COVID-19 Vaccination and Celiac Disease
Happy holidays from the Center for Celiac Research and Treatment. I'm Susie Flaherty, communications director for the center and we have Dr. Alessio Fasano with us today to answer questions on COVID-19 and the vaccine. In the first part of this video,
Dr. Fasano will present the scientific facts behind the new technology in the mRNA vaccines to fight COVID-19. In the second part, he addresses questions that have come in from our social media platforms and other avenues with concerned patients and others. Good day everybody. At the Center for Celiac Research and Treatment at Massachusetts General Hospital, we've been receiving a lot of questions concerning the COVID-19 vaccines that the FDA authorized for emergency use in the past few days. I believe that there are a lot of questions that are really stemming from a lot of confusion about these vaccines-- what exactly they mean, who is entitled to take the vaccines, their efficacy and so on and so forth. So
before I really go through the questions that we received, I want to make a few clarifications about these vaccines. So far, we have two vaccines that have been authorized for emergency use by the FDA. One from Pfizer BioNTech and the other one from Moderna. And two more will probably be authorized at the end of January 2021. So I have to say that these are extraordinary circumstances and these two are extraordinary vaccines, because these vaccines really apply technologies that are almost a decade old but have never been deployed in humans before in such a short period of time. So they are really one of a kind and I want to say that in an ideal world a good vaccine is something that you can deliver in a single shot at room temperature that can really cover a lot of people and will protect for a longer time, even forever. But
these are not ideal circumstances and there are no vaccines that fulfill all these criteria. So let's start by saying, first of all, about these two vaccines-- what are their characteristics, what is their bottom line efficacy and safety (that is something that is in the mind of everybody) and then we'll go through the questions that we received. First of all, because of the number of doses that we have available and because of the timing of the vaccination, the target population right now is the population that is at risk: healthcare professionals, elderlies and so on and so forth. Because for a herd coverage we really need to vaccinate at least 75 percent of the population. And I will explain why we are not there quite yet. The Pfizer vaccine has been tested for people age 16 and older, while the Moderna is being tested and approved for people 18 and older. So a good part of the
pediatric population is not involved and approved for the use of these vaccines. They are based on a brand new technology, as I was telling you, that is what is called the messenger RNA. In general, vaccines are made by the microorganisms (in this case the virus) that can be killed or attenuated, as we use for polio or measles vaccines, so that the entire bug is injected in the host and this will instigate the immune system to build an immune response against this enemy and therefore we develop protection against that. Here is a very different story. Here, both these vaccines use this technology called messenger RNA vaccines. These are vaccines in which genetic information, that is this messenger RNA, coming from the virus that will translate in a product (in this case the protein is called spike) that is necessary for the vaccine to bind to the target cell and start to reproduce itself and spread is the target component of the SARS-CoV-2 virus. So what happens is that they are injected as messenger RNA in a
vehicle (little lipid droplets) that are called nanoparticles that will protect the messenger RNA against destruction from the host. And here is another major difference between the two vaccines. These droplets have been developed with much more accuracy (because they have more time) by the Moderna company. So there is no need to maintain, for stability, these vaccines in extremely cold conditions as with the Pfizer vaccine that has droplets that are less efficacious in protecting the messenger RNA. So that's the reason why the Pfizer vaccine [requires extreme cold for storage] while a regular refrigerator is okay for the Moderna vaccine. In both vaccines, once this messenger RNA is injected it will be eventually picked up by cells of the host that use their own machinery to translate this messenger RNA into the product (in this case the spike) that is seen as something that doesn't belong to our body and therefore instigates an immune response.
Both vaccines have turned out to be extremely efficacious, way beyond our most optimistic expectation. For an emergency use authorization the FDA requires at least 50 percent of efficacy. And as you've heard, both these vaccines go way above 90 percent efficacy in preventing COVID-19 in subjects that have been injected by these vaccines. The vaccines seem to be a little bit less efficacious in people 65 and older, mainly because the immune system in the younger folks is more crisp in mounting an immune response.
Both vaccines seem to reduce the risk of severe COVID-19 disease, but we don't know yet if they also prevent asymptomatic infections with SARS-CoV-2 virus. It's too early to say. Both vaccines require two doses: a priming dose, or a first dose, followed by a booster. The interval is a month (28 days) for Moderna and three weeks for the Pfizer vaccine. Both of them have shown some side effects and these have been raising concerns in a lot of people who have been reading about these vaccines. But in terms of vaccinology, a good vaccine should typically
show some reactions that are actually signs that the immune system sees an enemy and is mounting an immune response. And indeed both vaccines fall into this reactogenic category of vaccines. So the most common side effects are pain at the site of injection, fatigue, headache, some muscle pain and joint pain. A few have reported fever. And again, these are symptoms that are more common after the second dose that are signs that the immune system is really kicking into gear to start to build an immune response and is exactly what we want to achieve. However, the reactions that have been raising the concerns have been this allergic reaction to the Pfizer vaccine. These reactions, and some are very severe to what we call anaphylaxis (a severe allergic reaction), were not seen in the clinical trial, but were severe enough to require hospitalization of the people that received the vaccine. All these people --actually two, three cases-- were people with a history of severe allergic reaction and they both carry the EpiPen because of their history (an injection of adrenaline in case they have a severe reaction).
So we've discussed about the storage requirements and the reason why there is a difference between these two vaccines. [Let's talk about] what we don't know yet. We don't know the duration of protection. Again, these are vaccines that have been tested relatively early. These are the first messenger RNA vaccines that are being deployed in clinical trials at such a large scale and therefore we are in uncharted territory here in terms of if this vaccine will protect for a short period of time or a long period of time or forever.
That's something that we will learn on the go. And we will watch the reports that people have been immunized and when the numbers get large enough to understand what's going on. So all in all, I think that I can say with a great level of confidence that this vaccine seems to be extremely safe, extremely well tolerated, extremely efficacious in what we've seen so far.
There's a lot we don't know yet, but the reactions to the vaccine are the ones expected when you use something that mounts an immune response. The severe side effects are allergic reactions that've been seen only in people with history of severe allergies and therefore are not generalizable. And finally, because of what I discussed at the very beginning, the limited supply of these doses hopefully will increase over time.
And because this vaccine has never been tested in a pediatric population, right now the goal is NOT to reach herd immunization so that everybody can be without the mask and just relax with the physical distance and washing hands and so on and so forth. This will be a goal that will be reached only when we will have this vaccine tested in the pediatric population (and therefore they will be part of the people that will be vaccinated) and we have enough doses to vaccinate 70 percent of the population worldwide, because it's not just a matter of the United States. We're in a global village and therefore this can be achieved not only when you know nations can afford the vaccine, but when everybody will be able to have access to this vaccine to reach that level of protection. So this is the factual information that we have about these vaccines at this point. I think that we need to just have the patience and wait to see how eventually these unanswered questions in terms of the the few issues that I discussed (about durability of protection, particularly when we can really reach the herd protection) will be achieved. In the meantime,
let's keep our masks on. Let's keep our physical distance as a rule of living and of course continue hand hygiene. These are the three pillars that really have been able, when implemented, to really minimize the impact in terms of morbidity and mortality of this virus. Thank you Dr. Fasano. Now we will turn to questions that have come in about the vaccine from our social media platforms and other avenues. The first question-- Do any of the potential vaccines contain gluten? The answer's no. There is absolutely no gluten in these vaccines. There is no need to add gluten. As I told you, these vaccines are mainly made by genetic material from the SARS-CoV-2 virus along with lipid droplets that by definition don't contain gluten. Why is it that some people with
celiac disease do not respond to the hepatitis B vaccine or they require revaccination with the hepatitis B vaccine? The reason why the hepatitis B vaccine sometimes doesn't induce an immune response in celiac is not completely understood. But it looks like it has to do with the capability specifically of that vaccine against the hepatitis B, because that's not shared with other vaccines that we have available that are mandatory to be used. So it's probably due to the fact that this is something that is pertinent to the hepatitis B that is not inducing the immune response at the first vaccination. I have to say that the second boost, if we see low levels of hepatitis
B antibodies, in general is successful to mount a proper protective immune response. Is there a chance that people with celiac disease may not respond to the COVID-19 vaccine or might need to be re-vaccinated before it is effective? Again, this is related to the previous question and the answer is that we don't know yet because we don't have a critical number of people with autoimmunity in general, celiac disease specifically, who have been vaccinated to answer this question. But the expectation is that that's not the case, because this is a messenger RNA vaccine. When this messenger RNA is put in motion and starts to produce a large quantity of these spike proteins it will be just a matter of time before immune system will see this enemy and it will start to mount an immune response against it. So the capability to mount an immune response to
non-self proteins by celiac disease patients is comparable to the general population, so I would not anticipate anything like this. Can you tell us if there has been any consideration given to what vaccine candidate would be the best vaccine for people with celiac disease? Well in terms of safety and efficacy these two first two vaccines based on messenger RNA are equally effective and therefore I think they are interchangeable. If we get one or the other vaccine, they should work equally effectively so I don't think there's going to be a difference. There are many other vaccines in the making with different technologies, including to use other viruses like adenoviruses as a vector to deliver this spike protein or attenuated vaccines.
But also in those cases I don't think that there's going to be any difference in terms of how a person would see the disease and respond to one versus others. Which vaccine technology is most likely to activate an immune response, otherwise known as immunogenicity? Well I have to say these two messenger RNA vaccines that, again, it was a concept that was initiated almost 10 years ago at the University of Pennsylvania and never saw the lights of clinical application because of some technical hurdles in terms of the stability of messenger RNA, how to deliver this messenger RNA, how to protect against degradation because messenger RNA are very fragile when injected. All these real technical hurdles have been resolved in an astonishingly short period of time. And I have to say in terms of immunogenicity so far based on the number of people that have been vaccinated in the United Kingdom and now here, it seems to be quite effective in inducing an immune response. Of course,
only time will tell us in terms of the duration [of protection], which in my humble opinion is the major question mark of this vaccine. How long are they immunoprotected and that this protection will stand. And here is our last question. Dr. Fasano, how likely are the mRNA vaccines to be more or less effective than more standard vaccines? Well this is a good question to which we will have an answer when we can compare vis-a-vis the mRNA vaccine-based remedies for COVID-19 compared to more traditional vaccines with attenuated SARS-CoV-2 or vaccine vectors like adenovirus in which they carry these proteins from the SARS-CoV-2. We can't compare the past. First of all because we never had a messenger RNA based strategy and secondly because each different microorganism reacts differently when it comes to immune response so we have to wait when these other generation vaccines against the SARS-CoV-2 will become available and people will be vaccinated. So we will see if there is difference in terms of
effectiveness, particularly in terms of protective time against the vaccine. So this is the status of the arts concerning vaccination. Again, there is a brand new horizon that is opening with the event of these vaccines that were able to be deployed in such a short period of time. I think that this will change completely with landscape starting with protecting the ones that will be receiving the vaccines and then hopefully moving to the herd protection of the entire population. With that, I want to wish you all happy holidays. Stay safe, stay well. Thank you for joining Dr. Fasano and myself today. We wish you a safe, healthy and happy holiday season and new year.
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