IRA FLATOW: This is Science Friday. I’m Ira Flatow. We’re more than halfway through August, and thoughts are turning to back to school– yes. For parents and pediatricians, back to school means another year of trying to keep kids safe from COVID-19. We now have vaccines for our youngest kids. But what if your kid has already been infected naturally? Do they still need a shot? And what about other diseases in the news like monkeypox and polio?

Well, to gear us up to go back to school healthy and protected, I’m joined by my guest, Dr. Paul Offit, director of the Vaccine Education Center at the Children’s Hospital of Philadelphia. He’s a longtime pediatrician and vaccine researcher based in Philadelphia. Welcome back to Science Friday.

PAUL OFFIT: Thanks. I’m happy to be back. By a long time, I assume you mean old. And yes, that’s all true.

IRA FLATOW: [LAUGHS] Both of us. Let’s talk about the biggest difference between this back to school season and last year’s, where all kids over six months of age can get vaccinated against COVID-19. How do you think this will change the amount of transmission we’ll see in schools?

PAUL OFFIT: Well, I think we’re much better off than where we were. I mean, think about when this virus came into this country in January 2020. We had a completely susceptible population. We didn’t have monoclonal antibodies. We didn’t have antivirals. We didn’t have vaccines. And this virus rolled through this country, causing hundreds of thousands and millions of hospitalizations and intensive care unit admissions and deaths. I mean, now fast forward to where we are now. We have monoclonals. We have vaccines. We have antivirals.

And more importantly, we have probably about 95% population immunity, meaning people who have been naturally infected or vaccinated or both. So I would have to believe that the level of disease, meaning important disease, meaning the kind of disease that caused you to be hospitalized or go to the ICU, or worse, die, is going to be way down from where we were in the previous two fall seasons.

IRA FLATOW: That’s great news. Let’s talk about something we get asked a lot by our listeners– what to do about vaccines if your kids have had recent COVID-19 infections. Let’s say you have a four-year-old who got COVID over this summer. Should they get vaccinated?

PAUL OFFIT: So the question that I’m often asked is, does natural infection protect you against severe illness? Because that’s really the goal of this vaccine, is to protect against severe illness. This is a shortened incubation period, respiratory infection. So you’re not going to protect against mild disease. Even if 100% of the world were vaccinated and even if the virus never mutated, you still would have mild disease.

So what to do now? I think that if you’re naturally infected, the odds are you are protected against severe disease, but it really, to some extent, depends on the nature of the natural infection. So for those who are mildly infected or asymptomatically infected, they generally develop lower frequencies of memory B-cells, memory T-cells, the kind of cells that are important in protection against serious disease.

So when people ask me the question, look, my child was naturally infected, had a mild infection, had an asymptomatic infection, do I need to get vaccinated, my answer to that question is yes because then you can assure that they will then develop the kind of immunity that will likely lead to fairly long-lived protection against serious illness. It assures that because when you’re naturally infected, you’re given a variable dose of the virus, if you will. But when you’re vaccinated, you’re given a known dose.

IRA FLATOW: So you’re saying the immunity from the vaccine is not equal to the immunity from an infection?

PAUL OFFIT: I’m saying that the immunity from the infection can be variable, and it can be as good as the vaccine, but you don’t know because it, to some extent, depends on the level of symptomatology with that natural infection.

IRA FLATOW: I get it. I get it. Now parents, of course, have options. There are different vaccine makers out like Pfizer and Moderna. Do you recommend one over the other for our youngest kids?

PAUL OFFIT: Well, so the Advisory Committee for Immunization Practices on which I’m a voting member did meet about these two vaccines in mid-June and didn’t make a distinction between the two.

But arguably, with Moderna’s vaccine, which is a two-dose vaccine, as [INAUDIBLE] from Pfizer’s vaccine, which is a three-dose vaccine, you can argue that your protection will then occur sooner after that, say, first dose of Moderna’s vaccine, which would be arguably six weeks later, which is just two weeks after that second dose, as compared to Pfizer’s vaccine, which is going to be closer to 16 to 18 weeks later. So both vaccines are likely to be equally effective at preventing mild to moderate to severe disease. But you could argue that you’re going to be immune quicker with Moderna’s vaccine.

IRA FLATOW: Mm-hmm, and for babies and toddlers who’ve never been vaccinated, are they going to be protected from the variants also that are going around now?

PAUL OFFIT: Now the good news is that while it’s true that these vaccines, whether it’s Pfizer’s vaccine or Moderna’s vaccine or Novavax’s vaccine, were all made to protect against the original strain, the original Wuhan [INAUDIBLE] strain. We’ve now gone through many variants. And the key variant is the most recent one when Omicron crossed the line because with Omicron, you had a virus that was so mutated that you really weren’t very well protected against mild disease, the so-called immune invasive strain. And that’s also true with these Omicron subvariants, like BA.4, BA.5.

But the good news is, what never did mutate is the so-called epitopes, which are immunologically distinct regions on SARS-CoV-2 spike protein that are recognized by T-cells, so-called T-helper cells or cytotoxic T-cells, because those are the cells that are most important for protecting you against severe disease. So although you are not as well protected against mild disease with Omicron infection or with Omicron subvariant, you are still well protected against severe disease. And I think people need to understand that because that’s the goal. The goal is to keep people out of the hospital, keep them out of the ICU, and keep them out of the morgue.

IRA FLATOW: How much hesitancy are you seeing from parents to get young kids vaccinated?

PAUL OFFIT: Enormous amount of hesitancy. I mean, you look, for example, as you go down the line to younger and younger children, there’s greater and greater hesitancy. So for example, for the 12 to 15-year-old, the uptake in that group is about 60% to 65% of children in that age group have been vaccinated. For the 5 to 11-year-old, it’s closer to 35%. For the less than five-year-old, it’s about 5%.

So parents are hesitant to give their child this vaccine, and I think, in part, because it’s always difficult, I think, to watch your child inoculated with a biological agent which you might not understand very well and so are susceptible to the kind of misinformation that surrounds these vaccines. And more importantly, I think people just consider their children to be invulnerable. They can’t imagine that anything bad would ever really happen to them.

But if you ever pay attention to these parent advocacy groups, like Families Fighting Flu, Meningitis Angels, National Meningitis Association, these are parents whose children have suffered or died from vaccine preventable diseases who had chosen not to vaccinate them. And all those parents tell the same story. I can’t believe this happened to me until it happens to them.

IRA FLATOW: This is so different from we baby boomers, our generation, which we welcomed all the vaccines that came by.

PAUL OFFIT: Yes, it was a different time. It was a more trusting time. I mean, I’m a child of the ’50s. I remember the pol– when I was five years of age, I was in a polio ward for about six weeks. I certainly remember that disease. I remember my mother crying when that vaccine was licensed and recommended. But think about it. In 1955, when Jonas Salk made his polio vaccine, five companies stepped forward to make it. One company made it badly. Cutter Laboratories of Berkeley, California failed to fully inactivate that virus.

As a consequence, 120,000 children were inadvertently inoculated with live, fully virulent, dangerous polio virus. 40,000 developed abortive or short-lived polio, 164 were permanently paralyzed, and 10 were killed. I would say that was the single worst biological disaster ever to happen in this country. And it, in no way, shook the public’s confidence in vaccines or vaccine makers.

IRA FLATOW: Yeah, so while we’re on polio, because polio is around now, you and I, who got that vaccine back in the ’50s, are we still protected from it?

PAUL OFFIT: Yes. Well, I mean, I was born in 1951. So I got the inactivated vaccine, meaning Jonas Salk’s vaccine, and then also got the vaccine on sugar cubes, which was Albert Sabin’s vaccine. So I was inoculated arguably with the so-called sequential schedule, meaning inactivated vaccine, oral polio vaccine. So the question is, do we have long-lived memory response? Are we still protected against polio having received those vaccines as children? Yes, the answer is yes.

IRA FLATOW: And what about parents getting polio vaccines for their kids now? They should go out and get them most definitely?

PAUL OFFIT: Most definitely. The problem with polio is, we’re never going to eliminate polio from this country until we stop giving the oral polio vaccine. I mean, the oral polio vaccine was great in the sense that we were able to eliminate polio from our country by the 1970s. We were able to eliminate it from the Western hemisphere by 1991. That’s what the oral polio vaccine gave you.

But the price you paid for the oral polio vaccine was that in rare cases, very rare, roughly one per 2.4 million doses, that vaccine virus could essentially revert to so-called neural virulent type, meaning you could be paralyzed by the oral polio vaccine. And so although we eliminated polio from this country by the late ’70s throughout the 1980s, throughout the 1990s, through those 20 years that we continued to use the oral polio vaccine, every year, 8 to 10 children will be paralyzed by that vaccine.

And some who came in contact with those who had been inoculated with that vaccine where the vaccine virus had reverted, essentially, to wild type. And that’s why in the year 2000, we stopped using the oral polio vaccine in this country and went back to the inactivated vaccine.

IRA FLATOW: Mm-hmm, I know I got us off on the polio track, but I still have so many questions about COVID. I want to go back to some of those because we’ve been asked so many things from our listeners. Getting back to getting kids vaccinated, this is a two or three-series vaccine for kids under five. I mean, when should they start if they want to be adequately protected before the school year begins. I mean, and is it too late to time it perfectly?

PAUL OFFIT: Well, I think you should start now. Again, this virus is going to be with us for years, if not decades. So you want your child to be protected. It’s a two-dose vaccine in the case of Moderna’s with those two doses separated by about a month. It’s a three-dose vaccine for Pfizer where the second dose is three weeks after the first, and the third dose is two months after the second.

So sure, get vaccinated. Now but you don’t have to go to school to be at risk. I mean, you’re at risk because these viruses are circulating even now. It is, at its heart still, I think, a winter respiratory virus. So you do want to be protected in the fall and winter, but get vaccinated now.

IRA FLATOW: And for older kids who got two doses of the vaccine and then got COVID, should they get boosted?

PAUL OFFIT: I don’t think so. I think that natural infection following two doses was the boost.

IRA FLATOW: A-ha, a-ha. And like the vaccine for adults, there have been some reports of side effects in young kids. Does that change how you feel about advising parents to get their kids vaccinated?

PAUL OFFIT: Well, what you worry about is, it’s not the sort of mild side effects, meaning pain or redness at the injection site, fever, headache, joint pain. I mean, those are parts of your immune response. I mean, those symptoms are symptoms of an immune response. What you worry about, at least what I worry about, is myocarditis, which is inflammation of the heart muscle.

I mean, when that vaccine was then recommended safe for everyone over 16 years of age, you knew that for the, say, 16 to 17-year-old male after the second dose, usually within a week of the second dose, those people could get myocarditis, inflammation of the heart muscle, which although short-lived and generally transient and self-resolving, is still quite worrisome. And it was about one in 20,000 risk.

And so you worried– I worried– as we moved down to the 12 to 15-year-old and the 5 to 11-year-old, since this was a young male phenomenon, would it be even greater as we got to younger age groups? And that wasn’t true. It was less and less real. So it wasn’t one in 20,000, or one in 50,000, or one in 100,000.

But remember, SARS-CoV-2 virus also causes myocarditis. I mean, there was a study done among athletes at Ohio State University. So these are men and women between 18 and 22 years of age. And what they did was they looked at people who had COVID, whether they had symptoms, cardiac heart symptoms or not.

Everyone got a cardiac MRI to answer the question how common was myocarditis with COVID, and the answer was one in 45 people had had evidence of myocarditis. 2/3 of them were asymptomatic, 1/3 of them were symptomatic, but so a choice not to get a vaccine is never a risk-free choice. It’s just a choice to take a different risk. And I would argue, if you’re risking COVID, which you are, it’s a choice to take a more serious risk.

IRA FLATOW: This is Science Friday from WNYC Studios. We’re talking with Dr. Paul Offit, pediatrician and a vaccine expert based in Philadelphia, Pennsylvania. OK, let’s shift gears to another infectious disease that’s been in the news a lot. And of course, I’m talking about monkeypox. We’ve heard concerns from parents who worry that if it gets into the general population, that spreads in schools could be a nightmare. What’s your take on this?

PAUL OFFIT: I guess I don’t see that. I think this is a virus, which is, for the most part, spread by skin-to-skin contact. If you look at where the cases occur, 95% of these cases are in men who have sex with men, and especially men who have many sexual partners. So can children get this virus? Yes. They get it typically by having an adult in the home who has monkeypox and whom they have either skin-to-skin contact or end up sharing things like blankets or towels. That’s where you see monkeypox.

Where you worry about school spread is for viruses that have respiratory route as an important part of pathogenesis, meaning that the virus is contained in small droplets that are spread from one person to another by talking or sneezing or coughing. That’s not this virus. So I don’t really see this as a problem in school.

IRA FLATOW: Mm-hmm, because we know the kids are notoriously unhygienic, right? And they’re going to be touching and feeling everything they get their hands on.

PAUL OFFIT: Yes, that’s exactly who they are.

IRA FLATOW: Yeah, yeah. Do you think we’re going to get to a point where we start giving the monkeypox vaccine to kids, though, somewhere along the line, or no?

PAUL OFFIT: I don’t think so. The vaccine that’s currently being used is the so-called JYNNEOS vaccine– I should take a step back– which is designed to protect against smallpox, human smallpox. There’s not really a monkeypox specific vaccine. This is a vaccine designed to prevent smallpox, which is really the way the first vaccine was made. I mean, when Edward Jenner made his smallpox vaccine, he used cowpox because it was antigenically– now we know– antigenically related enough so that infection with one could protect against disease caused by another.

So there’s a lot of this sort of cross-species protection. So this JYNNEOS vaccine is made by taking really the original smallpox vaccine– it was the so-called Ankara strain– and then modifying it by passing it like 500 times in chick embryo fibroblast cells, which significantly weakened that virus and dramatically, really virtually eliminated the side effects, which were significant associated with the smallpox vaccine, the original smallpox vaccine, which could cause myocarditis, pericarditis, and serious illness. So we’ve eliminated that.

I think there’s not a lot of vaccine available is part of the problem. So what the government decided to do is to be able to expand the amount of vaccine by essentially giving 1/5 of the dose and giving it intradermally, which makes sense, actually. I mean, the intradermal area, the area just under your skin, is rich in the kind of so-called antigen presenting cells like dendritic cells that makes that a more effective vaccine. Essentially, it mimics, in many ways, the scarification procedure that was used when you and I got the smallpox.

IRA FLATOW: Yep, scratching the skin with– yeah.

PAUL OFFIT: Exactly.

IRA FLATOW: Scratching left you with a scar. OK, I think we’ve covered it all. I just want to ask you if you have any parting words about infectious diseases this school year that you want to leave with parents.

PAUL OFFIT: Well, just get your child vaccinated. I think our job as parents is to put our children in the safest position possible. And vaccines afford that safety.

IRA FLATOW: That’s it. Well, as always, thank you so much, Dr. Offit, for taking the time to be with us today.

PAUL OFFIT: Thank you. It was my pleasure.

IRA FLATOW: Dr. Paul Offit, director of the Vaccine Education Center at the Children’s Hospital of Philadelphia.

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