IRA FLATOW: This is Science Friday. I’m Ira Flatow. 100 years ago this month, the 1918 flu pandemic began sweeping across the globe, killing 50 to 100 million people. And as we reach the peak flu season here in the northern hemisphere, by all accounts, this year is one for the books, though, frankly and thankfully, not on the scale of 1918. The virus is doing something experts have never seen before. It’s spreading across the continental US all at the same time in every one of the 48– 49 states, actually. That’s never happened, and experts don’t exactly know why.

Not only that, but the flu is more severe. Hospitalization rates are up from 14 to 23 people per 100,000 as of early January. Those are some scary numbers, but the flu vaccine remains effective against this year’s dominant strain only about one third of the time. So why still so low? Here to help us grapple with what a severe flu season means is Alicia Fry, medical epidemiologist in the influenza division at the Centers for Disease Control and Prevention.

And we want to know if your community has been hit hard by the flu. Do you have any questions about vaccine effectiveness? Give us a call. Our number, 8440724-8255. You can also tweet us @scifri. Welcome to Science Friday, Dr. Fry.

DR. ALICIA FRY: Thank you.

IRA FLATOW: Give us a brief idea what the difference between an active flu season and a severe flu season, like the one we’re having now, is.

DR. ALICIA FRY: OK, well, I think when we think about this season it’s important to think about two things. One is how widespread the disease is, and two is, what is the severity? And when we think about severity, we usually look at outpatient visits, hospitalizations, and death– so, widespread. As you mentioned, this year is really almost unprecedented in the fact that all 49 states are reporting widespread activity really all at the same time.

So normally, what we see is maybe the flu starts in one region of the country and then will slowly move to other regions. And so while one local community could have a lot of activity, we don’t see it everywhere. And right now it’s really odd in that everybody is having a lot of flu right now.

And as far as severity, all of our indicators are tracking very similar to other seasons when H3N2 viruses were the main virus that were circulating. So this year that is the main virus circulating, and similar to previous years, we are seeing higher rates of hospitalizations and higher rates of outpatient visits. And we expect we will see higher rates of death by the end of the season. So how this will compare to all the previous years as far as severity– we’ll really have to wait until we see the full season, but right now it looks very similar to other H3N2 seasons.

IRA FLATOW: So what you’re saying is that the people have an idea that the vaccine is not as effective this year as it is before, but you’re saying against certain strains, like the H3N2, it is as effective as previous years.

DR. ALICIA FRY: Well, let’s talk about vaccine effectiveness now.

IRA FLATOW: Yes.

DR. ALICIA FRY: So we monitor how well the vaccine works every year, and we do that with several networks that we have. And right now we are actively enrolling patients into those networks. So we don’t know exactly how well the vaccine is working this year, because it’s just a little too early for us to know that, but we can look at last year and previous years. And we can get an idea of what we expect this year.

So last year, the influenza vaccine contains the same H3N2 vaccine virus that it does this year. And the circulating viruses were fairly similar, as well. So if we look at how well the vaccine worked last year, overall it worked about 40%. So it reduced the likelihood of going to the doctor for an outpatient visit related to influenza by 40%. And specifically against H3N2, the vaccine effectiveness was 33%.

Now in contrast, when we looked at the vaccine effectiveness against the influenza B viruses, it was higher. It was about 54%. And that difference where we see a lower effectiveness against the H3 compared to N viruses and even compared to H1 viruses, which we didn’t have last year, but we’ve seen in previous years– we’ve seen that difference before. So there things about the H3N2 vaccine and virus that are sort of working against it and making it harder for that vaccine to be as effective, I think, as the other components of the flu vaccine.

IRA FLATOW: Thank you for taking time to be with us, Dr. Fry. Alicia Fry, medical epidemiologist at the influenza division at the CDC. Thank you very much.

DR. ALICIA FRY: Thanks.

IRA FLATOW: This year the flu vaccine is predicted to be, as Dr. Fry said, about 33% effective against the H3N2 strain of the virus. Scientists have been hunting for a so-called universal vaccine for years, which could attack all the strains of influenza and be much more effective. According to new research published in the journal Science this week, we may be a bit closer to that goal. Joining me to discuss it are my guests, Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, and Presidential Medal of Freedom awardee. Dr. Fauci, welcome back to Science Friday. Dr. Fauci, are you there?

DR. ANTHONY FAUCI: Yeah, I’m here. Sorry. It’s good to be with you.

IRA FLATOW: Thank you. Kathleen Sullivan, professor of Pediatrics at the Children’s Hospital of Philadelphia. Dr. Sullivan, welcome back to Science Friday.

DR. KATHLEEN SULLIVAN: Thank you so much.

IRA FLATOW: Dr. Fauci, everyone knows getting the flu shot is no guarantee against the flu, but we’re learning that the effectiveness of the vaccine is much worse than we all think it should be, something like 30%, 34%, to 40% against this year’s dominant strain. Give us an idea why the numbers are so low.

DR. ANTHONY FAUCI: Well, the reason is several, really, Ira, but the important thing is that we don’t get a really good match. The match this year that we have with the virus to the vaccine is not an optimal match. When you look at the efficacy of influenza vaccines in general and you look at all the different years for the last 10 years or so, the best we generally do is about 60%. On a really, really bad year, we can do as low as 10%. And as you just heard from our colleagues at the CDC, we project that it likely will be around 30% or so this year, even though you never know for sure until the end of the year.

And what we really need to do– and you mentioned it when you were just talking about it before. We really need to get a vaccine that is making a response against the part of the virus that does not change from season to season. We continually have to chase, as it were– is the word I use– the influenza from season to season to try and get a good match, because the part of the virus that we make an immune response against generally is that part of the virus that tends to change or drift from season to season, or even change an awful lot when you get a brand new influenza like with a pandemic.

There are parts of that virus that don’t change very much from season to season at all. They’re constant parts, and what the goal of a universal flu vaccine is to make a response against that part of the virus that doesn’t change. And if and when we do– and I think it’s going to be when, Ira. It’s a scientific challenge. Then, actually, I believe we’re going to have a much greater efficacy from season to season and not have to worry about always trying to catch up with the changing flu, because unlike other viruses like measles and others that don’t change very much at all, flu has a tendency to change a lot and readily mutate.

IRA FLATOW: We’ve been on the air 27 years, and almost every year I have you come on and talk about the flu season, and you keep saying the same thing, where you define something against the part that doesn’t mutate. What is the difficulty here? Why is that so hard?

DR. ANTHONY FAUCI: Well, Ira, the body does not like to make a response against that part because the part that changes is what we call immunologically dominant. The immune system would rather make a response against the immunodominant. In some respects, that’s good news. The bad news is that the immunodominant part is the one that changes a lot. We have just recently been able– because we now have a new way of approaching vaccine development, this idea of having to grow the virus either in eggs or in cells is not only antiquated. It’s just not the way you really want to present a particular form of the virus to the body.

So when you’re looking at a universal flu vaccine, you can take just that part of the virus that you want the body to make an immune response to and present it in a way that hopefully will make a robust response. So even though you and I have been talking about this, only recently within the last five to seven years has the structural biological techniques that we have allowed us to actually do that– namely, to present to the body the kind of thing we want it to respond to and essentially force it to respond to that.

IRA FLATOW: There was some new research out this week that comes at it from a different angle. Scientists actually improved immunity to the flu virus by making the virus stronger, rather than weaker. Dr. Sullivan, can you explain what they did?

DR. KATHLEEN SULLIVAN: Yes, it seems completely backwards, right? I give these scientists a ton of credit. They really decided to just throw out everything we assumed about making a vaccine, and just make it topsy turvy, and figure out a new way. And so what they did was they took the chromosomes of the influenza virus apart. They just disassembled the virus, and then they made a series of tiny changes, reassembled thousands and thousands of viruses that just differ by a teeny tiny amount, and then put them in a test tube, and said, in a test tube, can we identify some of these changes that actually make the virus better at inducing an immune response? And they were able to, and they found eight specific mutations.

And so they made an artificial virus based on the circulating– you heard about the different strains that are out there. They made an artificial virus based on H1N1 that’s especially good at inducing an immune response. In other words, the cells recognize that virus as being foreign better than just the standard old influenza. Now, that seems a little bit backwards, but it’s actually genius because what that does is it makes the rest of the immune system more likely to make one of these protective responses that Tony is talking about. That’s what we need.

So if you think of the flu virus as like an M&M candy, when we make antibodies to it, we’re making it to the color. So maybe we make a great antibody to green, but then when the red M&M comes around, we don’t really have antibodies to it. But what these people did is they generated such a strong immune response it was to the chocolate in the middle, the part that doesn’t change very much. And so this was, as you can imagine, a huge amount of work to make all these thousands of viruses, but by using this incredible brute force approach, they did end up making a better vaccine.

IRA FLATOW: Now, Dr. Fauci, isn’t this something like what you were saying? You attack the chocolate instead of the color?

DR. ANTHONY FAUCI: Exactly, Ira, and there are multiple different ways of approaching the concept of a universal flu vaccine. What was just described by Dr. Sullivan is a very elegant technique. It’s been done now in mice and in ferrets. The big majestic leap that you and I have been talking about for years is, is it going to work in a human? And I hope it does, because if it does, then that’s yet again another step closer in the same way as many other approaches with different platforms– are trying to get to the same goal.

So we’re really, Ira, talking about the same thing. How do you get the body to make a response against that part of the virus that just doesn’t change? And if you get a really good universal influenza vaccine, we wouldn’t have to worry about the kinds of uncertainties that we have from year to year. And there are some elegant scientific ways to get there. You’ve just heard a description of one, but there are others.

IRA FLATOW: I’m Ira Flatow. This is Science Friday from PRI, Public Radio International. There may be elegant and wonderful scientific ideas, but is there any hard, cold cash to get this stuff–

DR. ANTHONY FAUCI: Yeah, what do you mean by hard, cold cash? We’ve made the universal flu vaccine, Ira, really essentially the number one priority of our institute, the Infectious Disease Institute. We have a lot of other important priorities, but it’s just become clear to me, as a director, and my colleagues here that we really have to put a full court press on this, because this is something that we’ve been chasing, as you know. You mentioned it earlier in the show that we’ve been talking about this for a long time. We’ve really got to get to that end game.

IRA FLATOW: Dr. Sullivan, any limitations? I mean, you came up with good news, but of course all good news has boundaries to it.

DR. KATHLEEN SULLIVAN: Yes, I think there are some real reasons to go into this cautiously, although I’m enormously excited about that technology. I think it was really just so creative and innovative, and one of the nice things about their technology is that, at least in theory, you could apply it to other viruses. You could think about it for Zika or for Ebola, but you asked if there are limitations.

And so they made a man made virus with certain mutations in it, and Tony just talked about the fact that influenza really likes to mutate. It likes to change its own genetic heritage, and so you would worry that maybe some of the mutations that were made to generate this artificial virus could back mutate. And then you’d be giving a virus that could cause disease, rather than protect from disease. So that’s one thing we always worry about with live vaccines.

And I think the other thing that might not be so obvious, but this vaccine strain virus that they generated is so powerful and so good at inducing an immune response you sort of wonder if, when the wild type virus comes along, if, in some cases, people might overshoot. So one of the harmful aspects about avian flu, those H5N1s that we sometimes hear bubbling up in Asian, and chicken farms, and so forth– one of the reasons those are so harmful is they actually cause the immune system to go into a kind of frenzy. And in that frenzy, the immune system starts attacking our own body. And you sort of wonder if this vaccine is going to end up in those circumstances generating something that’s a little too good.

IRA FLATOW: I get you. I get you. Let me get a quick call in from Maria in Sacramento. Hi, Maria. Quickly.

MARIA: Hi. Yes, I’ve been working in public health for over a decade now, and one of the major concerns patients have– especially parents– is the ingredients of the vaccine itself used like with any other vaccine, for example, MMR, but for the flu season, because it’s annually, a lot of them are concerned on that content of aluminum, and mercury, and all the other ones listed. Is the CDC working– or any of the pharmaceutical companies on removing those ingredients, hopefully, once the universal vaccine is out?

IRA FLATOW: Let me get an answer for you. Dr. Fauci, Dr. Sullivan?

DR. ANTHONY FAUCI: Yeah, well, first of all, the doses of the influenza– most of them have absolutely no preservatives in them at all– single vial dose. The multi-dose ones have a degree of preservative in it that has been clearly shown to be completely safe, and I think you keep getting back to people saying, understandably– I mean, the idea of questioning when somebody is going to put a substance into you– but what’s in the vaccine has been proven to be completely safe from the standpoint of ingredients. Now, every once in a while, in a rare case, someone will have an adverse reaction to a vaccine, but that is extraordinarily rare.

IRA FLATOW: All right, there you have it. Dr. Anthony Fauci, head of the NIAD, and Kathleen Sullivan, professor of Pediatrics at Children’s Hospital in Philadelphia. Thank you both for taking time to be with us today.

DR. ANTHONY FAUCI: Thank you. Good to be with you.

DR. KATHLEEN SULLIVAN: Thank you.

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