu has a much higher mutation rate than COVID.

So while COVID isn't changing significantly enough to impact the vaccine efficacy, flu viri change fast enough that eventually the drift will result in needing a new vaccine.

The technology right now just makes it faster to make the vaccines. Two months instead of six.

[Strigon]

Meanwhile , it seems that Pfizer is equally effective against the new variants . I suspect we'll find the same holds true for moderna as well. I wonder if this implies that in a few years or decades we can use mRNA tech to develop a permanent use-once-never-need-again flu vaccine? The mRNA vaccines seem to do a better job of immunizing the body against multiple variants of the same virus , rather than only one.

I suppose it's possible, but I can't imagine how. They both work the same way - introduce a target portion of the pathogen to the body so the immune system can identify that portion later. The only difference between conventional vaccines and mRNA vaccines is how that target portion is introduced to the body - without changing something about what the body is reacting to, or how it reacts, I don't see how any particular method would lead to a more robust vaccine.
But then again, what do I know? I've taken exactly one biology course since leaving high school.

[sihnfahl]

I've taken exactly one biology course since leaving high school.

I believe the logic is as thus:

Current vaccines are developed using the specific virus. The idea of the mRNA vaccine that was proposed is that it can be a more 'generic' vaccine that recognizes multiple similar markers between the flu strains, so it trains the body on the generals, rather than the specifics.

Let's use an analogy to bridges.

Think of Akashi Kaikyō, Golden Gate, Runyang, Humber, etc. - they're all suspension bridges, so, all the same 'family' of bridge in how they stay up.

Someone with the blueprints of the Golden Gate could say 'oh, here's a weak point that'll make it collapse'. But the others don't have that same weak spot due to a design difference. So a plan that relies on that particular weak point would only work on the GG.

But then you study suspension bridges in general and find the common weak points that result just as a fact of physics. Any plan developed using those weak points would bring down all the bridges, not just one specifically.

[NichG]

I believe the logic is as thus:

Current vaccines are developed using the specific virus. The idea of the mRNA vaccine that was proposed is that it can be a more 'generic' vaccine that recognizes multiple similar markers between the flu strains, so it trains the body on the generals, rather than the specifics.

Let's use an analogy to bridges.

Think of Akashi Kaikyō, Golden Gate, Runyang, Humber, etc. - they're all suspension bridges, so, all the same 'family' of bridge in how they stay up.

Someone with the blueprints of the Golden Gate could say 'oh, here's a weak point that'll make it collapse'. But the others don't have that same weak spot due to a design difference. So a plan that relies on that particular weak point would only work on the GG.

But then you study suspension bridges in general and find the common weak points that result just as a fact of physics. Any plan developed using those weak points would bring down all the bridges, not just one specifically.

The way I tend to think about it is, a given virus might have some number of features that the host immune system could pick up on to identify it: A, B, C, D, .... The host isn't going to pick all of these features - one antibody fits one feature, and there's a sort of competitive dynamics so that one is going to win (usually the one with strongest binding affinity I'd guess, but I think it's known that the same virus will produce different winning antibodies in different people so there's likely a big chance element to it all). Now, lets say that one of those features is really essential to the virus and is very hard for evolution to alter without some severe tradeoff, whereas the other features are more mutable. If A gives a really strong binding affinity for antibodies, but D is the highly conserved feature, then the virus can more readily mutate to escape host immunity.

I suppose you could even have an evolutionary pressure to add really chemically distinctive regions to the virus to 'bait' a host immune system into targeting something the virus can easily change, in order to lessen the chance that the host discovers the actual essential structures.

Originally, to prepare a vaccine you basically inactivate the virus and then inject the shards, so its basically the same situation as natural infection where the host is going to see all the different available targets and pick one to go after. I'm not sure if modern peptide vaccine design is like that or if they actually re-synthesize particular structures to target though - but I'd imagine that'd significantly hike up the cost even if we do have the technology to do it.

But with an mRNA vaccine, you have to choose exactly what proteins to present to the host because that's how it works. So that gives you the ability to explicitly make a choice whether the host sees A, B, C, or D. If you understand the mechanisms of the virus well enough to pick correctly, you can improve things compared to using the whole virus. If you pick the wrong thing, it should be worse than using the whole virus. So I'd guess the main advantage is actually being able to study that and turn it into the subject of engineering, rather than just having to take it at random. If you had a virus where it didn't have any highly conserved and chemically distinctive surface structures (or where for example it 'hid' those structures under scaffolding that made it look like part of the host's body, so the host couldn't produce antibodies against it without developing an auto-immune reaction) then it wouldn't help. But if there's a virus that has a lot of distinctive but rapidly changing flak, it might let you beat it.

I was briefly involved with a group studying general vs specialized antibodies in HIV. It seems that a very, very small number of people successfully develop immunity to HIV when exposed, and at the time the reason proposed (which I don't know if it has been borne out or falsified since then) was that they somehow produced broad-affinity antibodies that bound to a lot of different things and so made a big enough net that HIV couldn't mutate its way out, whereas most people made the more specific antibodies. One line of thinking was that the broad-affinity response might have corresponded to a weaker filtering against forming antibodies that attacked self - e.g. most people's immune system would say that that general antibody was too risky, and the corresponding B-cell line wouldn't be activated. But if its instead that there are a bunch of different features and hidden in there is some harder-to-mutate thing that host immune systems struggle to find, then an mRNA vaccine might produce a way to show only that feature.

[pendell]

As I recall, the very earliest vaccine in the 19th century was live-virus cowpox, which immunized humans against smallpox. From what you describe, NichG, it sounds like the reason this worked is because the binding agents in cowpox were similar enough to smallpox that training the immune system on one gave it the tools it needed to fight the other as well.

So what I understand from reading the preceding posts is that mRNA gives us the capacity to do is to exactly tailor the response we are trying to train -- to tell the immune system "this, specifically, is what you should watch out for." If we do it right, the immune system is trained more efficiently than if it chose a random response to shards of the natural virus. And if there are other diseases with the same markers , the vaccine will immunize against those variants as well.

That, perhaps, is why mRNA appears to be more effective than standard -- because in standard there's no guarantee that the immune system will learn to respond to the essential components which are the same in all variants, whereas if we've truly identified the essential components in mRNA, we train the vaccine against all diseases which have those essential components.

Of course, if we commit an error we could produce a vaccine that is useless instead, since we train the immune system to respond to something that isn't part of the disease. It could even be counter-productive, if we train the immune system to respond to something harmless, essentially giving someone an allergy when they had none before.

Which, I suppose, is why we have so much testing before it's shipped and used in human patients.

Respectfully,

Brian P.

[Strigon]

That all makes sense.
I suppose I was under the impression that viral-vector vaccines had essentially used the same spike protein that mRNA vaccines replicated, and would thus provoke the same immune response.

In fact, google has failed to clear up that matter. I understand that mRNA vaccines provoke your body to produce the target antigen, and viral vectors incorporate antigens from the pathogen into a harmless virus, but how do those provoke different responses? Do we just lack the fine control for viral vectors, and have to take what we can get?

[NichG]

That all makes sense.
I suppose I was under the impression that viral-vector vaccines had essentially used the same spike protein that mRNA vaccines replicated, and would thus provoke the same immune response.

In fact, google has failed to clear up that matter. I understand that mRNA vaccines provoke your body to produce the target antigen, and viral vectors incorporate antigens from the pathogen into a harmless virus, but how do those provoke different responses? Do we just lack the fine control for viral vectors, and have to take what we can get?

I would think viral vector vaccines should work the same, so not sure about this. I do know that provoking the right level of immune response and getting the response to go after the antigen rather than the delivery mechanism are important engineering considerations for overall effectiveness. So maybe the response to the nanoparticles and the viral vector are different in that way.

[farothel]

The exact way they work is slightly different, but in general it's the same principle. Have the host make the spike protein so his/her immune system can recognise it. Virus vector vaccines do that by inserting DNA in the host, mRNA vaccines of course by instering mRNA.

[sihnfahl]

Do we just lack the fine control for viral vectors, and have to take what we can get?

Viral vector vaccines pretty just mean we take the entire virus and do something to it to either kill it or make it relatively 'safe' (attenuated). So it throws a lot of fragments into the body, with hopefully enough of the original left that it provokes the right response.

So maybe the response to the nanoparticles and the viral vector are different in that way.

mRNA nanoparticles are more targeted. We get the body to make a LOT of a specific protein of the virus, rather than bits and pieces of, well, everything about the virus. The closer we get to the more significant proteins, and trigger the immune response, the more effective the inoculation.

Inactivated Polio is about as effective as the oral polio vaccine, for example ... but, IIRC, it doesn't prevent the individual from spreading it. Oral vaccines, however, if not treated right, will actually cause vaccine-induced paralysis.

Virus vector vaccines do that by inserting DNA in the host, mRNA vaccines of course by instering mRNA.

Technical difference - inactivated VV can't insert anything. Dead fragments. Course, by being dead, you need boosters of inactivated to get full protection.

Attenuated ones are more effective with a single dose, and they do insert viral DNA into the host (RNA viral infections still do the insertion thing) ... but that does carry the chance that an incompletely attenuated virus can go 'live' again.

[DavidSh]

Viral vector vaccines pretty just mean we take the entire virus and do something to it to either kill it or make it relatively 'safe' (attenuated). So it throws a lot of fragments into the body, with hopefully enough of the original left that it provokes the right response.

I don't think you have that right. The CDC says

Many vaccines use a weakened or inactivated form of the target pathogen to trigger an immune response. Viral vector vaccines use a different virus as a vector instead, which delivers important instructions (in the form of a gene) to our cells. For COVID-19 vaccines, a modified virus delivers a gene that instructs our cells to make a SARS-CoV-2 antigen called the spike protein. This antigen triggers production of antibodies and a resulting immune response. The virus used in a viral vector vaccine poses no threat of causing illness in humans because it has been modified or, in some cases, because the type of virus used as the vector cannot cause disease in humans.

[sihnfahl]

I don't think you have that right. The CDC says

Ergh, you're right. I'm thinking of a different concept.

[sktarq]

er the attenuated aspect is kinda vague. Attenuated covers a lot of ground. So sometimes the virus is "killed" (in quotes because the status of viruses as alive is a edge case with people on either side) and sometimes weakened via chemical means, sometimes all it needs is sunlight, and sometimes even gene modified to be less virulent. (yes this mean gene splicing Frankenstein virus and then infecting people with them is a thing we do on the regular). In fact a couple of the COVID-19 vaccines are like this where the COV-SARS2-19 spike protein is gene grafted into a common cold corona virus (This is that Viral Vector type). You may hear of "live virus vaccines" which do cause the host cells to create and thus be able to fight a very similar virus to the targeted one (So those do inject DNA/RNA (depending on virus type) into cells. This is what the mRNA vaccines are somewhat trying to do as well just with a single part of virus instead of the whole thing. Dead viruses generally don't get their DNA/RNA into cells to be majorly replicated and flood the vascular system with enough irritants and "help i'm infected" chemicals that infected cells would normally produce to kick the immune system into high gear to attack the virus floating in the blood (dead or not). To make it more complex lots of these terms are more descriptive a trait or manufacturing process than an true organizational system so there can be lots of overlap that is weirdly specific to each case...so the viral vector type may cause your cells to make more of modified viral line or just the targeted protein, may or not be attenuated in some other way or may be blasted to bits and used as a deactivated virus vaccine (I don't know of any who use this last method but it would be possible). The terminology is not exactly intuitive either.

As for oral polio...well that is a live vaccine. It can even get passed on to other people in the environment in the same way the wild one can (if much less effectively). It is basically a mutant line of polio that won't hurt you. But being an active virus it can also mutate. And it can mutate back into a very nasty form again (but generally still not good at passing itself on) which is the main source of polio vaccine paralysis we see.

[Bartmanhomer]

I've been fully vaccinated about two weeks ago and I'm still wearing a mask: Why do I have to keep wearing the mask even I'm fully vaccinated now? It doesn't make any sense anymore.

[Mystic Muse]

I've been fully vaccinated about two weeks ago and I'm still wearing a mask: Why do I have to keep wearing the mask even I'm fully vaccinated now? It doesn't make any sense anymore.

Because you aren't fully immune, and I believe there's a concern that you could still transmit it even if you can't catch it yourself.

Believe me, I am so damn sick of wearing a mask. I have wanted to stop for months. Please hold out for just a few more months.

[Bartmanhomer]

Because you aren't fully immune, and I believe there's a concern that you could still transmit it even if you can't catch it yourself.

Believe me, I am so damn sick of wearing a mask. I have wanted to stop for months. Please hold out for just a few more months.

Well, I'm glad that you agree with me for once and I hope that this face mask trend isn't a permanent one. I feel like that a wizard has cast a spell on me with a face mask attachment spell with permanency effect to it.

[snowblizz]

You know you are vaccinated, but no one else does. If you don't wear a mask well then I won't either but I'm not vaccinated. It's an everyone does or no one situation really.

Or maybe all the people who are or are not vaccinated need some marker on their clothes, maybe yellow star? Because singling people out never lead to a bad place.


I was watching a youtube commentator showing a focus group of people of sceptical of vaccine who insisted masks needed to come off because vaccinations has been done. But you know none of them have had it, and will their immediate surrounding be likewise?
Basically, say they are vaccinating in Oregon, well that doesn't mean masks can come off in Florida.

[farothel]

er the attenuated aspect is kinda vague. Attenuated covers a lot of ground. So sometimes the virus is "killed" (in quotes because the status of viruses as alive is a edge case with people on either side) and sometimes weakened via chemical means, sometimes all it needs is sunlight, and sometimes even gene modified to be less virulent. (yes this mean gene splicing Frankenstein virus and then infecting people with them is a thing we do on the regular). In fact a couple of the COVID-19 vaccines are like this where the COV-SARS2-19 spike protein is gene grafted into a common cold corona virus (This is that Viral Vector type). You may hear of "live virus vaccines" which do cause the host cells to create and thus be able to fight a very similar virus to the targeted one (So those do inject DNA/RNA (depending on virus type) into cells. This is what the mRNA vaccines are somewhat trying to do as well just with a single part of virus instead of the whole thing. Dead viruses generally don't get their DNA/RNA into cells to be majorly replicated and flood the vascular system with enough irritants and "help i'm infected" chemicals that infected cells would normally produce to kick the immune system into high gear to attack the virus floating in the blood (dead or not). To make it more complex lots of these terms are more descriptive a trait or manufacturing process than an true organizational system so there can be lots of overlap that is weirdly specific to each case...so the viral vector type may cause your cells to make more of modified viral line or just the targeted protein, may or not be attenuated in some other way or may be blasted to bits and used as a deactivated virus vaccine (I don't know of any who use this last method but it would be possible). The terminology is not exactly intuitive either.

As for oral polio...well that is a live vaccine. It can even get passed on to other people in the environment in the same way the wild one can (if much less effectively). It is basically a mutant line of polio that won't hurt you. But being an active virus it can also mutate. And it can mutate back into a very nasty form again (but generally still not good at passing itself on) which is the main source of polio vaccine paralysis we see.

Correct, only the common cold vectors they use are not corona- but adenoviruses. At least at J&J they use an Adenovirus.

[Tyndmyr]

I've been fully vaccinated about two weeks ago and I'm still wearing a mask: Why do I have to keep wearing the mask even I'm fully vaccinated now? It doesn't make any sense anymore.

Inertia, largely.

The vaccine is, while not perfectly effective in all circumstances, still quite effective, far more so than a mask. Most recent CDC study on mask mandates has them correlated with a long term .9% reduction of death rate if memory serves. Masks AND restaurant closures combined were a 1.6% reduction*. Vaccines vary in effectiveness depending on strain and type, but a most circumstances are expected to be mid 70%ish effectiveness or better.

As vaccination + natural immunity become common, R should sink far below zero and infection rate should fall off a cliff. Mask wearing in addition to vaccines won't impact this all that much(extremely low marginal improvement), but going and getting a vaccine if you are unvaccinated will.

We may still have a seasonal bump before we get enough vaccinated, though.

*Full disclosure: The end date of the study may indicate p-hacking. Different end dates get somewhat different results, generally with lower effectiveness for masks and other policies. However, this is largely tangential to the whole "vaccines are more critical" point.

[asda fasda]

Inertia, largely.

I don't think that's right, the mask is still needed because there are not enough evidence whether vaccines (or which one) reduce the probability of getting sick and spreading the diseases or only make you less probable of severe sickness and death. In other words you should wear mask in order to limit spreading the diseases which could kill someone who is not vaccinated.
Additionally with every new case there is a risk of mutation that will be resistant to vaccines, so it's better to keep down the number of cases.

[Tyndmyr]

I don't think that's right, the mask is still needed because there are not enough evidence whether vaccines (or which one) reduce the probability of getting sick and spreading the diseases or only make you less probable of severe sickness and death. In other words you should wear mask in order to limit spreading the diseases which could kill someone who is not vaccinated.
Additionally with every new case there is a risk of mutation that will be resistant to vaccines, so it's better to keep down the number of cases.

That seems...deeply unlikely, because preventing the spread is largely how vaccines work. There isn't any real reason why we should suspect that these vaccines would make you a carrier, any more than we should expect some interaction that makes your head explode or something.

We routinely vaccinate against far more virulent diseases, and herd immunity is a fairly predictable, well established result of this vaccination.

[Chen]

That seems...deeply unlikely, because preventing the spread is largely how vaccines work. There isn't any real reason why we should suspect that these vaccines would make you a carrier, any more than we should expect some interaction that makes your head explode or something.

We routinely vaccinate against far more virulent diseases, and herd immunity is a fairly predictable, well established result of this vaccination.

The research has not yet shown if the Covid vaccines provide sterilizing immunity (preventing infection) or simply effective immunity (preventing disease). As such preventing possible transmission until the majority of people are vaccinated is still warranted hence continued mask use.

[Keltest]

The research has not yet shown if the Covid vaccines provide sterilizing immunity (preventing infection) or simply effective immunity (preventing disease). As such preventing possible transmission until the majority of people are vaccinated is still warranted hence continued mask use.

Ehhh... continued mask use due to being unable to honestly identify vaccinated vs unvaccinated seems a lot more likely to me. The people mandating the masks aren't doctors and are more likely to take the social factors of spread into account than the scientific ones.

[asda fasda]

That seems...deeply unlikely, because preventing the spread is largely how vaccines work. There isn't any real reason why we should suspect that these vaccines would make you a carrier, any more than we should expect some interaction that makes your head explode or something.

We routinely vaccinate against far more virulent diseases, and herd immunity is a fairly predictable, well established result of this vaccination.

Yes, but with vaccines that were tested for years during the development and for diseases that were carefully studied for years. As for COVID at this point there is no reliable data to conclude whether vaccines limit spreading as the tests were focused on severe sickness, those 9X% that they show on news is the percentage drop in severe sickness. Most likely this also limits the ability of virus to transmit but as this is much harder to track we just don't know how much.

As for me mask will stay even after everyone around me are vaccinated. It amazing to me that as the pandemic started people was like "well flu also kills X thousand people a year, what's big deal", when I was "wait, flu is killing people ? wtf? and the mask could help? why were we not wearing masks before ?"

[akma]

As for me mask will stay even after everyone around me are vaccinated. It amazing to me that as the pandemic started people was like "well flu also kills X thousand people a year, what's big deal", when I was "wait, flu is killing people ? wtf? and the mask could help? why were we not wearing masks before ?"

I heard that in Japan (and maybe other east Asian countries) it is the custom to walk around with a mask when you're sick. I'm guessing this custom will somewhat spread to other countries after the Coronavirus will finally die down.
The way people think of death of strangers is weird and doesn't make mathematical sense. Wars and massive riots can start because of a regrettable death of a few unimportant individuals (or even of one), but people are completely indifferent to things that kill many people every day.

[NichG]

Yes, but with vaccines that were tested for years during the development and for diseases that were carefully studied for years. As for COVID at this point there is no reliable data to conclude whether vaccines limit spreading as the tests were focused on severe sickness, those 9X% that they show on news is the percentage drop in severe sickness. Most likely this also limits the ability of virus to transmit but as this is much harder to track we just don't know how much.

The data from Israel could give us a good bead on this, if we look specifically at the rate of occurrence in the non-vaccinated populations. I was worried when it looked like their cases per day was holding constant, but about two months after they started giving out doses it started to tank. Another data source over the next few months may be Bhutan, which reserved doses and then vaccinated something like 30% of its population in a single day. So there should be a nice sharp time signal there, which might be more blurred out in other places that were doing the rollout as doses came in.

As for me mask will stay even after everyone around me are vaccinated. It amazing to me that as the pandemic started people was like "well flu also kills X thousand people a year, what's big deal", when I was "wait, flu is killing people ? wtf? and the mask could help? why were we not wearing masks before ?"

I heard that in Japan (and maybe other east Asian countries) it is the custom to walk around with a mask when you're sick. I'm guessing this custom will somewhat spread to other countries after the Coronavirus will finally die down.
The way people think of death of strangers is weird and doesn't make mathematical sense. Wars and massive riots can start because of a regrettable death of a few unimportant individuals (or even of one), but people are completely indifferent to things that kill many people every day.

Yeah, I lived in Japan for the last 6 years and masks were basically all over, and wearing one when you were coughing or whatever was common courtesy. I think some people even wore them for allergies or when the air was dry (no clue whether it'd help even a bit there). So I got pretty used to the custom, and it makes sense to me to keep it. I think it helps a lot to occasionally see a mask in public on a weekly basis to not build associations like 'something is wrong with this person' or 'are they trying to hide their identity' or whatever.

I sort of hope the gel-seal mask design becomes cheaper and more standard. It looks like it would solve the glasses fogging thing, but given how little I actually need to interact with other people face to face and that I have a few N95s left that I brought with me from Japan for those situations, I kind of can't justify getting one at this point...

[akma]

The data from Israel could give us a good bead on this, if we look specifically at the rate of occurrence in the non-vaccinated populations. I was worried when it looked like their cases per day was holding constant, but about two months after they started giving out doses it started to tank. Another data source over the next few months may be Bhutan, which reserved doses and then vaccinated something like 30% of its population in a single day. So there should be a nice sharp time signal there, which might be more blurred out in other places that were doing the rollout as doses came in.

There is probably going to be a spike in the cases in Israel soon, since it's Passover now. Schools are closed and many people don't work this week, and a lot of them go outside and on trips. Going to Jerusalem is very common in this holiday, so that means more crowdedness in a specific area.
Also, the populations with the highest infection rates are also the ones less likely to want to get vaccinated. Although with some specific groups, with the amount of carelessness displayed, maybe they already developed herd immunities on their own.

[Tyndmyr]

The research has not yet shown if the Covid vaccines provide sterilizing immunity (preventing infection) or simply effective immunity (preventing disease). As such preventing possible transmission until the majority of people are vaccinated is still warranted hence continued mask use.

This is akin to the current news saying that the vaccine is only valid for 90 days.

Realistically, the vaccine is almost certainly effective for far longer. It's just that the study was only 90 days long, because long studies slow deployment, and we needed to get this stuff rolling. There's no actual reason to suspect that immunity ends the day after the study did.

I am not aware of any vaccine in use that prevents the illness without impacting transmission. Given that these vaccines are not wholly novel in how they're made, we should expect them to work in the same fashion as existing vaccines, not in some entirely unusual way. All existing data is consistent with this, even if it's not wholly proven.

[Strigon]

This is akin to the current news saying that the vaccine is only valid for 90 days.

Realistically, the vaccine is almost certainly effective for far longer. It's just that the study was only 90 days long, because long studies slow deployment, and we needed to get this stuff rolling. There's no actual reason to suspect that immunity ends the day after the study did.

I am not aware of any vaccine in use that prevents the illness without impacting transmission. Given that these vaccines are not wholly novel in how they're made, we should expect them to work in the same fashion as existing vaccines, not in some entirely unusual way. All existing data is consistent with this, even if it's not wholly proven.

Honest question: do you expect you'd know of such a vaccine if it existed? Or, perhaps more relevant, what about vaccines that aren't in use? Because it's conceivable that vaccines were developed that had little or no effect on transmission, but were later replaced by vaccines that did reduce transmission once they became available.

I don't know either way, but it seems at least plausible that preventing transmission isn't a guarantee with vaccines for illnesses where asymptomatic transmission is possible, and that our current vaccines only do that because we've had the time to perfect them.