Press Briefing Transcript

CDC Update on H3N2v Cases Telebriefing

Thursday, August 9 at 1:00 PM ET

Operator: Welcome.  I'd like to thank you all for holding.  An inform you that your lines are in listen-only for the conference until the question-and-answer session.  After that you will press star-1 on your touch tone phone.  I would like to turn to tom skinner. 

Tom Skinner: Thank you, Ed.  Thank you all for joining us today for this update on influenza a H3N2 variant virus.  We're having this telebriefing today, because as many of you know, we've had a rise in the number of cases that are -- that have been reported to CDC.  These are -- this increase is the result, and a change somewhat in what constitutes a positive case of H3N2 for surveillance purposes.  And Dr. Joseph Bresee from the CDC is here to help put this into perspective and context for you.  He'll also go over some things we talked about last week in regards to preventive steps people can take to protect themselves, especially those who will be and are attending agricultural fairs.  I've got Dr. Bresee to speak for three to five minutes.  And then we'll open it up for your questions and answers.  So Dr. Bresee. 

Joe Bresee: Thanks, tom.  Hi, everybody, this is Joe Bresee from the influenza division here at the CDC.  Today I’ll provide an update on the status of the investigations into the increased number of reported cases of Influenza A H3N2 variant, or V virus.  As of August 3rd, last Friday, we reported 12 new cases of V virus from three states, Hawaii, Indiana and Ohio.  These 12 cases brought the total number of confirmed cases at that time with this particular virus at 29.  The virus was first detected in July of 2011.  Of these 29 cases, 16 had been reported since July 12th, 2012.  As expected, and as we told you last Friday, additional cases have been reported from areas where cases had been confirmed already, and a case had been reported from an additional state. 

So as of today, there are 145 confirmed cases of influenza infection with H3N2v virus, since the current outbreaks began in July of this year.  This includes one case in Hawaii, one case in Illinois, 113 cases being reported from Indiana, and 30 cases being reported from Ohio.  This is clearly a significant increase since last week's total, so we thought it would be good to try to put this into context.  Like we reported last week, confirmed cases have had exposure to swine, and most of these infections have occurred in people exhibiting swine, family members of exhibiters, people visiting swine barns at fairs, or people attending fairs where swine are present.  The severity of human illness associated with this virus continues to resemble that of seasonal flu.  Most cases are mild and self-limited and resolve on their own.  Most cases have occured in children.  CDC has not received any report of deaths associated with H3N2v infection, and there have been two confirmed hospitalizations with H3N2v infection so far.  Both patients have recovered and have been discharged. 

The next I want to share some information on reporting that Tom mentioned.  On August 6th, which is this last Monday, CDC provided guidance to state laboratories and are now allowing states to confirm their own H3N2v cases prior to laboratory confirmation at CDC.  We've been finding that cases that were positive at the state level were overwhelmingly being confirmed also with CDC.  So given this, and in the context of an outbreak situation with very little seasonal influenza circulating, we felt it was appropriate for states to report positives as confirmed cases rather than waiting for CDC confirmation.  So positive samples will still be forwarded to CDC where they’ll be confirmed by genetic sequencing.  But we anticipate that the change in reporting requirements will provide for a more real-time indication of how these outbreaks are evolving in states.  CDC anticipates that most, if not all, presumptive positives reported by states will be confirmed also at CDC, and we'll keep you posted on that information. 

So for now, CDC will update its case counts every Friday based on information provided by the state partners.  This means that except for Fridays, states will have the most up-to-date information case counts.  This Friday, CDC's Morbidity and Mortality Weekly Report or MMWR will provide an update of number of cases and provide some information on the effectiveness of rapid influenza diagnostic tests in detecting these viruses.  Note that as testing is currently being done in state laboratories, numbers of cases published tomorrow, but CDC may be a bit different from the numbers I give here.  Today and tomorrow, in the MMWR and in the FluView web surveillance site, and H3N2v landing page on the CDC’s website, the case count number you'll see a significant increase in the number of H3N2v positive human cases like I talked about earlier.  This increase is partly based on the changing reporting requirements which I talked to allowing states to confirm their own, but in fact the increase reflects accurately what is going on in the outbreaks. 

Now, for a little context.  CDC understands that people are concerned as to the rapid jump in the number of H3N2 cases compared with last week.  At this point, there's no evidence of sustained efficient human-to-human spread in the community.  Our seasonal influenza systems are active and not shown any sign of increase in influenza activity.  This is not a pandemic situation.  But of course, CDC is continuing to monitor the situation closely, and we'll provide updates frequently.  Right now, a large number of agricultural fairs are ongoing around the country and direct exposure of people to infected pigs has been the primary cause of infections, from investigations conducted so far this year.  So those preventive actions we've been recommending for people who are attending those fairs continue to be as important this week as it was last week. 

In terms of what we can expect going forward based on what we've seen in recent weeks, it’s likely further cases will be identified in the upcoming days.  It's also possible that sporadic infections, even localized outbreaks among people with this virus will occur in other parts of the countries with swine exposure.  There are reports of influenza-like illness from other states, and we're looking into these along with the state health departments.  Finally, limited human-to-human transmission has been observed in the past and we expect some limited human-to-human spread may be observed in these current outbreaks.  Ongoing investigations will determine whether there is, and if so, what the extent of transmission is. 

Again, while the cases so far have been mostly mild, as with seasonal flu, severe illness resulting in hospitalizations have occurred, and even death is possible.  Persons with underlying chronic conditions that place them at increased risk with seasonal influenza are likely also at higher risk for complications from H3N2v infection.  Persons with suspected H3N2v virus infection and at high risk of influenza complications, as well as hospitalized patients with suspected H3N2v infection should be treated with antiviral drugs as soon as possible.  H3N2v virus is sensitive or susceptible to available prescription antiviral drugs, oseltamivir and zanamivir.

Like we said last week, there's guidance to the public, but what we really want to focus on is guidance to folks who will be exposed to pigs, especially in the setting of agricultural fairs.  And the guidance is the same as last week.  Wash your hands frequently with soap and water before and after exposure to the animals.  Never eat or drink or put things in your mouth while in animal areas.  Never bring food or drink into animal areas. If you're at high risk for flu infection like elderly, young children, people with underlying diseases, think about avoiding pig exposure altogether when you go to the fairs.  And finally, avoid close contact with animals that look or act ill when possible.  For anybody, whether you have pig exposure, well, for anybody else, I should say, if you go to a doctor, for flu symptoms following direct or close contact with swine, tell your doctor about the exposure.  If you have flu symptoms, follow the CDC’s regular recommendations for seeking treatment for influenza, and more importantly, follow your doctor's recommendations.  If you've had symptoms of flu or very sick or worried about your illness, contact your health care provider.  They may wish to test you and treat you with an antiviral medication.  That's all I had for now.  And I’m happy to take questions. 

Tom Skinner: Ed, I think we're ready for questions, please. 

Operator: Thank you, sir.  At this time if you'd like to ask a question, please press star 1, ask your question.  You'll be prompted by the automated service to state your name and pronunciation.  One moment, please.  First one comes from Helen Branswell.  Your line is open. 

Helen Branswell: Thank you very much for taking my questions.  Two quick questions.  The first is, when you're looking at the viruses in the lab, do they all look identical?  Are they all this virus with the m gene from the pandemic virus from 2009, and the second is, is there any consideration being given to asking fairs to not hold swine competitions this year in light of what's going on? 

Joe Bresee: Thanks, Helen.  I'll absolutely let you ask two questions.  Thanks for the questions.  The first question is easy.  Yeah, these viruses are all the same.  They're not completely genetically identical, but very close to being so.  All the viruses we've seen so far in the increase in cases are the H3N2v viruses with the m gene as you say.  The second question is a good one, too.  Right now, what we know is that because the confirmed cases that we know about have direct exposure to pigs in these settings, we think we have a good strategy to prevent that transmission.  And it comes from two angles.  One is from the human side, getting people to wash their hands, getting people to not take food and drink or things that would go in their mouth while they're close to the pigs and keeping high-risk people away from the pigs, all make good sense, as well as keeping away from sick pigs.  We think that will go a long way toward avoiding transmission even in the context of holding these swine fairs.  The other angle is the agricultural colleagues from counties and national levels are being very aggressive about screening pigs that go into the fairs, and excluding sick pigs, and we think that will also go a long way to preventing transmission.  So I don't think it's necessary at this point at least to cancel a swine show, like you said.  We'll continue to follow these things, and we'll continue to follow the cases and learn more about the epidemiology and exposures of risks over the coming weeks.  And the recommendations may change.  But I think let's let the prevention strategies that are just now being put in place take hold and see what we get. 

Tom Skinner: Next question, Ed? 

Operator: Next question comes from Erica Edwards, your line is open. 

Erica Edwards: Hi there.  I wanted to clarify something.  To what do you a tribute this large increase over the past week?  Is it just all the fairs happening at this time of year, or more testing, or both? 

Joe Bresee: I think it's a little of both.  I think it's mostly the fairs, though.  This time of the year is when you have county and state fairs in states around the country.  There's thousands of them.  So I think in that setting, there's lots of close exposure between humans and pigs, especially kids.  So I think that accounts for the increased transmission more than anything else.  I think we are doing a better job of being aware of these viruses and testing for these viruses, and certainly county and state health departments have been very good in doing surveillance for these viruses and reporting them when they find them. I think it's a little of both.  But I think as long as there's close contact between sick pigs and humans; we're going to get some of these cases. 

Tom Skinner: Next question, Ed? 

Operator: Mike Stobbe, state your affiliation, please. 

Mike Stobbe: Mike from the AP.  Thank you for taking the question.  I was curious if you could share any more information about the hospitalizations, in what states they occurred, and/or how old and what gender they were, and/or did they have preexisting conditions, or how sick are they?  And as they recovered, are they still in the hospital? 

Joe Bresee: That’s a good question, Mike.  I can't share any specific information about where the cases are, or their ages, et cetera, at this point.  I can tell you that both hospitalizations are over.  They were discharged and are back at home.  But past that, I can't say anything.  I can tell you most of the cases, as you know, are among kids.  So we know that.  But as far as the severe cases are so few, I won't go into details about them. 

Mike Stobbe: How many hospitalizations is that total now? 

Joe Bresee: Two. 

Mike Stobbe: Since the beginning of July 2011? 

Joe Bresee: No, July 2011, we had three last year among the early cases with this virus.  And the additional two.  I think it's important to say that we counted two this year among confirmed cases.  As the investigation proceeds, we fully expect to see more hospitalizations.  And we fully expect that those hospitalizations will be principally among patients with high-risk conditions.  So we really want to get the message out that folks with high-risk conditions try to avoid pig exposure in these settings. 

Tom Skinner: Next question, please? 

Operator: Elizabeth Weise.  Your line is open, ma'am. 

Elizabeth Weise: Hi.  Thanks so much for taking my call.  Two questions.  You said most of the cases are in kids.  What percentage, and how do you define kids?  And since pigs unlike humans don't travel around the country in cars, how are the pigs transmitting it to each other? 

Joe Bresee: That’s a good question.  I don't know if I’ll attack the second question, because I think that's a better question for our USDA colleagues who know much more about pig populations and how they're transported than I do.  I think that -- for the first question, I think we can answer that.  The vast majority of the cases are children.  As I reported last week, I think it was 13 out of the 16 cases we reported last week were among children.  This week, though the numbers may change a little bit, the percentage of cases that are children is going to be over 90%.  And this is actually consistent with what we know about the immunology, or the population, immunity to this virus.  We know children just don't have any experience with viruses like this.  And therefore, probably don't have any protective antibodies and are more susceptible.  Predominantly it's a childhood -- predominance of cases are among children. 

Tom Skinner: Next question, Ed? 

Operator: Next question comes from Caitlin Hagan.  State your affiliation, please. 

Caitlin Hagan: I’m with CNN Medical. Thank you so much for taking my question.  Regarding the confirmed cases, you had said 145 with 113 in Indiana.  I actually just hung up with Dr. Larkin before this briefing who is the head of the Indiana State Health Department who said that as of 10:00 this morning, they had confirmed 120 cases.  I was hoping you could clarify.  Does the 145 confirmed now need to jump to 152, or are you sticking with 113 in Indiana? 

Joe Bresee: That’s a good question.  It points out how fluid this is.  I think states, Indiana, Ohio, are looking for these cases, are continuing to test for these cases.  So what will happen is you'll see is the confirmed case counts from states will continue to rise.  So if they report that, that's what I would go with.  I think that, as I said, previously, we had our current case count at 145.  And I said that may actually change before tomorrow's MMWR comes out.  And it may continue to change maybe on a daily basis.  The states will have the latest data from their states and the CDC will summarize those data each Friday. 

Operator: Next call from Maggie Fox.

Maggie Fox: I’m with NBC News. Can you tell us if there's anything else people can do?  Flu vaccines are arriving in pediatricians' offices.  But clearly vaccination isn't going to help you against this one, right? 

Joe Bresee: That’s right.  It's a very good question, especially as we start into seasonal vaccine program time, which we're in now.  First let me say that, get your flu vaccine.  Everybody should get a flu vaccine this year in the U.S.  Because flu, regular seasonal flu will be here soon, and that will help protect you against that.  But you're right about the fact that the seasonal flu virus likely will not protect you against this virus.  And so -- but we know that most of the cases, or all the cases we have confirmed so far of this virus probably was acquired from direct or indirect contact with swine.  So to prevent seasonal flu, get your vaccine and to prevent your H3N2v cases if you have exposure to swine, do a few of the things we talked about: wash your hands; don't be around sick pigs, et cetera.  There are really two different prevention strategies for two different viruses. 

Maggie Fox: And can I follow up on this?  Have you guys figured out how much is being transmitted from people back to pigs? 

Joe Bresee: That’s a good question, too.  We know that influenza virus, human influenza viruses can occasionally be transmitted to pigs and we've seen that in the past.  We don't have any evidence at this point that humans transmitted this virus back to pigs in recent times.  The USDA conducts a swine influenza surveillance system among swine in the US, and are actively investigating that question, and also the question of how much virus is out there in pig populations. 

Maggie Fox: Thanks. 

Tom Skinner: Next question, Ed? 

Operator: Next question comes from Jon Cohen.  State your affiliation, please? 

Jon Cohen: Science magazine.  Thank you for taking my call.  I wanted to see if you could put this in a little more context.  Every year there are transmissions at fairs from pigs to humans.  How does this differ in terms of numbers?  And how many cases do you not have evidence or indirect contact with pigs?  And are suspected to be human-to-human transmission? 

Joe Bresee: That’s a great question.  Yeah, every year we do get these cases.  And just to give you some context, before 2007 or so, we would hear about one of these cases every year or two years.  Since 2007, when novel influenza A viruses, which include variant viruses became a nationally notifiable disease we've been hearing about more of these cases.  That coincides with the pandemic preparedness initiative which got the right diagnositics into state departments and public health departments hands to use.  We increased the cases up to five or six a year from 2007 to 2010.  Clearly the large number of cases I just told you about that have occurred this summer and the 13 cases that have occurred with this virus before this summer represent a big increase in the normal number of cases that we hear about from this virus.  And so that's what we're seeing now.  We're seeing a big increase.  We think it's a real increase in cases as this virus compared to previous variant virus in the United States. 

Jon Cohen:  What about the human-to-human transmission? 

Joe Bresee: Thanks for reminding me.  I apologize.  So far of the cases that have been investigated from this recent outbreak, and the cases we have good information on, we don't have any confirmed human-to-human transmission.  We do know in 2011, with the initial 12 cases, or so that were reported last year, there were a few cases where who didn't have any obvious swine exposure right before their illness, and we think those patients likely acquired it from ill humans.  We haven't seen that so far.  We expect to see that shortly.  We wouldn't be surprised over the next few weeks we see some of these cases, but so far, all the cases have been involved with close or indirect exposure with swine. 

Operator: Jennifer Delgado.  State your affiliation, please. 

Jennifer Delgado: I’m with the Chicago Tribune. I was just wondering, the public, they might hear these cases jumping.  What is the risk to them?  People in every day, I know we talked about state fairgrounds, what's your message to them in terms that they need to be -- you know, what kind of precautions they should take besides washing hands? 

Joe Bresee: That’s a good question, thanks.  So far, if you're not exposed to pigs, we don't think your risk to this virus is appreciable.  We don't think you need to do anything different than you're doing now.  If you get sick and feel really sick, go to your doctor and your doctor can advise whether you need a flu test or need to be treated.  Because we know so far at least that the overriding risk factor for acquisition of this infection is exposure to pigs that are infected, that's really the risk factor we're looking at, in trying to design prevention messages around.  So for those not exposed to pigs, do what you always do this time of year, or any time of year when you get sick.  Stay home, cover your coughs, and if you feel sick enough, go to your doctor and ask for their advice. 

Tom Skinner: Next question, please, Ed? 

Operator: The next one comes from Dan DeNoon. 

Dan DeNoon: I’m Dan DeNoon with WebMD.  I want to get back to the number of children infected.  Does this suggest that adults may have some residual immunity from previous exposure to H3N2, and if that's true, would vaccination status have any bearing on who gets infected?  Or do you have any information on whether on the immunization status of the children who have been infected? 

Joe Bresee: That information is being collected as we speak.  That's one of the pieces of information that we determine in these outbreak investigations.  You're right, though, the predominance of kids in the early cases we're seeing probably does reflect at least to some extent the immune background of the population, where adults, because they've been exposed to H3 human viruses a lot and potentially vaccines in their lifetime, may have some cross-protective antibodies.  We don’t think that most adults have it but we think some adults might have it.  And the predominance of kids also relates to the exposures at the fairs.  There’s lots of kids at these fairs, they take care of the pigs, bring the pigs, and so we think that the predominance of the kids is probably a combination of who's been exposed to these piss most closely, but also the background immunue levels in the population by age group. 

Dan DeNoon: Can you tell me a little more about the typical exposure to the children in the fairs?  I guess I’m not aware of that. 

Joe Bresee: I wish I could.  I'm probably not an expert on what the kids do at these fairs.  Certainly a lot of kids will bring pigs to show them that they've raised and spend lots of times in the pig barns with their pigs. 

Dan DeNoon: Thank you. 

Operator: Next question from Roseanne Matas.  State your affiliation, please. 

Roseanne Matas:  I’m with the CBS station in Chicago.  You've answered most of my questions.  But can this be spread from animal to animal, and should people be concerned about any other animals at fairs? 

Joe Bresee: That’s a good question.  It can certainly be transferred from pig to pig.  Like all flu viruses, swine flu viruses or avian flu viruses or human flu viruses, they tend to be well adapted for whatever species they infect.  Human viruses tend to infect humans and rarely other animals, and same with swine and avian viruses.  I guess it's theoretically possible for that to happen, but it’s pretty unlikely. 

Tom Skinner: Next question, please? 

Operator: Next question from Mark Crane.  State your affiliation. 

Mark Crane: Medscape Medical News.  I wonder if you could just go over the numbers again so I’m clear about that.  145 cases, is since what date and in which states, if you can go over that again? 

Joe Bresee: Happy to.  The 145 cases are cases that have occurred since July 12th when the first case in Hawaii was reported.  And so by state, those 145 cases are comprised of one case in Hawaii, one case in Illinois, 113 cases in Indiana, and 30 cases in Ohio.  As we heard, those case numbers may change fairly rapidly as we heard from Indiana.  But that's what we have so far. 

Mark Crane: Thank you. 

Tom Skinner: One more question, please.  And then we'll conclude after that. 

Operator: Our next question will come from Michael Locklear.  Your line is open. 

Michael Locklear: This is WOUB News.   I just had a quick question about the numbers again.  You said there was a significant increase in the virus.  Are you talking about from last week to this week, or do you expect a jump in tomorrow's report? 

Joe Bresee: What I meant when I said that was last week's total to this week's total, I think we may see additional cases reported in tomorrow's report.  I don't know.  But certainly testing is ongoing now, or is ongoing overnight.  We'll try to add those cases to tomorrow's report.  But more importantly, I think we expect to see increasing numbers of cases next week as well, probably as exposure continues a little bit, and as the prevention measures are put in place. 

Tom Skinner: This concludes our call.  I want to thank everyone for joining us.  I want to remind all of our reporters on the line of a plan moving forward to keep you up to date on case counts.  Again, we'll be updating our case counts every Friday.  You know, starting tomorrow.  So if you really do want up-to-date information beyond what we release on Friday, you're going to have to get that from the states.  But our plan moving forward is to update these case counts once a week, starting tomorrow.  So we'll keep you informed, as we go along.  If you have any further questions today, you can call the CDC main press office at 404-639-3286.  And thank you once again for joining us. 

Operator: At this time now, we conclude this conference.  You may disconnect.  Thank you for your attendance.

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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES