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Podcast: Dr. John Zurlo on the COVID-19 Bivalent Booster, Monkeypox and Polio

Infectious diseases expert and chair of the Jefferson Enterprise COVID-19 Task Force brings us up to speed on the latest information on COVID, monkeypox and polio, plus, his thoughts on masking going into the flu season.

Infectious diseases expert Dr. John Zurlo joins The Health Nexus Podcast once again to provide the latest information on COVID-19, including how he would time getting the Omicron BA.5 bivalent vaccine and the flu shot if you’re trying to avoid feeling potentially crummy. Also on the docket of topics: masking recommendations this flu season, whether we’ll see a surge this fall/winter and much more on that new bivalent vaccine.

We also get an update on the monkeypox virus affecting our region and Dr. Zurlo breaks down the recent polio outbreak. A top recommendation? Be sure your vaccine records are up to date.


Is COVID-19 over? –  01:13
Is anyone still a COVID virgin? –  03:30
On bivalent COVID-19 vaccines – 04:18
Why you need the primary COVID vaccine –  05:10
Who is eligible for this booster? – 06:06
Was the bivalent booster tested on humans? – 06:35
What is the best time to get the booster? – 08:22
How long does immunity last? – 09:11
Do you need the booster if you already got the Omicron variant of COVID? – 10:03
Should we get the COVID booster and flu shot together? – 11:01
How long until immunity from the booster kicks in? –  11:46
Will we face a COVID surge this fall/winter? – 12:02
Tips on spacing out COVID booster and flu shot – 12:46
Should we be masking up this flu season? – 13:27

On Monkeypox

Update on outbreak affecting the region – 15:26
Who should receive the monkeypox vaccine? (And its side effects) – 18:15
Best ways to protect yourself and community – 19:43

On Polio

Dr. Zurlo on the recent polio outbreak and what caused it – 20:18
History of polio – 21:28
Getting the polio vaccine and if it’s harmful to get it twice – 24:32

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Complete Episode Transcription

Carly Williams: I can’t believe this is our third autumn since the COVID-19 pandemic started and many of us have getting the latest COVID booster on our list of to-dos. But how is this booster shot different from the other vaccines? And how long will immunity last after getting it? Welcome to the Health Nexus podcast, powered by Jefferson Health. I’m Carly Williams.

Jessica Lopez: And I am Jessica Lopez. We are back with more health questions for Jefferson Health experts to weigh in on and in this episode, we’re getting the latest information on COVID-19 from Dr. John Zurlo. And that’s not all. We’re also discussing monkeypox and polio, two infectious diseases that have unexpectedly also made recent headlines.

Williams: Our show notes mark when Dr. Zurlo discusses each of these topics. So feel free to check that out to quickly find the information you’re most interested in. That’s right. Let’s get into it. Here’s our conversation with Dr. Zurlo.

Dr. John Zurlo: Dr. John Zurlo. I’m a professor of medicine here in the Division of Infectious Diseases at Thomas Jefferson University Hospital where I serve as the director of the division. Also, I serve as the chair for the Jefferson Enterprise Covid Task Force

Lopez: President Biden stated in a recent “60 Minutes” interview that “the pandemic is over. If you notice, no one’s wearing a mask. Everybody seems to be in pretty good shape.” Since then, there’s been a bit of backlash that this statement is insensitive to those Americans still dying from covid and some public health officials also say it’s inaccurate.

Dr. Zurlo: I’d have to say that COVID certainly has changed, and I think the worst time we saw with COVID was really right in the beginning March through May or June of 2020. We saw lots of hospitalizations, but even more so the patients were really much sicker at that time and we had a very high mortality and we watched then as time went on with treatments with increasing immunity in the population with the widespread use of vaccines and boosters and so forth. We certainly have seen a reduction in the morbidity or the seriousness of covid and nobody would argue with that comment. Anecdotally what we see in our hospital, we do see still covid patients, but so many of them are incidentally diagnosed, just not as sick as they were back then, which is not to argue that there are not some already or still dying with severe covid.

Most of those are people older or with immunosuppression or multiple medical problems just like you read about. So that certainly is a part of the pandemic that’s still persisting, but it’s really quite different. It’s really has changed quite a bit and it’s a much more comfortable place we are now than where we were then. And certainly, much more comfortable than when we see saw that bad surge of these crown variant back in January and February of this past year.

So, in summary, then, is the pandemic over? I don’t think so. We’re not quite beyond that, but remember the population at large has a great deal of immunity and frankly, I don’t know anybody who hasn’t had covid and that certainly will provide some protection. But the protection that we know best is people who’ve been vaccinated and, and obviously many people have had the combination of both vaccines and natural covid and therefore we have quite a change in the degree of immunity in the population and that leads to a better situation. So we’re not done with it, but we’re in a much better position than we ever were, frankly.

Lopez: And if I can ask a follow up question, to your point, there’s not many people out there that have not had COVID yet. Do you think if anyone is a self-professed COVID virgin, is it safe to assume they probably did get at some point asymptomatically or do you think they may have actually dodged it somehow?

Dr. Zurlo: I think a combination of both of those things. Even in the worst of any pandemic, there are people who, for reasons we don’t fully understand, just seem to be, I’m going to say immune, but immune and maybe a lot of different ways, maybe they just haven’t had the exposure. Maybe they have something that we don’t understand that keeps them from getting sick and just as you point out, maybe have had truly asymptomatic infection. So they’ve had a great immune response and didn’t get sick from it. And indeed we might find out if tested that they were in fact covid positive at one time.

Lopez: New COVID boosters for Omicron BA.5 are officially out. This vaccine is a bivalent vaccine. Can you explain what that means?

Dr. Zurlo: Since the onset of the Omicron variant that was first recognized in South Africa in November of 2021 and spread like wildfire throughout the world, we’ve seen now Omicron variants have really taken over in every part that there’s BA.2 and BA.2 and three and four and five and so forth. And the boosters are designed on the one hand to still retain some element of the initial vaccine that we once gave starting in December of 2020. But also, they’ve been updated that the other half of the vaccine now is really targeted to these Omicron variants. So we believe that this will lead to better protection against really all forms of covid.

Williams: Why do you need the primary covid shots before you get the booster?

Dr. Zurlo: I think the reasoning is really largely due to the fact that we have good data to know that if you’ve had the primary shots—or in the case of Johnson and Johnson, one primary shot—that really alone has provided significant protection against serious illness from COVID, and we were able to test those before those vaccines came out. So we know that those work in the real clinical realm. And right now the boosters only contain a small or half of the dose of that original vaccine. We don’t know that half would provide enough overall coverage and immunity to offer that same level of protection. Just as a precaution, we still believe that if you’ve not been vaccinated, you really should get the initial vaccine first. Because we know in the real world that works and now with the booster, we think that will provide added protection.

Williams: And if you could just explain who is eligible for the booster and if children are?

Dr. Zurlo: The new boosters have been approved both for the Moderna and Pfizer. Pfizer is approved for individuals 12 years of age and older. The Moderna is 18 years of age and older. So since they are intermatchable, if a child has been vaccinated with Moderna for example, they can still get the Pfizer booster. It’s just a matter of how they’ve been tested and approved in the clinical trials.

Lopez: We recently posted about the new booster on our Jefferson Health TikTok account and received a question in the comments about why this booster was not tested on humans.

Dr. Zurlo: No, it has been tested on humans. What we don’t know about it is unlike the original vaccines, both Pfizer and Moderna that we tested in the real world, we looked at the endpoints were, you know, you’ve been vaccinated, how effective is vaccination in preventing COVID? And moreover, the serious consequences of COVID? And we learned that they were quite effective quite frankly. And then of course all these variants came about and there’s waning immunity, all of which prompted us to then develop this booster strategy. And so we have tested these vaccines and we have at least immunologic data. We measure antibodies in the immune response to the vaccines as a surrogate, as a measure of protection, rather than having to wait many months to what may be a COVID season to determine if they really work in the real world. And this is not unusual. Every year we design flu vaccines based on what we think the new strains are apt to be in the future. And in essence, on an act of faith that will translate into immunity and ultimately protection against influenza. And sometimes we get it really right and sometimes we get it not so right at all.

Lopez: Are there any side effects that are unique with this booster that we didn’t see with the others?

Dr. Zurlo: Not that I’m aware of. And of course, we’re just starting this, but I think we’d expect the same kinds of things, the local reaction sites at the vaccine site and so forth, fevers, malaise, chills, that kind of thing over the first 24 hours or so. I don’t think we would expect to seem much difference in that frankly. And these very rare side effects that we see.

Williams: And there’s a lot of questions on the best time to get this booster. Do you have any insight if you’re trying to time it right with the holidays, when people might be having more exposure for example?

Dr. Zurlo: That’s a hard one to answer. We do recommend that that people wait at least two months from the most recent shot that they’ve had, whether it be the primary series or the booster. That’s for sure. If you’ve had COVID, it’s not a hard recommendation, but you might want to wait around three months from the time you’ve had COVID to get the booster. But beyond that, I don’t know. I’m not sure that there’s any good timing because, after all, we’re not going to know how long the effectiveness of the boosters will be. I would say really when, when anybody can get it sometime in the fall, especially those individuals at high risk for the serious complications of COVID should most certainly get it any time now as far as I’m concerned.

Williams: And you already kind of hinted at this, but is there a definitive answer on how long this booster provides immunity for?

Dr. Zurlo: We really don’t know. Remember, the two things we don’t know is, number one, how effective will the booster be in preventing symptomatic or even asymptomatic COVID infection? Initially the two dose vaccines seem to be very effective in preventing symptomatic infection, but somehow that effectiveness waned in the sense that, whether it because of variance or just waning immunity—I don’t know—people could still get covid even with two doses of vaccine, but they weren’t getting sick from it, seriously ill, dramatically reduced that. So, will the booster provide protection against just infection, even cold symptoms? Don’t know exactly. Will it help prevent against the serious complications? I think we believe so.

Lopez: This is another question from our TikTok post. Do you need this booster if you already had the Omicron variant of covid?

Dr. Zurlo: Yeah, that’s a great question. In general, it goes back to the question of if you’ve had COVID, what’s the sense of vaccination? Here are the challenges, there’s COVID and then there’s COVID. For people who have had maybe very mild COVID or even asymptomatic COVID, we can’t easily measure how robust the immune response is in comparison, for example, to somebody who has had serious COVID. What we do know is when you standardize at all with vaccination, we know we have measurable results from vaccination that are not possible from people who’ve had natural COVID. So, the answer is, if you’ve had COVID, great, will it likely provide you some additional benefit? Sure. I bet you that’s true. But we just can’t quantitate that and therefore we would recommend that people get the booster.

Lopez: And something that a lot of colleagues and friends have been sharing anecdotally is to avoid getting the flu shot and booster together because of how crummy they’re feeling afterwards. Is getting these shots together something you recommend?

Dr. Zurlo: The CDC officially said, you can get them both at the same time, one in one arm, one in the other arm, maybe both in one arm. I think it’s just a matter of your personal preference. I think if you’ve had a serious side effect, beyond that, not a serious side effect, you really were taken down for 24, maybe 48 hours after one of the shots, particularly the COVID shot, it may suffice just to spread them out, rather than risk the double whammy of side effects from both. But there’s no clear guidance or indication that’s a dangerous thing to do.

Williams: And will it take two weeks after you receive the booster to gain that protection?

Dr. Zurlo: It’s a general statement of vaccination. We think around two weeks is the time it would take the immune response to really fully develop and provide immunity, so, I would assume so.

Williams: And with the third autumn of the pandemic just starting, do you think we could face another COVID surge?

Dr. Zurlo: We could face an increase in cases over the winter, but I don’t think to the degree that we saw with Omicron. We saw surges, if you remember back and as we walk through the timeline of COVID, the original strains that occurred at the start of the pandemic and then by the next summer we had Delta, and that seemed to be quite contagious and serious. And then, of course, Omicron came around and seemed to change everything. Remember there’s just wide immunity in the population at large and if we’re going to see a major surge, I don’t think it’s going to be the kind of surge that’s going to hospitalize a lot of people in the way that it did in the past. That’s my assumption.

Lopez: I have a follow-up question. For the folks who do want to space out their flu shot and booster to avoid any potential crumminess, how long should they be waiting in between those shots? And do you have any recommendations, if you are doing that, which one you should be receiving first?

Dr. Zurlo: It’s going to be difficult to predict the flu season, so when we did have flu <laugh> before COVID, there were a lot of flu cases. The flu season tended to be after the first of the year, but it’s really unpredictable. So, my take would be if I were moving along in this way for myself, I’d probably get the COVID vaccine first, followed by the flu shot, either simultaneously or a few weeks apart. That’s what I would do.

Lopez: And now where do you see masking during the flu season? In past interviews you’ve pointed out that flu cases have gone down since the pandemic started and thought in part that could have been because of all the masking. So now that people aren’t masking as much anymore, do you think that could work against us when it comes to the flu?

Dr. Zurlo: I do think masks have reduced not only flu influenza in the last few years, but lots of respiratory viruses, and there’s lots of data to support that. And why would that have been the case? We haven’t been as connected. We’ve been socially isolated rather severely at first and I think widespread mask-wearing all have something to do with it. With that said, I don’t think the public has much appetite anymore for masking. So actually I should separate that. In the healthcare setting, we will be masking healthcare workers in the healthcare setting. We will be masking for the foreseeable future. Not sure what the signal will be that we’ll say doctors and healthcare professionals no longer have to mask in the healthcare setting in the public and in public spaces. I think that’s going to be very difficult to guide people about that. I think mask mandates would take some pretty extraordinary change in transmission of any respiratory virus to go back to mask mandates, at least in the United States. I think individuals vaccinated or not who are in what we call high risk situations—so immunocompromised individuals, people who are older, especially 65 and older people who have a lot of medical problems, heart disease, kidney disease, liver disease, diabetes—they should seriously consider their risk as the cold, flu and potentially COVID season comes about. And then over the next few months, really strongly consider their risk and consider wearing masks in those public spaces.

Williams: As of September 19th, Philadelphia has had a total of 446 cases of monkey packs. New Jersey has had 661. Can you please give us an update on the outbreak affecting our region?

Dr. Zurlo: Well we, as you’ve seen probably also in the data, both in the world, in the country and certainly in the Philadelphia area, we’re seeing a decline in cases. In fact, I was on a call just today with the Philadelphia Department of Public Health about our monkeypox response. And so we’re observing this throughout the city that the numbers of cases are falling. And that’s a good thing. That’d be hard discussion if now, if the cases were continuing to arise despite our efforts to contain it.

Williams: Is there any possibility for a surge?

Dr. Zurlo: I’m just guessing that the surge that we’ve seen is probably as bad as it’s going to get. Probably because the really, the focus is on, it has been on really just a specific population. It has not spread beyond largely the MSM populations throughout the country. It’s really not spread to healthcare workers, for example. It’s not spread wider in the community. And I think for a lot of the MSM community, I think there’s a lot of behavioral change—many have become vaccinated, those who have had monkeypox now probably have developed some immunity—a combination of all of those things would suggest to me that the population at risk will be relatively limited.

Lopez: There is a high demand for the vaccine, but a severe reported shortage, the FDA and CDC determined by scientific review that it is safe and effective to give a lower dose of the vaccine intradermally. Can you explain exactly what that means?

Dr. Zurlo: The vaccine is originally licensed to be given as a vaccination subcutaneously. In other words, there’s a needle that pierces the skin. So it goes beneath the skin, up above the muscle, and that’s where the vaccine is deposited. Now it turns out, if you curve the needle and actually infiltrate it right within the skin, it’s a little painful, quite frankly, and it’s a way we’ve been doing skin testing for tuberculosis for decades, but the skin has specific immune cells in it that react to vaccination and immunization. And these particular cells that reside within the skin, but not necessarily in the subcutaneous tissue, seem to be more reactive and result in the fact that we can give a smaller dose of the very same vaccine and achieve similar levels of at least measured immunity as we determine with antibody titers and so forth. So we have admittedly limited data, but the data would suggest that the immune response between subcutaneous and a much smaller dose of intradermal are equivalent.

Lopez: And considering the limited supply of this vaccine, who do you strongly recommend get it preventatively?

Dr. Zurlo: We’re really targeting the population at highest risk, which is generally men who have sex with men, MSM, because they seem to be the population at highest risk—and especially those who’ve had contact with individuals who’ve been diagnosed with monkeypox or have had anonymous sex partners. And so I think as a broad statement, those are the individuals that we’re focusing most highly on. I would add to that in addition to those who’ve had any of the above plus or recently diagnosed sexually transmitted infection. So it’s that population that seems to be so far at highest risk for transmission and infection and therefore they’re the ones that we’re targeting most in in that regard.

As of today, the Philadelphia Department of Public Health suggests that we do have a reasonably good supply vaccine given this way in the reduced dose intradermally to complete the vaccine series. Remember, it’s a first dose at time zero, and then four weeks later we give a second dose and we think that’s the most effective immune inducing regimen of vaccination.

Williams: And are there any side effects that people should be aware of?

Dr. Zurlo: I think the side effects have been generally pretty mild as always—pain, redness, inflammation at the injection site, particularly when given intradermally, some people get fevers and chills and malaise over the first 24 hours…very few serious reactions, quite frankly, happily so far.

Williams: If you aren’t getting the vaccine, what are the best ways to protect yourself and community?

Dr. Zurlo: I think that the intimate contact often associated with sexual contact, but not always, is probably, it seems to be the highest risk overall. And I think the reason we’re seeing decreases in the incidents now throughout the world, country and the Philadelphia area has almost certainly be in part due to changes in these sexual behaviors and intimate contact behaviors. So I think clearly changing that behavior, reducing those contacts is going to be very helpful.

Lopez: Polio was found in New York City’s wastewater in late August, sending many people into a spiral to figure out what exactly polio is, how serious the outbreak is and could be. And trying to figure out if they got the polio vaccine at one time in their life. How concerned are you about this outbreak and what caused it?

Dr. Zurlo: I’m concerned just insofar as we’ve been working hard over the last few decades to truly eliminate polio from the entire world—there’s been a massive vaccine campaign through the WHO and and other organizations, like the Rotary Club, for example—to really try and eliminate. So it’s been within our grasp for a long time and there have been various impediments that have prevented that, quite frankly. The outbreak that occurred…I think there’s just been one case of flaccid paralysis in a fellow from Rockland County, and they’ve identified him as a young adult who had been unvaccinated and the strain that he acquired was probably from vaccine strain, although we can’t trace that.

Let me give you the polio vaccine 101 talk. The original vaccines that were developed by Salk and Sabin back in the early 1950s, included an injectable form, which is not live virus but inactivated virus, but again, it’s injectable. And the other was the oral polio, which I got as a child, which is a sweet tasting combination of the three principle circulating viruses, oral polio virus, one, two and three.

The oral polio vaccine, because it’s oral is so much easier to administer throughout the world in places that are resource poor and that’s been used for a long time until relatively recently, it’s no longer used because of this fact. One of the strains of the attenuated oral polio vaccine oral OPV2 can occasionally revert back to an infectious form and cause the disease we call polio, the flaccid paralysis. I understand that this gentleman was infected with that particular viral strain that probably came somewhere from somebody who was vaccinated overseas. So, I know that’s a long-winded explanation, but we don’t really understand how this happened, but we do understand is that this gentleman was unvaccinated.

Most of the country has been vaccinated and really for the last 20 or more years the only vaccine that we give now in the United States is the so-called IPV inactivated poliovirus, which is given in intramuscular vaccine to children. And we think that the population at large in the United States is largely protected but not completely protected. We do think that the immunity from childhood vaccination is very long lasting, so, I don’t think anybody’s suggesting that we start massive boosting of the entire population right now. So it remains to be seen. Now wastewater has become a really interesting and excellent way to follow certain kinds of infectious pandemics and we have followed it and continue to follow it with COVID and we can follow it in in polio and other infectious diseases and it gives us some kind of insight into what may be circulating in the community.

I’ll make one other observation. For all of us who’ve been vaccinated, we could still acquire polio in ways typically what we call the fecal oral route—eating contaminated food or something that has polio—and it will prevent us from getting the flaccid paralysis, which is, of course, what we’re trying to do in preventing the disease we call polio, but we can still transmit it actually. So the fact that it’s circulating, even among a population that’s been highly vaccinated, it suggests that, you know, it has been a bit more widespread than just one individual. So that’s the concern that I think people have.

Lopez: Do you suggest people find out when they receive the polio vaccine and getting one if they didn’t? And is that something you can just talk to your primary care doctor about receiving?

Dr. Zurlo: Sure. You most certainly can. If you can find out whether you’ve been vaccinated, if you’ve not been vaccinated, I strongly encourage it to get vaccinated. If you’re an adult—sometimes for people who are older, they may have no access to the records about their polio vaccination—so sometimes that might be very difficult, frankly.

Williams: Is it harmful to get it twice?

Dr. Zurlo: No. In fact, I got a vaccination, a booster vaccination, as we sometimes do in traveling to certain parts of the world. So right now, I think the guidance is if you travel to Afghanistan or the most worrisome places Pakistan, then it’s advised and if you’re going to be there for a long time, it’s advised that you get a booster vaccine just in case, just because of there’s more circulating virus there. Also, for individuals who care for people who might have polio, for example, healthcare workers and a few others, it is suggested that they consider getting a booster vaccine. So, I’ve gotten a booster many years ago when I traveled, and there’s really no, no problem or contraindication to it.

Lopez: COVID, monkeypox and now polio. It seems like anymore, anytime you check the news, there’s a new infectious disease we need to protect ourselves from. Are these truly unprecedented times or has covid just raised our collective awareness about these diseases and so the media, and so we, are more tuned into these updates?

Dr. Zurlo: I think there’s a lot to what you just said about media. Let’s face it, media is so pervasive. Within 20 minutes, if somebody’s been killed in some kind of accident or something 2000 miles away, compared to waiting for the paper the next day or the next week, so there’s certainly an element of that.

And I’ll say that let’s face it, epidemics and pandemics have been part of the human experience for as long as we can remember. Just in my career when I started in infectious diseases, I’ve been through HIV and AIDS. That took up a great deal of attention for a lot of people, including mine, followed by a lot of near misses. If you think about SARS in the early 2000s, then there was the H1N1 flu in 2009 and there was MERS, which had a very high mortality, and that just seemed to peter out. And then we had Zika. That was a huge scare for the world. Then leading up to COVID, monkeypox and now polio. So, I think another part of it, quite frankly, is that the world is so connected. A hundred years ago, a COVID outbreak or in China, would’ve stayed in China, localized to a local region, a few people would’ve died, and then perhaps it would’ve died out. But before we even defined COVID in January of 2020, it had already spread around the world just because people travel. So, I think we will be at increased risk for pandemic spread of infectious diseases. It’s simply inevitable. And I think we have to simply be prepared for it. Quite frankly.

Lopez: I always feel better when I’m informed, and Dr. Zurlo never fails to keep us very informed.

Williams: That’s true. I mean, there really is a lot going on right now. And reminder that we will post a full transcript of our interviews on the Health Nexus in case you’d like to refer back to anything we discuss today. We’ll link that in our show notes.

Lopez: If you enjoy our podcast, we truly appreciate a rating on Apple, Spotify, or wherever you listen to podcasts. We love your feedback.

Williams: Production support for today’s episode provided by Brittany Rafalak and Barbara Henderson. We’re your hosts, Carly Williams

Lopez: and Jess Lopez. Thank you for listening.

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