Answers to Questions About COVID-19 Vaccines

What questions do you have about the COVID-19 vaccines? In our Facebook Live event, we got answers from Jared Eddy, MD, infectious disease expert and the director of Infection Prevention at National Jewish Health in Denver.


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Molly Casey: Good afternoon. My name is Molly Casey, and we are on live on the National Jewish Health Facebook page. Today will we will be interviewing Dr. Jared Eddy, an infectious disease specialist here at National Jewish Health, about the COVID-19 vaccines. Welcome Dr. Eddy.

Jared Eddy, MD: Thank you.

Molly Casey: So we're just going to go ahead and jump right in. There has been a lot of discussion about the COVID-19 vaccines and there's a lot of questions about it. So really the first question is, is does the COVID-19 vaccine work? You can speak to the different versions of the COVID-19 vaccine or kind of do a blanket answer, whichever you prefer.

Jared Eddy, MD: Well, it seems like the COVID-19 vaccines, and there are multiple ones of them at this point, are actually quite effective. If you think about what your usual flu shot is able to achieve, it's about 40 to 50% effectiveness because it has to be tailored to whatever strains are circulating. But with the first round of the COVID vaccines, which are the mRNA vaccines, they looked like they were about 95% effective in preventing disease of COVID-19, which is very high indeed. The second round of vaccines tend to have numbers for effectiveness that are a little bit lower, something more like 70%, for example. It also depends on whether you're talking about just simply preventing all disease or preventing really severe disease.

Jared Eddy, MD: And so the second round of vaccines were evaluated in a different environment when there was a lot more infection going around, and also we had to deal with these variants for which there has been some decreased effectiveness. However, the important point is that all these vaccines are very good at preventing severe disease, which most of the time means hospitalization and death. So none of these vaccines showed, in the vaccine group in the trials, anyone being hospitalized or dying after having COVID-19.

Molly Casey: That's really impressive. Another really big question is, are the COVID-19 vaccines safe?

Jared Eddy, MD: So if you're looking for a one-word answer, yes, they are actually very safe. There was a CDC periodical, or what we call the MMWR report, that came out a few weeks ago and it looked at Moderna and Pfizer vaccine, which were the first ones being given. And they evaluated data from about, I think it was 14 million people, and there is a vaccine reporting system. It's a passive system. So that means that it relies on you to report. So they reported about 7,000 cases. So that's a 0.05%. So that's only five people out of 10,000 people would have reported a side effect to the vaccine. So very small. Again, most of the mild side effects will not be reported, but you would think that more of the serious ones would be, and there are very few events that were serious vaccine side effects. And when they did find deaths and were able to do autopsy reports, they did not think that it was related to the vaccine because a lot of these vaccines, of course, are being given and very old people in nursing homes who already have heart disease and so forth.

Molly Casey: Interesting. So speaking of different reporting systems in that realm of things, what's the difference between being FDA approved and emergency use authorization?

Jared Eddy, MD: So FDA approval and our FDA, our organizational body, is one of the most stringent in the world and very highly respected for that because it's really evidence-based. And we also want to have enough evidence to make really good decisions. And that generally requires at least six months of safety data. And it takes a while to get there, but when you're in a pandemic and when there is a real need to have vaccines quickly to stop the pandemic and prevent further deaths and further spread, and you do not have any approved vaccines or easily acquirable ones, then the FDA does relax the ability to get new products out to people. And that's what an emergency use authorization does. It's still based off of data and they weigh the pros and cons of releasing something to the public without having the full approval. Essentially an emergency use authorization is a quicker way of getting good products to people.

Molly Casey: Interesting. So if somebody has already had COVID-19, should they still get the COVID-19 vaccine?

Jared Eddy, MD: So they should. And the reason is, is that we believe that your what we call natural immunity... that's the immunity you get not from a vaccine, but when you've been infected with the actual virus... it does wane over time. And so there's some pieces of evidence that play into that. So looking at other coronaviruses, we know that you can be infected with them again in a subsequent year. For people who have very mild infection with COVID-19, they don't seem to have too strong of an immune response sometimes, and we know that re-infection cases occur. So for all those reasons, you should look to get a vaccine for more durable, long-lasting immunity, even after you've had COVID-19 yourself.

Molly Casey: After a person gets the COVID-19 vaccine, how long does it take before you're protected from COVID-19?

Jared Eddy, MD: Well, the general answer for this is two weeks after you've completed a vaccine series. That's kind of the one answer you want to keep in mind. For some of the vaccines that are two doses, you do have some protection after the first dose, and that's being evaluated ongoing for vaccines like the Pfizer vaccine, but it is still recommended to get both your doses and you do want to have two weeks go by after that second dose, if you're having the Pfizer and Moderna vaccines.

Molly Casey: So if somebody gets the first dose of the COVID-19 vaccine and then gets COVID in between their first and second, should they still get their second dose of the vaccine? And if so, how long should they wait?

Jared Eddy, MD: So I think they should get the second dose. The guidance says that when you're in your infectious period... for most people, that's 10 days, for some people it's up to 20 days... you should not get your second dose during that time. Once you're after that period, you can get your second dose. But the CDC does say is that most people are going to be protected from natural immunity, plus you've already had a first dose. And we think that will last you in most cases three months. So as kind of an altruistic measure, you can delay your second vaccination for three months to allow others to get it in that period of time. I generally think that the milder case of COVID-19 you have the more you'd be thinking about getting your second dose more quickly. If you had a more severe reaction, then you can probably push things out a bit longer.

Molly Casey: Okay. If someone has already gotten the COVID-19 vaccine, do they need to get the flu shot, or if they've gotten the flu shot, do they need to get the COVID-19 vaccine? Are there differences?

Jared Eddy, MD: So different viruses, different diseases, different shots. So you should get your flu shot and you should get vaccinated against COVID-19. And the important thing is that if you are going to get another vaccine along with COVID-19, you do need to space them out by at least two weeks.

Molly Casey: Okay. So how do you know when you're eligible for the COVID-19 vaccine? It's sometimes confusing for people.

Jared Eddy, MD: Well, it's very confusing actually, because every state has a different system for determining who should get COVID-19 vaccine and which phases. There's a lot of subtle differences between states and also within Colorado, the phases have changed a number of times themselves. I commiserate with people for having trouble with this, but I would say that the state has a very good web page, and I would encourage people to go there to learn about where you can be vaccinated and what the prioritization groups are and where we are in that process right now.

Jared Eddy, MD: And for places like National Jewish, we are reaching out to patients to notify them that they are in a group that would be eligible for a vaccine and trying to bring people in to get vaccinated. So you could have someone reach out to you if you're plugged into your healthcare group, or I would encourage people to take the initiative and go online and figure that out, too.

Molly Casey: Perfect. Is it possible to contract COVID-19 from the vaccine?

Jared Eddy, MD: So that is not possible, and it's not possible because these are not live vaccines. Essentially what these vaccines are, is they are delivering into your body a means of producing the spike protein, which is the most important part probably of the virus which allows it to enter cells, and it's also what your immune system reacts to. So you are not creating a virus with the vaccine. You're creating an immune reaction to a key part of the virus.

Molly Casey: Oh, interesting. Okay. Can you stop wearing your mask once you've gotten your COVID-19 vaccines?

Jared Eddy, MD: It's a very controversial topic. So the answer is in public, no, and this is a developing area of expertise right now. So just a few days ago, the CDC released information for the general public, that if you're indoors in a private space with others who have been vaccinated, you do not need to wear a mask. And if you are visiting a single household, and there's no one in that household who is vulnerable to severe disease from COVID-19, then you do not need to wear a mask, but for public considerations, you still do need to remain masked. And the important thing here is that we do know that in some cases people get vaccinated and then can still develop COVID-19. And we think that people can be infected with it, so they're carrying it, not potentially know that and still transmit it to others.

Jared Eddy, MD: Now, there is data coming out from some of the vaccines like Pfizer in places like Israel, where a lot of people have been vaccinated, suggesting that actually it's a pretty low percentage, but this is all very fresh and we really do need the guidance of the CDC to look at the data and to come up with more detailed consideration. So that is forthcoming. But for now, we want to emphasize that if you have been vaccinated, in public you do need to socially distance, wear masks and so forth. And that is quite important still.

Molly Casey: And just so you all know, CDC stands for the Centers for Disease Control and Prevention. So they're just some of the terms that describe the national organizations that oversee things like the response to the COVID pandemic. So those are kind of the big questions that we have for today. Do we have any questions from the audience?

Adam Dormuth: Dr. Eddy, would you please explain maybe some of the differences between the Moderna, Johnson & Johnson and Pfizer vaccines and is one preferable to the other for folks?

Jared Eddy, MD: So the Moderna and the Pfizer vaccines are mRNA vaccines. So what they do is they deliver into the cell using a fatty particle, the code, or the mRNA, for the spike protein to produce an immune reaction to it. The Johnson & Johnson vaccine, what it does is it takes the DNA, so a slightly different form of the code for the protein, and puts that inside of another virus, an adenovirus, which is something which causes the common cold. That adenovirus has been changed so it actually can't make you sick. But essentially what it is, it's a delivery mechanism that's different from the Pfizer and Moderna vaccines.

Molly Casey: Interesting.

Jared Eddy, MD: The important point about Johnson & Johnson vaccine is that it is a single dose, whereas the Moderna and Pfizer vaccines are two doses, either three weeks or four weeks apart.

Molly Casey: Interesting, okay. Looks like we have quite a list of questions actually on our table over here.

Adam Dormuth: Should you worry or have specific concerns about the different variants that are out there right now after you've been vaccinated?

Jared Eddy, MD: So the few variants that we are kind of focusing on in terms of vaccination... well, there are three main variants, I should say, internationally. There's the UK variant, which scientists believe will actually become dominant in the United States soon. Now the Pfizer vaccine works very well against the UK variant. And I think the other vaccines seem like they do, as well. That that's what the data suggests. And that's because that variant really has a mutation that allows it to be more transmissible, but it doesn't alter the structure of the spike protein.

Jared Eddy, MD: The Brazil and South African variants have a mutation that does alter the structure of the spike protein. And for that reason in test tube studies, the vaccines have not been able to neutralize the virus as well, but they still do neutralize the virus. So how do you interpret that clinically? Basically it means that you might get COVID-19 after having exposure to the South African or Brazil variants, but again, you're still going to have protection and you're not going to be hospitalized or die. So it still makes sense to be vaccinated, even with concerns for these Brazilian and South African variants. And those are the variants that are still less common in the United States, although we are really ramping up our ability to detect these with the money from the latest COVID bill.

Molly Casey: Interesting. Okay.

Adam Dormuth: Will we need a yearly COVID vaccine, much like the flu shot?

Jared Eddy, MD: Maybe. I think it's quite likely that we could see boosters. So there's two reasons which you may need to have COVID vaccination more than once. So the first we were just talking about variants. The first is the drug companies are fine tuning their technology to make a vaccine that alters the code to more closely resemble the variants so that you have better protection against the variants. And again, you will have good protection in terms of severe disease against the variants right now, but they're making it even better so that you potentially don't get infected with a mild infection. That's one reason.

Jared Eddy, MD: The second reason is that idea of your immunity waning over time. So we don't really know how long the vaccine protection lasts yet, because this is new and the studies are ongoing. It looks very good at three months. There is some data from the UK suggesting at eight and nine months is good. Will it make it to a year or will we need another vaccine? I think that's still to be determined and it's quite possible.

Molly Casey: Okay.

Adam Dormuth: Will you explain the term long hauler in terms of those folks that are considered COVID long haulers, and then along with that, will getting the vaccine help or potentially help with some of those symptoms that those folks are suffering?

Jared Eddy, MD: So a long haul or post-COVID syndrome means essentially that you have a number of potential side effects from having COVID that are not really so much the cough and upper respiratory tract, symptoms of acute infection, but more brain fog or lingering myalgias. And so this happens in a smaller subset of people. Typically happens weeks after you have COVID-19 and it can last for months. So vaccination is not therapeutic. So you get vaccinated to prevent yourself from getting COVID-19, not to treat any symptoms of COVID-19. So I suppose it's possible that we might have some sort of therapeutic vaccine in the future, but that's not what vaccines are being used for right now.

Adam Dormuth: How's the determination made, and I realize that in a lot of cases it's a state to state determination, but the determination as far as who's more high risk and how they determine the eligibility tiers for vaccinations?

Jared Eddy, MD: So there are several considerations I think that go into who gets priority. The first people we wanted to cover were people in healthcare who are working with COVID quite often, and also the most vulnerable patients in long-term care facilities. There also is consideration of people who for their jobs need to be on the frontline and cannot really socially distance. If you're in a meat packing plant, for instance. In terms of individuals who may have medical conditions, the CDC keeps track of the data for who seems to be more likely to get severe COVID, based off of what medical conditions they may have.

Jared Eddy, MD: There is a webpage you can go to for this, and they have basically two levels and there's the strongest data. And then there is conditions for which there is less data. And so right now in Colorado, the recommendations are going with the conditions for which there's the strongest data to show you are at more risk of having severe COVID-19.

Molly Casey: Interesting.

Adam Dormuth: For those that have concerns around anaphylaxis or reactions to previous vaccines, is there one of the three common vaccines out there now that it would be more preferential or safer for those folks?

Jared Eddy, MD: I don't think that's the case. I can tell you that with that CDC report that I was referencing before, there were something like four or five cases of anaphylaxis, very few. That is consistent with other vaccines, non-COVID vaccines, and consistent with what you would expect just in the general population that's not being vaccinated. So anaphylaxis is still very rare with the mRNA vaccines, and to my knowledge, also with Johnson & Johnson.

Adam Dormuth: For those folks that have the concern of anaphylaxis, then would it be more advantageous that they try to get their vaccination in a hospital setting as opposed to a drive-through clinic? Or is that really not...

Jared Eddy, MD: Well, depends on what you have a history of allergic reaction to. So if you know that you've had allergic reaction to one of the vaccine components, then you don't get it. If you have some sort of a severe allergic reaction to a first dose, you do not get the second dose. So those are the absolute contraindications. Then if you have a history of allergy to some sort of injected medicine, so not an oral medicine, not a tree or a nut, but actually an injectable medication, then that's a precaution, and basically you are watched a little bit longer when you get the COVID vaccine. And you should be in a setting where someone can give you epinephrine or respond to an anaphylactic reaction if it occurs, and most sites where you get vaccinated do have that ability to address that should it happen.

Adam Dormuth: Should folks still be weighing when they come in for medical testing based on whether or not they've been vaccinated or not? So for example, someone that is scheduled for a overnight sleep test, for example, but has not been vaccinated, should they be concerned with the fact that they've yet to be vaccinated?

Jared Eddy, MD: Well, for the example that you give, that's a pretty low risk situation because you're with a technician who's been vaccinated at this point and not around others and it's at night. So I think there could be some additional risk to going out in public. There is some additional risk to going out in public when you haven't been vaccinated. But we have been taking a lot of precautions throughout the pandemic in trying to keep our numbers pretty low.

Adam Dormuth: There've been some instances of folks that received the first dose, test positive for COVID in between the two doses. Do they keep that second dose appointment? How do they handle possible exposure or positive tested between doses?

Jared Eddy, MD: So I think we talked about that a little bit before, but essentially if you get sick with COVID, it depends where you are between doses, but you probably will have to delay that second dose because you're going to be infectious for 10 days. And so there's the idea of maybe you have two different immune responses at that point, but really you also want to protect the people that are vaccinating you. You don't want to get them sick. You're supposed to be away from them in that period of time. And then again you can delay that second dose up to three months after that period of time. There's no rush to get your second dose at that point.

Molly Casey: All right. Well, thank you so much again for being here today. If you all have any more questions to ask, once this is posted, feel free to post your questions below the video and we will try to answer as many of the questions that are posted as possible. So that is all for today. Thank you again.

Jared Eddy, MD: You're welcome.

Molly Casey: Stay safe everyone that's in Colorado this weekend as the snow comes in.

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