Regarding the question to what extent a vaccine will be able to prevent infection or primarily reduce the symptoms one of Germany’s leading virologist, Christian Drosten, made some interesting remarks in his regular podcast this week on public radio
(own translation with the help of deepl.com):
“Q: Is there also hope for such vaccines, which actually stop the virus completely, because they can elicit an immune response that is the same as in a real natural infection?
Christian Drosten: With the current vaccines that are currently being tested, this will probably not work. We are dealing here with an infection of the mucous membrane, i.e. in the nose and throat and then later in the lungs—or in the bronchial system, which is more likely to be mucous membrane. And the mucous membranes already have their own special local immune system. With the current vaccines, which are more likely to be administered to the muscles, this local immune system is not as easily reached, i.e. not in the special way. There one has more the general immune effect for the whole body, thus for the systemic spread and also for a part of the general immune response. For example the IGA-antibodies, which then already arrive. IGG antibodies also arrive in the lungs, for example, especially in the context of an incipient inflammation. And this is what the current vaccines do, which probably protect against the severe course of the disease rather than against the infection in general. That’s the most important thing we have to do for the time being. There won’t be one vaccine for everyone in the beginning anyway. Of course, we have to provide the people at risk with a vaccine and take away the dangerous course of the disease, so that the virus will then lose this high death rate in the population.
Q: If we want to contain the spreading at the same time or at a later stage with vaccines, then one must directly go to the mucous membranes.
Christian Drosten: You definitely have to. One can perhaps imagine it in such a way, the next generation of the vaccines must also contain that.
...
Q: How we get to the mucous membranes.
Christian Drosten: In general this is what we would like to have, vaccines that protect the mucous membranes. That stimulate the special immune system there, so that in the future someone, if he breathes a whole load of virus into the nose, is not infected at all, thus does not get only a mild infection, but no infection at all. The virus is immediately stopped in the nose. And the good news is that some of the vaccines now being tested already contain that. They would even be able to do that already. There is an interesting study that proves this. But in principle, we have known that for quite some time, because these are vector vaccines. In other words, there are always vaccines that are mediated via a viral vector.
Q: Another carrier virus.
Christian Drosten: Exactly, where there is a carrier virus. Only one component of the SARS2 virus is added to this carrier virus, namely the surface protein. These carrier viruses often have the property that they can penetrate mucous membranes. So there is no need to inject them into the muscle with a syringe. In principle, they can also be put into a nasal spray, and on the mucous membrane, they enter the cells in the nose and develop their effect there. But at the moment we don’t know anything about the side effects and this has to be looked at carefully. So we have to choose the same study order again. For many of these vector vaccines in humans, we do not yet have this mucosal experience, although we actually know from the animal model that this is what they provide.”
There already exists such a nasal spray vaccine for influenza. And there is some hope for developing something like this for the common cold in the long run.
I have translated another part of the podcast mentioned above, about this subtopic:
“Christian Drosten: There are vaccines where this is already being done. For example, there is a nasal spray vaccine for influenza that can also be used in Germany. That is coming more and more. These mucous membranes, these nasal spray vaccines, are always genetically modified vaccines, i.e. carrier virus vaccines. This has not yet been recognized by the regulatory authorities long enough for it to be safe. Fifteen years ago, there were still great reservations about this, and today, with the increasing success of these carrier virus vaccines, especially in this SARS2 pandemic, these carrier virus vaccines are already quite successful in clinical trials. In the case of Ebola, they have been very successful. And now that more such good experiences are being made, it is to be hoped that more nasal spray vaccines will soon be available. And of course, this is then possibly also as an entry into a cold vaccination in the future. With the many cold viruses that we have, more than 15 viruses that can be listed, we may at some point come to a situation where we have nasal spray vaccines against almost all of them, especially for the adult population. So I think it is not unwise for the children to go through these harmless infections for certain immunological reasons. But for the adults these infections are in some cases anything but harmless. One has to imagine for the economy how many days of sick leave in an economy are caused by the whole bouquet of cold viruses every year. If one could vaccinate against them, that would be an incredible success.”
Regarding the question to what extent a vaccine will be able to prevent infection or primarily reduce the symptoms one of Germany’s leading virologist, Christian Drosten, made some interesting remarks in his regular podcast this week on public radio (own translation with the help of deepl.com):
“Q: Is there also hope for such vaccines, which actually stop the virus completely, because they can elicit an immune response that is the same as in a real natural infection?
Christian Drosten: With the current vaccines that are currently being tested, this will probably not work. We are dealing here with an infection of the mucous membrane, i.e. in the nose and throat and then later in the lungs—or in the bronchial system, which is more likely to be mucous membrane. And the mucous membranes already have their own special local immune system. With the current vaccines, which are more likely to be administered to the muscles, this local immune system is not as easily reached, i.e. not in the special way. There one has more the general immune effect for the whole body, thus for the systemic spread and also for a part of the general immune response. For example the IGA-antibodies, which then already arrive. IGG antibodies also arrive in the lungs, for example, especially in the context of an incipient inflammation. And this is what the current vaccines do, which probably protect against the severe course of the disease rather than against the infection in general. That’s the most important thing we have to do for the time being. There won’t be one vaccine for everyone in the beginning anyway. Of course, we have to provide the people at risk with a vaccine and take away the dangerous course of the disease, so that the virus will then lose this high death rate in the population.
Q: If we want to contain the spreading at the same time or at a later stage with vaccines, then one must directly go to the mucous membranes.
Christian Drosten: You definitely have to. One can perhaps imagine it in such a way, the next generation of the vaccines must also contain that.
...
Q: How we get to the mucous membranes.
Christian Drosten: In general this is what we would like to have, vaccines that protect the mucous membranes. That stimulate the special immune system there, so that in the future someone, if he breathes a whole load of virus into the nose, is not infected at all, thus does not get only a mild infection, but no infection at all. The virus is immediately stopped in the nose. And the good news is that some of the vaccines now being tested already contain that. They would even be able to do that already. There is an interesting study that proves this. But in principle, we have known that for quite some time, because these are vector vaccines. In other words, there are always vaccines that are mediated via a viral vector.
Q: Another carrier virus.
Christian Drosten: Exactly, where there is a carrier virus. Only one component of the SARS2 virus is added to this carrier virus, namely the surface protein. These carrier viruses often have the property that they can penetrate mucous membranes. So there is no need to inject them into the muscle with a syringe. In principle, they can also be put into a nasal spray, and on the mucous membrane, they enter the cells in the nose and develop their effect there. But at the moment we don’t know anything about the side effects and this has to be looked at carefully. So we have to choose the same study order again. For many of these vector vaccines in humans, we do not yet have this mucosal experience, although we actually know from the animal model that this is what they provide.”
Trials of several of the adenoviral vectored vaccines for nasal inhalation have already begun.
Thanks! This is very interesting.
Wouldn’t this apply to other respiratory viruses? Does it?
Is influenza not “an infection of the mucous membrane” too?
There already exists such a nasal spray vaccine for influenza. And there is some hope for developing something like this for the common cold in the long run.
I have translated another part of the podcast mentioned above, about this subtopic:
“Christian Drosten: There are vaccines where this is already being done. For example, there is a nasal spray vaccine for influenza that can also be used in Germany. That is coming more and more. These mucous membranes, these nasal spray vaccines, are always genetically modified vaccines, i.e. carrier virus vaccines. This has not yet been recognized by the regulatory authorities long enough for it to be safe. Fifteen years ago, there were still great reservations about this, and today, with the increasing success of these carrier virus vaccines, especially in this SARS2 pandemic, these carrier virus vaccines are already quite successful in clinical trials. In the case of Ebola, they have been very successful. And now that more such good experiences are being made, it is to be hoped that more nasal spray vaccines will soon be available. And of course, this is then possibly also as an entry into a cold vaccination in the future. With the many cold viruses that we have, more than 15 viruses that can be listed, we may at some point come to a situation where we have nasal spray vaccines against almost all of them, especially for the adult population. So I think it is not unwise for the children to go through these harmless infections for certain immunological reasons. But for the adults these infections are in some cases anything but harmless. One has to imagine for the economy how many days of sick leave in an economy are caused by the whole bouquet of cold viruses every year. If one could vaccinate against them, that would be an incredible success.”
Cool! Thanks!