MR. KOJO NNAMDIFrom WAMU 88.5 at American University in Washington welcome to "The Kojo Nnamdi Show," connecting your neighborhood with the world. We see the names and the headlines and they certainly seem scary, West Nile virus, swine flu, avian flu, but are they as scary as they seem to be? How likely are you or your child or grandchild to get one of these infectious diseases?

MR. KOJO NNAMDIIn the past two weeks, Maryland had its first outbreaks of swine flu and Virginia reported its first West Nile virus cases. And despite decades of science-tackling vaccines and disease, the United States is currently experiencing its worst outbreak of whooping cough in a century.

MR. KOJO NNAMDIWe find out what's going on with viruses, flu and infectious disease. Ask questions about back-to-school vaccines and find out if the experts recommend skipping this year's country fair or at least the agricultural booths. Joining us in staff is Roberta DeBiasi. She is a pediatrician specializing in infectious diseases at Children's National Medical Center and a Professor of Pediatrics at George Washington University. Roberta DeBiasi, thank you so much for joining us.

DR. ROBERTA DEBIASIThank you.

NNAMDIAlso joining us by phone is Steven Salzberg. He's a Professor of Medicine and Biostatistics at the Institute of Genetic Medicine at Johns Hopkins University School of Medicine. Steven Salzberg, thank you for joining us.

PROFESSOR STEVEN SALZBERGGlad to be here.

NNAMDIWe're inviting you, the listener, to join the conversation also by calling us at 800-433-8850. Are you changing your behavior based on fear of catching a flu or virus? Why or why not and would you even recognize measles or the mumps if your child got them? Why or why not? Call us at 800-433-8850 or send email to kojo@wamu.org. Send us a tweet @kojoshow or simply go to our website, kojoshow.org, and join the conversation there.

NNAMDILast week, the FDA approved the recipe, if you will, for this year's flu vaccine. Interestingly enough, prevention against the swine flu is included. Why is that, Roberta?

DEBIASIEvery year, we come up with our new combination of viruses that will be included in our seasonal influenza vaccine and it always has three. And we usually have 2As and 1B type and since the pandemic flu in 2009, which was a swine influenza variant, we have included that in the seasonal vaccine and once again, it is included again.

DEBIASISo I think when I was on your show a couple of years ago, we talked about how things are very exciting when a new virus bursts on the scene as it did in 2009. But then over a couple of years, it becomes the routinely circulating virus and that's why it's in the vaccine.

DEBIASIThe newest swine virus that you hear about in the news is actually not going to be in the vaccine.

NNAMDIWhy not?

DEBIASIIt just happened so there wasn't time enough to put it in the vaccine. As we talked about and I think people are aware, the current way we make vaccines, you need at least a six-month head time to figure out what to put in the vaccine from year to year and this hasn't been appreciably circulating until very recently so it really wasn't on the radar until recently.

NNAMDISteven Salzberg, occasionally we hear about scientists creating a universal vaccine. Are we getting any closer to that reality?

SALZBERGWell, if you follow the scientific literature, I would say that, yes, we are getting closer. The difficulty we have with the flu virus is that it mutates very quickly from year to year so the virus is always a little bit different. And the parts of the virus that the immune system sees are the parts that are changing and so you basically want to put something in the vaccine that is going to familiarize yourself with your immune system with the virus.

SALZBERGSo it's like showing a picture to your immune system and that picture is changing so it's hard to find an unchanging picture of the virus that your immune system can see that isn't going to be different next year. That's the problem with a universal vaccine. But there is progress being made. I think it's quite a few years away.

NNAMDICare to comment on that, Roberta?

DEBIASINo, I agree with what he said. You know, eventually, we hope we get to molecular techniques for making vaccines such that instead of taking six months and growing them in eggs and harvesting from eggs, which is why it takes so long, that we can get into more molecular techniques that would allow us to have a more rapid response for the vaccine development.

NNAMDIOkay, in that case, I can move on. What is it about pigs? Is it something special that makes pigs particularly good at passing along viruses to humans?

DEBIASIThey're just so darn cute. No, but really what it is, is, you know, influenza viruses circulate amongst different species and as a rule, they like to stick with their own species. So there are bird viruses. There are pig viruses. There are human viruses. However, a pig is one of the species that can be infected by other species' flu viruses and they act as a nice little mixing ball, if you like to think about that as a sort of lotto where the different, little pieces of the genome of flu can re-assort.

DEBIASISo you could have a pig infected with a bird virus, a human virus and a pig virus at once, have a re-assortment occur and then you have this new virus that is technically a pig virus, but could then go on to infect a human, which is what's going on right now.

NNAMDIAnd Steven Salzberg, it's my understanding that flu viruses have adapted to several mammal species, including pigs, dogs and horses. There's a new strain that can spread among seals and that's a reason for serious concern. Why?

SALZBERGA new strain could spread among?

NNAMDISeals.

SALZBERGAmong seals, I can't answer that. I'm actually not familiar with that strain.

NNAMDIWell, maybe Roberta is.

DEBIASIWell, there has certainly, in almost every species, been an influenza virus that can infect it so I know back when we had this big pandemic that we were worried about in 2005 in Southeast Asia, people could detect these viruses in tigers and ferrets and all kinds of unusual animals. But to my knowledge, including seals, there's not been a huge concern that those have jumped into human species nor that there's a re-assortment with human viruses.

NNAMDIWell, Steve Salzberg, you can speak about the idea of just mammals.

SALZBERGWell, so I mean, what we should worry -- I mean, we worry about any kind of infectious disease we see out there, but not always justifiably so. And what we've seen in the past century are several major flu pandemics. And we're always worried about another one.

SALZBERGWe just had one so that suggests there's not going to be another one soon. The recent ones were in 1918 with the well-known Spanish flu, which was the deadliest flu in history. The 1957 pandemic and the 1968 pandemic and then the 2009 pandemic, so for those four pandemics, the flu viruses came from birds in three of them and then the most recent one came from pigs.

SALZBERGSo it's historically, it's very unlikely, but not impossible. It's very unlikely that other animals, mammals or otherwise, would be the source of the next pandemic. We're much more concerned about birds and pigs because that's where we've seen the pandemic strains emerge before.

NNAMDIIf you have concerns about swine flu or West Nile virus cases or anything else, you can call us at 800-433-8850. Send email to kojo@wamu.org We're talking with Steven Salzberg. He's a Professor of Medicine and Biostatistics at the Institute of Genetic Medicine at Johns Hopkins University School of Medicine and Roberta DeBiasi is a pediatrician specializing in infectious diseases at Children's National Medical Center. She's also a Professor of Pediatrics at George Washington University.

NNAMDISo Roberta DeBiasi, should parents take their kids to the petting zoo or the county fair?

DEBIASIYeah, so part of the reason that we're seeing increased cases since August -- and I guess we should probably give a little bit of background there.

NNAMDIPlease do.

DEBIASIThere have been about 225 cases in total since we've been following this since about July of this year and the bulk of those are in two states, in Indiana and Ohio. There have been a smattering of cases in other places and as you alluded to, there were six reported cases in Maryland down in the eastern shore.

DEBIASIWe have not had a confirmed case in D.C. yet and there has not been a case confirmed in Virginia yet, to my knowledge. But so we're following this closely, but what we've noticed, of course, is that when there are fairs and there are people in contact with pigs, that probably has a large impact on why we're seeing so many cases and because this is when all the fairs are.

DEBIASIHaving said that, of all those cases, they really have been relatively mild cases so we haven't had deaths from this and there have been very few hospitalizations and those that have been hospitalized have fully recovered. So there's nothing about this particular virus so far that makes us concerned that's it is causing more severe disease. But it's something that we, as epidemiologists, want to look at and see if there continues to be more and more transmission.

DEBIASIIt also appears so far that all those cases, those 225 cases, you could link them back to a direct contact with a pig or indirectly, you know, they worked with a family member that handles pigs. So there are a few cases where there probably was human to human transmission without the pig being around, but the vast, vast majority are with someone in direct contact with a pig.

DEBIASISo now to get to your question, yes, you can still go to the fair.

NNAMDIThank you.

DEBIASIWhat is recommended is if you're in a high-risk group for complications from the flu, and that would be children less than five years, someone over 65 years of age, someone who is pregnant, someone with a chronic medical condition, someone who is immune-compromised with neurologic disorders, maybe just skip the pig area. It doesn't mean you can't go to the fair, but those high-risk groups, the CDC says maybe skip that area.

DEBIASIIf you're not in a high-risk group or even if you are in a high-risk group and you really want to see those pigs, don't kiss the pigs. Don't bring food into that area. Don't bring your drinks and walk around. Don't chew gum in that area. Don't put your hand on things and put it close to your face. So I think it's just common sense, as far as not trying to have direct contact with secretions from pigs. That's really the main risk factor to date.

NNAMDIAnything you'd like to add to that, Steven Salzberg?

SALZBERGNo that's all very good advice. I agree with that.

NNAMDIWell, I don't want to rain on anyone's parade so I'm hoping we're not just about due for the next infectious disease pandemic. Are we? What are the odds, if you will, starting with you, Steven Salzberg?

SALZBERGWell, we don't really have very good statistics, you know, with only four pandemics in the last century and we think they occur at a rate of about every 10 years to every 40 years. So we had a 40-year gap between '68 and then 2009 and then we had a 40-year gap between the 1918 flu and the '57 flu. And then, in between, we had these very short intervals of only 11, only 10 years -- roughly 10 years between the '57 and '68 flu.

SALZBERGThe reason for a pandemic, the way the flu evolves, the way our immune system responds, from what we understand of that, it's very unlikely that we're going to quickly get another pandemic. What has to happen is a new flu strain has to emerge that is very well adapted to not only infecting humans, but passing from human to human and it has to come from somewhere.

SALZBERGSo that's why we're doing surveillance on pig populations and bird populations and also on the human population. But there isn't a strain, including this new strain that Dr. DeBiasi just mentioned, that looks like it's going to be dramatically better at infecting humans than the strains that are already infecting us.

SALZBERGSo not only does it have to be able to infect us, but it has to displace the current flu because there does seem to be, and there has been for many years, a kind of cross-protection or competition between flu strains. So generally there's one dominant strain per season and so if we're being infected by one strain, other strains don't seem to be able to get to the human population.

SALZBERGSo unless this new strain or some new strain, which will emerge, can also be better able to infect humans than the current strains that are already out there, there isn't that much to worry about. We're always looking, but I think we're not likely to see another pandemic for quite a few years, just based on historical records.

NNAMDIRoberta DeBiasi?

DEBIASIYeah, I think if you -- I agree with that statement and, you know, if we follow the stats, it's unlikely since we just had a pandemic in 2009. But flu is very tricky and it fools us all the time. One thing I'd say about this particular strain, that's circulating is one of the little pieces of the gene does have the same, what is called matrix protein, as the one that circulated in 2009 and that particular segment has been associated with being pretty good at going from human to human.

DEBIASISo that is one of the reasons why we're paying, you know, close attention to this to see if it actually bears out, that it does become good at going from human to human because that's really the piece you need to develop into a pandemic virus.

NNAMDI800-433-8850 is the number to call. Have you vaccinated your school-aged child? If not, why not? 800-433-8850 here is Doug in Washington, D.C. Doug, you're on the air. Go ahead, please.

DOUGYes, Hi Kojo and panel. I'm sorry if my question's not put together correctly, but I was curious about a -- I think it was two years back -- a vaccination was given from the United States to China to deal with Avian flu I think. And I think the Chinese medical community was supposed to take this vaccination and, you know, vaccinate the population. But somehow it was given to the poultry farmers and their -- I guess it made -- they started giving the vaccination to the chickens. And it kinda basically made the vaccination completely ineffective for fighting the virus altogether and all that research and development that went into creating that vaccination.

DOUGSo I'm just -- is this a concern as far as how these once they're developed and how they're used, and if it's not used correctly that it makes all of that, you know, investment in time worthless if the vaccination just doesn't work? Is that a concern for the government?

NNAMDISteven Salzberg?

DR. STEVEN SALZBERGWell, I think what you're referring to is that there have been attempts to control Avian flu by vaccinating the flock of chickens as opposed to -- what's normally done when Avian flu is found in a chicken is that the whole -- the farmer's whole flock is destroyed. And this is pretty devastating. And of course farmers don't want that. And because of that action, which public health authorities take -- not just in the U.S. but in China and other countries too -- it means -- it makes farmers reluctant to report any signs of flu in their chickens 'cause they don't want to lose their whole flock.

DR. STEVEN SALZBERGSo if we had an effective vaccine for bird flu in birds, then it might be an effective way to control it. We don't have that right now. The other thing -- so that's sort of a separate line of research and it's separate from human vaccines and protecting humans. The other thing he's describing is the vaccine becoming ineffective. So that's -- so that may be true for birds but it's certainly true for humans which is more, you know, sort of immediately pressing for us.

DR. STEVEN SALZBERGVaccines become -- the flu vaccine becomes ineffective for the very simple reason that the flu virus mutates much faster than most of the other pathogens that infect us. So most vaccines you get, you just need one or a few shots and you're protected for life or for a very long time. The flu virus -- the flu vaccine actually does protect you against the strain that you're immunized against for a very long -- for a long time, or at least for a few years. But the flu itself doesn't wait around for that. The flue itself is changing and that's what makes the vaccine ineffective.

DR. STEVEN SALZBERGAnd we can't do anything about that. That's just evolution happening. And the reason it evolves so quickly is that it has to do with this molecular biology. It's made of RNA instead of DNA and because of the way it -- sort of the way its biology functions it just mutates very rapidly. So that means it evolves very rapidly.

NNAMDIDoug, thank you very much for your call. We've got to take a short break. If you have called, stay on the line. We'll try to get to your calls. If the lines are busy, go to our website kojoshow.org and join the conversation there. Or send email to kojo@wamu.org. You can also send us a Tweet at kojoshow. Do you or someone you love have a compromised immune system? What preventive measures do you take to keep yourself healthy and free from flu? 800-433-8850. I'm Kojo Nnamdi.

NNAMDIWelcome back to our conversation on infectious diseases, vaccines and of course it's back to school time. So people can be particularly concerned about that. We're talking with Steven Salzberg. He is a professor of medicine and biostatics in the Institute of Genetic Medicine at Johns Hopkins University School of Medicine, and Roberta DeBiasi. She's a pediatrician specializing in infectious diseases at Children's National Medical Center. She's also a professor of pediatrics at George Washington University.

NNAMDIIf you have questions or comments, you can call us at 800-433-8850. Do you work in health care? What are the most common myths or misunderstandings you see about getting vaccinated? 800-433-8850. Steven Salzberg was talking earlier about how the flu virus mutates. Well, earlier this year scientists were trying to learn precisely that and they ended up making headlines. Their work was called controversial. Many people felt it should not be published for fear that it could be misused.

NNAMDIWhat can you tell us about the experiments that they were doing and what was your take on whether it was responsible or irresponsible to do the research and publish the findings? I'll start with you, Robert DeBiasi.

DEBIASIYeah, that was very fascinating research and important research. So these researchers -- to make a long story short -- were able to reconstruct the equivalent of what the 1918 pandemic virus was so that we could study it. Because there was so much severe disease and death in that pandemic that incidentally was not just due to lack of antibiotics. We often thought that and thought, well they just died of bacterial pneumonia. But when we've done studies retrospectively of these patients, it actually was the virus itself that was very severe.

DEBIASISo these researchers over a very long period of time were able to isolate pieces of the actual virus from 1918 and then make recombinant strains so that they could then study this in the laboratory. And it was published because in all of scientific literature things need to be reproduced to be shown to be true. And other people need to be able to access the data so they themselves can develop novel and important research questions. So that's really the crux of it.

DEBIASISo in my opinion it was important research. I think in the molecular age sometimes our regulations are a little behind our research. So this is -- and perhaps Steve would like to comment on that.

NNAMDISteve what's your view?

SALZBERGWell, actually I think Dr. DeBiasi was commenting on the reconstruction of the 1918 flu which is a little earlier. What made the news most recently, which I think is what you described, Kojo, was two papers that appeared where they took the H5N1 Avian flu that we've been watching for years -- it's extremely pathogenic when it gets into humans -- but it's only been infecting humans directly from birds.

SALZBERGAnd these two different groups, one in Wisconsin and one the Netherlands, were able to, in the lab, mutate it so that it became infectious between humans, or at least it seemed to have like -- they didn't, of course, do the actual experiment but from their laboratory data it looked like it would be transmissible between humans. So they basically took a very dangerous bird flu that hasn't really been a problem for humans, but has occasionally gotten into humans with a high mortality rate, and they turned it into something that could be a human-to-human transmissible virus which could cause a major outbreak and possibly even a very deadly pandemic.

SALZBERGSo that's why they were criticizes because this flu virus never existed in nature and why make it? And I fall into the camp of the critics. I think it was extremely irresponsible and they never should've done the work. I understand their motivations to doing the work, their scientific curiosity about what molecular changes make it possible for the flu to transmit from human to human but I just think these experiments were very irresponsible. I haven't said that publicly before. I didn't realize you were going to ask me but I'm willing to go on the record and say that. I think they were irresponsible and shouldn't have done it.

NNAMDIWell, thank you very much for saying that because Steven in Silver Spring, Md. has a question that may not be directly related but is related in a way. Steven, you're on the air. Go ahead, please.

STEVENThank you, Kojo. Love your show. Enjoy listening to it every day. My question is this. Not -- with the terrorists that we have throughout the world, I'm not really worried about the chemical warfare because it takes a lot of military backing and special laboratories and that, but it is the viruses that seem to me, in all of the reading that I've done, to be easier to make. And now we have people publishing papers, as your guests have just talked about, that it's very easy now to make very deadly, very pandemic, perhaps extensively pandemic viruses.

STEVENAnd we have people full of hate who do have this knowledgebase and who have money backing them. If we were hit by these types of viruses -- and forget all the Hollywood movies that that happened and, you know, everybody dies and become zombies -- are we prepared to totally stop a pandemic that would be set by a terrorist group?

NNAMDIWell, I don't know the expertise on national security that either of our guests have here, but is that one of the possibilities that caused you, Steven Salzberg, to feel that the research that was conducted was irresponsible?

SALZBERGYeah, I think that's at least part of it. There's no reason to make it easier for people to be able to synthesize such a virus. I personally don't think it's a likely event at all but an extremely unlikely but extremely damaging or harmful event is still something we should avoid. It doesn't keep me up at night but it just -- I just don't see really why -- in the case of the Avian flu research, I don't think the very minimal benefits really justify the possible great cost of someone acquiring this knowledge and using it in a nefarious way.

NNAMDIAnd, Steven, when we have a broadcast that focuses more on national security you probably will be able to get that question answered. Here is Kathy in Bethesda, Md. Hi, Kathy.

KATHYHi, love your show.

NNAMDIThank you.

KATHYI have a friend who has a pig pet living in her house in the basement. And I've always been uneasy when I go to her house. Am I in danger and what can we do to prevent any kind of problem when we go visit her?

NNAMDITry not to put any lipstick on the pig and kiss it, but here's Robert DeBiasi.

DEBIASIYou stole my punch line.

NNAMDIOh, I'm sorry.

DEBIASIBut, you know, pigs -- the transmission is between pigs. So this sounds like this is a pet pig who's not really out with livestock and probably at lower likelihood of acquiring one of the swine influenza strains that are circulating. But having said that, the pigs actually do develop symptoms when they're ill. They get runny nose. And so if for some reason this was a symptomatic pig then, you know, I would suggest they be seen by a vet.

DEBIASIAnd the same sort of things that we talk about, washing hands, not being in contact with secretions would apply. The same as we say with human-to-human, the same thing would be with you in contact with that pig. But that sounds like a low risk situation to me.

NNAMDIKathy, thank you very much for your call.

KATHYOkay, thank you.

NNAMDIYou too can call us at 800-433-8850. Steven Salzberg, last week officials in Virginia confirmed the first two West Nile cases. Where do you anticipate this going?

SALZBERGWell, West Nile has established itself since it first appeared in the U.S. not that many years ago. It's essentially an endemic strain -- an endemic virus in the population. So I don't think it's going away. Fortunately what happens is when it first hits a region -- well, not fortunately -- when it first hits a region usually a lot of people get sick, some very sick. But it tends to kind of moderate itself pretty quickly after that. I'm not a particular expert on West Nile. I think actually Dr. DeBiasi knows a little more about it than I do.

NNAMDIDr. DeBiasi, Maryland has had five cases so far, D.C. has had one. Texas, we've been seeing on the news, has seen several deaths from West Nile and is now doing aerial spraying. What's your take?

DEBIASIYeah, you know, West Nile virus is an interesting story, as he alluded to. It first came into the Western Hemisphere in 1999 so we really did not have it here until 1999. And really the biggest epidemic we had was over 2003 and 2004. And in that year we had almost 10,000 cases and 275 deaths. So that was really the peak. As it hit our country and spread through from the east coast where it was first seen all the way through the west we saw this increase in cases.

DEBIASIAnd if we look at the data really between that time when it peaked 'til now, it sort of has, as he said, become endemic, so smaller numbers of cases every year but it's there every year, so 1,000 cases, 2,000 cases, 700 cases. It's not that this is something new that we have West Nile virus cases. What has really come to the attention of the media and the CDC is that in this -- just this last part of this year, and particularly in Texas, there have been 700 cases which is kind of already about the amount we had in the last few years for a whole year. So we're kind of ramping up again compared to what we had seen as the trend over the last, you know, ten years.

DEBIASIThere have been 26 deaths, but that amount of deaths is not more as a proportion of cases than we saw when we had those large number of cases in 2003 and 2004. And it's really six states that have 80 percent of all the cases. So it's Texas, Mississippi, Louisiana, Oklahoma, South Dakota and California. But half of those cases are in Texas alone and that's why they're kind of focusing the attention there on an intervention, which would be to spray so that the vector, which is mosquitoes is reduced so that they can interrupt that larger amount of transmission that's being seen.

NNAMDIRobert DeBiasi is a pediatrician specializing in infectious diseases at Children's National Medical Center. She's a professor of pediatrics at George Washington University. Steven Salzberg is a professor of medicine and biostatistics in the Institute of Genetic Medicine at Johns Hopkins University School of Medicine. You can call us at 800-433-8850. Here is Nancy in Alexandria, Va. Nancy, you're on the air. Go ahead, please.

NANCYWhat a timely conversation you're having today because last month my 13-year-old son was diagnosed with whooping cough. And my main question is -- because of my research since then I've discovered that there are a lot of 13 and 14 year olds who are being diagnosed with whopping cough now. And my son was fully vaccinated. Is there an explanation with -- for that?

NNAMDIWhooping cough, also called pertussis. We thought we had all but eliminated, this infectious respiratory disease. Now it seems to be back in large numbers. Robert DeBiasi, who is getting whooping cough, besides Nancy's 13-year-old son?

DEBIASIThere's a lot of people getting pertussis. The important thing is if we look back at the days before we had a vaccine -- so this is back in the '40s -- we had up to 250,000 cases of pertussis a year and 9,000 deaths a year. So we are nowhere near that size of disease transmission. But we really never completely eliminated transmission with our vaccines.

DEBIASIWe know that since the 1980s we've been seeing increased numbers of cases but it's really cyclical. So every three to five years we'll see a little bit of a burst where -- to put this in context to that 260,000 (sic) cases before we ever had a vaccine -- in a relatively normal year we'll have between 3 or 10,000 cases. And then in what we now call a modern day epidemic we'll have 30,000 cases. So we're still tenfold, twentyfold below what we used to see when we didn't have a vaccine. That's the first point.

DEBIASIThe second point is that it's really the infants that are less than a year of age and particularly those children less than two months of age who suffer the very severe potential consequences of pertussis. Everyone else gets a really long cough, they feel, you know, crummy for six, ten weeks. Some people call this the 100-day cough, but they are not the ones that end up generally not hospitalized, generally not getting pneumonia, not getting their breathing stopping and not having death.

DEBIASISo it's the older individuals who have what they think is a cold or just a bad cough who are perpetuating the transmission. And then it's those young infants who don't yet have the chance to get vaccinated that are at this risk of death. So what's going on now in the 2012 epidemic, which is going on right now, is that at least 37 states have increased amounts of transmission compared to last year. And 18 states have what's over the kind of usual amount that we see in the United States as an average. So we have about 21,000 cases to date up through last week.

DEBIASIAnd the main states that have been affected are Wisconsin, Washington, Montana, also Vermont and Minnesota and Iowa. But if we look across the board we're having increased amounts in the majority of states.

NNAMDIWhat are the symptoms of pertussis and how can you tell if you or your child has it?

DEBIASIIn a very young infant -- so let's talk about school age first. A school-aged child who has a cold that's going beyond 14 days and particularly if there's a persistent cough that's going on more than 14 days, that is when you or your physician should think about pertussis as the possible cause of that illness and in adults, you may not even have as severe symptoms as that. It could be a cold going on and on, but if you -- people have done studies retrospectively for instance of adolescents are adults who have been coughing for longer than two weeks, and if those people are cultured, about 20 percent of them, the reason is pertussis. So it's relatively common when you're getting beyond that two-week mark.

NNAMDIHere's this email we got from Carolyn in northern Va. "Would you, an adult, recognize the symptoms of pertussis? My husband brought home what we thought was a very bad cold. Of course, I caught it. Turns out we both went through a terrible bout of whooping cough. That was last month. We have both had our vaccine updates in the last three years. It's here in northern Va.," says Carolyn.

DEBIASIAbsolutely. So, you know, it is -- pertussis is in every state every year. So that is not what is new. What is new is that the amount of cases has increased. But the point she makes is extremely important. For us it's a nuisance, but if you for instance are a grandparent who's been -- had a cold for two weeks and coughing, you don't realize you have pertussis, but you're holding your new grandchild who is not vaccinated, because you can't even start getting your vaccine until you're two months of age.

DEBIASIThat's really the highest risk population, and that's really why the CDC, really over the last two to three years has studied and made recommendations to expand the recommendations for pertussis revaccination. And there's a new vaccine, relatively new over the last five, six year, the TDAP, which is recommended as the booster now for adolescents and adults so that we are going to prolong the duration of immunity for these older individuals.

NNAMDIGot to take a short break. When we come back we'll continue this conversation. If you have called, stay on the line. We will get to your calls. If the lines are busy, go to our website, kojoshow.org and ask a question or make a comment there. Send email to kojo@wamu.org, or send us a tweet @kojoshow. Have you vaccinated your school age children? If not, why not? I'm Kojo Nnamdi.

NNAMDIWelcome back. Roberta DeBiasi joins us in studio. She's a pediatrician specializing in infectious diseases at Children's National Medical Center. She's also professor of pediatrics add George Washington University. Joining us by phone is Steven Salzberg. He's a professor medicine and biostatistics in the Institute of Genetic Medicine at Johns Hopkins University School of Medicine. You can call us at 800-433-8850. Here is John is Silver Spring, Md. John, you're on the air. Go ahead, please.

JOHNYes. Hi Kojo. I just wanted to comment on Dr. Salzberg's earlier comment about not being supportive or in favor of the research of the...

NNAMDIOf the publication of research.

JOHNRight. Right. The publication of the research of the virulent form of Avian Flu. I'd like to point out that as a result of that research, it was discovered that the wild strain of the flu was only four genetic mutations away from being that kind of virulence and that kind of deadly flu. And if they hadn't done that research, we wouldn't have known that, and we wouldn't be able to take precautions for it.

NNAMDISteven Salzberg?

SALZBERGWell, I've actually heard that argument. The fact is that there's really nothing we can do about the fact that there might be four or five mutations that turn an Avian Flu into a human transmissible flu. And if we want to better prepare ourselves for Avian Flu, we should be putting efforts into a faster way to develop vaccines which, as Dr. DeBiasi mentioned, takes us six to eight months to develop right now. So we're also not increasing our efforts at surveillance of Avian Flu, so although it's a theoretical benefit that you can argue for from those papers, I find it to be a pretty minor one, and the potential harm from those studies is much greater, so that's why I'm pretty strongly opposed to them having even done the work.

NNAMDIJohn, thank you very much for your call. Here is Susie in Northern Va. Susie, your turn.

SUSIEOkay. Can you hear me okay?

NNAMDIYes, we can.

SUSIEOkay. I was just calling to ask a question. I am 63 years old and before the age of one I had whooping cough, so I'm wondering am I candidate that I should be getting the vaccine as an adult vaccine?

DEBIASIYes.

NNAMDIDr. DeBiasi.

DEBIASIYeah. That's an excellent question. So whether you've had natural infection, or you have been vaccinated, we know that immunity wanes, and yes, you would definitely be a recommended -- actually anyone -- so let me just back up and explain how we vaccinate now, and then answer your question.

NNAMDIPlease do.

DEBIASISo, you know, right now it's a recommended standard vaccination for children. We give five doses up to the age of seven. So they'll get a dose at two months, four months, six months of age, a booster at 15 months of age, and then their fifth dose between four and six years of age, and that was our standard immunization scheme. We used to use what was called a whole cell vaccine, so this was when it was first developed. It was actually the actual bacteria that was inactivated, and it worked very well.

DEBIASIIt had very good efficacy. But as we got good at decreasing the number of cases, people then focused more on potential side effects of the vaccine, appropriately, and therefore an acellular vaccine was developed, mean only little parts of the bacteria that we know are important for causing the symptoms and for which you would need immunity was developed. And that's the acellular pertussis vaccine, and that's what we use now. We don't use the whole cell vaccine any more.

DEBIASISo all the children nowadays, and really since 1998 exclusively have gotten the acellular pertussis vaccine, and while it works very well, if you measure immunity right after receiving the vaccine and indeed, you know, a year after you had your fifth dose still very high amounts the immunity are measured. We know that as the years go by, the amount of immunity that you maintain wanes pretty rapidly. So by five years after even the booster dose, we're down to 70 percent protection, which is not good enough when you're in a community to prevent transmission. So absolutely you would be a candidate for the TDAP.

NNAMDIThank you very much for your question, Susie. And should teens and adults get booster shots given the new outbreak? Same advice you've given Susie? Absolutely, Susie. Thank you for your call. Steven Salzberg, some people are worried that the increase in whooping cough corresponds to an increase in the antivaccine movement that urges parents not to have their children vaccinated. Is there any evidence of such a connection?

SALZBERGActually, there's considerable evidence for that. If you look regionally at where the whooping cough outbreaks have occurred, not just this year but over the last five to seven years. There have been clusters of outbreaks in California in particular and Wisconsin and Washington state where there also happened to be strong antivacs communities -- antivaccination groups which are spreading stories which aren't correct, but they nonetheless spread stories and rumors that the vaccine might cause some kind of harm, and actually, their propaganda, and I use that word intentionally, suggests that all the vaccines that are in the childhood schedule might cause some kind of harm including autism, which is most frequently what they claim.

SALZBERGAnd it's important especially this time of year with parents bringing their children back to school, many parents have never really thought about this, especially parents who are sending their kids to preschool or kindergarten for the first time, and that's when you're required to demonstrate your kids have had their shots, and then they -- if they go on the Internet and look up anything at all about vaccination, there's a pretty good chance they're going to find out some misinformation, and they may find out -- they may discover misinformation from the antivaccination movement which will tell them don't get your kids vaccinated.

SALZBERGAnd I want to take this opportunity, and I'm sure Dr. DeBiasi agrees, to just remind people that vaccines have been probably the single greatest public health advance we've had in the last hundred years, and they're incredibly effective at controlling most childhood infectious diseases including whooping cough which we've been discussing, and their effectiveness also depends on having a large number -- a very large percentage of people vaccinating, not only kids, but as we were just discussing, the parents of the kids and the grandparents of the kids should also get booster so that if a case does crop up of whooping cough, or of other diseases that we can control with vaccines, then it won't have a chance to spread because most people would be protected.

SALZBERGSo clusters of -- but back to the original question, the clusters of whooping cough outbreaks often do emerge from children who were not vaccinated because their parents are opposed to vaccination. And one other quick point, the point is often made in comments on some of my articles that well, but what about all these vaccinated children who are getting sick? And that point is made as if that somehow proves that the antivaccination movement has nothing to do with it.

SALZBERGAs I believe Dr. DeBiasi already mentioned, vaccine is not a hundred percent effective. So even if everybody gets vaccinated, we're still going to have 10, 15 percent of people, children who might be susceptible to the viruses or the bacteria that we're vaccinating against. And the best protection for them is to have them surrounded by people who are protected, then they're not going to get infected.

NNAMDIWell, the state of Washington has declared a whooping cough epidemic with 1200 cases in the first five months of the year, the most in at least three decades, and ten times more than the 128 in the same period last year. Why are the numbers so high there?

SALZBERGWell, the -- it's very hard until we've basically collected data for a couple of years after the fact, to answer that definitively, but it is the case -- there was a story in the Seattle Times last years that Washington State parents are choosing not to vaccinate their kindergartners at a higher rate than anywhere else in the country. So I attribute at least part of that increase in Washington State to what seems to be a high number of -- high percentage of parents who are, for whatever reasons, electing not to get their kids vaccinated.

NNAMDIAnd we got an email from Julie, who said, "I'd like to know your opinion on the chickenpox vaccine. My son was in the first wave of children to receive the chickenpox vaccine, and at that time there was no protocol for a booster. I'm not sure if it's recommended now. Then when he was in middle school he contracted what they said was a wild virus and very ill. Understanding that contracting chickenpox as an older male can have significant complications, I felt like it would have been just better to let him get the chickenpox as a toddler. Is there a recommended booster now?" Dr. DeBiasi.

DEBIASIYeah. I think chickenpox is another disease where I think time makes us forget the severity of the complications we saw from chickenpox. So to answer the first part, is it better to get natural infection, the answer is absolutely not. So I can tell you, you know, I can give you CDC data, but I'm going to give you personal data. You know, I've been in infectious diseases for almost 20 years, and when I was younger, we always, every single week, had a child hospitalized with a complication of chicken pox, and by that I mean, if you remember in the media back then the flesh-eating strep infections where they had very severe superinfections of their chickenpox lesions.

DEBIASIThey would lose limbs, and it was very noticeable. I mean, this was something we saw every week. It wasn't an unusual experience. Now that we have chicken pox vaccination, we don't see this anymore, and in fact, some of the younger doctors that I teach have never seen a case of chickenpox. I have to teach them what it looks like when we occasionally have a case. So, you know, the most important answer to your question is no, it's not better to get natural chickenpox.

DEBIASIAs far as the booster, just like with pertussis, when we follow diseases over a long period of time after vaccination, and if we see increases in the number of cases, then we make recommendations after research and proving that the cause of the increase incidence is because of waning immunity. That's when a booster is recommended. So in the case of varicela, there are two shots recommended currently in the childhood vaccination series.

NNAMDIHere is Sarah in Shepherdstown, W. Va. Sarah, you're on the air. Go ahead, please.

SARAHHey Robi, how are you?

DEBIASII'm good. This is one of my friends and physicians in Shepherdstown.

NNAMDIRobi, huh?

SARAHI was calling to see just what is the recommendation for healthy children -- school-age children and adults as far and the flu vaccine? Should we still be getting that every year or not?

DEBIASIYes. So we used to have very hard to remember who should get vaccinated and who shouldn't. Essentially it's now recommended for everyone over six months of age.

SARAHOkay. Thank you very much.

DEBIASIAnd this is my friend Sarah who's not a physician, in case...

NNAMDII was about to say Sarah, do you want to exchange...

SARAHThat's correct.

NNAMDI...recipes something like that.

DEBIASIYes.

NNAMDISarah, thank you very much for your call. We move onto Mae in Washington D.C. Mae, you're on the air. Go ahead, please.

MAEI was calling to ask if there is a timeframe after a toddler has had blood transfusions when it's safe to resume immunizations.

DEBIASIThere's no harm in immunizing someone who's been transfused. The question is, will the vaccine itself be effective. So -- and that is really only a case -- the only scenario where there's an issue with that is in someone who's received a blood product called intravenous immunoglobulin. So this is an antibody preparation that is used for certain treatments of things, and that is a whole bunch of antibodies. So if you think about it, if you give a vaccine into some who has these large amount of circulating antibodies, they won't be able to just make their immune response to the vaccine. So it's not that it's dangerous, it just won't be effective, and that's really only true for the live virus vaccines.

MAEBut what about the antibodies that are present in the blood that's transfused?

DEBIASIWell, it -- there are many types of transfusions, so I'm not sure exactly which one you're referring to, but the most common type of transfusion is for what's called packed red blood cells, and those are solely the red blood cells, so we're not actually transfusing antibodies.

MAEBut this was a toddler who had a severe case of HUS and multiple transfusions.

DEBIASIIf it was packed red blood cells there's no contraindication to vaccinating.

NNAMDIOkay. Thank you very much for your call, Mae. We're just about out of time, but we got an email from Jeannine who said, "My daughter had whooping cough at six weeks old. It was a terrifying experience. At the time I was told she would most likely have asthma or other breathing-related issues. She's seven now, and luckily we have no problems. Are we in the clear for asthma, or is this still an issue?"

DEBIASIThere's no link to my knowledge between and reactive airway disease or asthma long-term. There has been research and mounting data that there may be a link between respiratory syncytial virus, RSV infection, which is different infection of infants, and that being linked with future asthma, but not pertussis.

NNAMDIRobert DeBiasi, she's a pediatrician specializing in infectious diseases at Children's National Medical Center and a professor of pediatrics add George Washington University. Steven Salzberg is a professor medicine and biostatistics in the Institute of Genetic Medicine at Johns Hopkins University School of Medicine.

NNAMDI"The Kojo Nnamdi Show" is produced by Brendan Sweeney, Michael Martinez, Ingalisa Schrobsdorff, and Tayla Burney, with assistance from Kathy Goldgeier and Elizabeth Weinstein. The managing producer is Diane Vogel. Our engineer today is Timmy Olmstead. Natalie Yuravlivker is on the phones. Thank you all for listening. I'm Kojo Nnamdi.