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Press Briefing Transcripts

CDC Telebriefing on Investigation of Human Cases of H1N1 Flu

May 11, 2009, 1 p.m. ET

  • Audio recording (MPEG) MP3 audio file

Dave Daigle: Hi, actually this is Dave Daigle from CDC Media Relations.  And today, Dr. Anne Schuchat from CDC’s National Center for Immunization and Respiratory Diseases will update us on the novel H1N1 outbreak. 

Anne Schuchat: Good afternoon.  You know, I think this issue has been fading a little bit from the media, and I want to give you a sense of where we're at here at CDC.  At CDC we're working on transitioning from identifying and understanding initial cases to a comprehensive longer term perspective.

There's much to be done moving forward with an eye towards what will happen in the southern hemisphere and preparing for the fall here in the northern hemisphere.  Currently, there are 116 CDC staff deployed in the field supporting outbreak response activities.  Many of those efforts involve field investigations that are designed to strengthen our knowledge about how well this new virus is spreading, who is most at risk for illness, how effective prevention measures are, antiviral treatment and so forth. 

We're trying to build a strong foundation for understanding the spread of the virus by establishing lab diagnostic testing capability nationwide and throughout the world.  As of today, all of the states have diagnostic test kits. Eleven are confirming their own specimens and eight additional states will soon be confirming their own specimens.  We've also shipped diagnostic test kits around the world and labs in most countries in the world will have them soon. 

As we mentioned, the vaccine development process is under way with the very first step involved in vaccine planning being preparation of a candidate virus, a virus that can be a candidate for vaccine development.  CDC has sent five different virus isolates to eight different labs around the world and those laboratories will help us evaluate which virus isolate would be best to develop into a vaccine.  We've issued a number of interim guidelines and we're at the point in the response where we are actively reviewing the guidance we've issued in light of what we've been learning to see whether changes or amendments to guidance will be appropriate. 

The scientific community is also continuing efforts to understand the origin of the virus and to track changes in the virus that may occur over time as we go forward.  Our laboratory here at CDC is receiving about 300 to 400 specimens a day and for the priority specimens, we're able to provide results in less than 24 hours.  Some specimens from late April still do await confirmation, but we understand now that few of the states continue to have significant backlogs.  We believe we're being able to work cooperatively with the state to assure that processing goes forward.  Soon, some states may reach a point where it will become impossible to count individual cases and at that point they'll be transitioning to reporting systems that we use for seasonal influenza where we don't actually count individual cases. 

At CDC we'll continue to update the individual case counts for as long as possible, but we're also beginning to share with you our surveillance systems that we use for seasonal flu so that we can get a sense—or communicate a sense of the trends over time.  As you know, we've been updating our website at 11:00 a.m. each day with a new case count.  I want to mention that today we're doing a correction on the website because of a little bit of an error; so that today's numbers there are 3,300 probable and confirmed cases in 46 states and the District of Columbia.  That's actually a little bit lower than previously because we've been able to rule out some of the probable cases.  The confirmed case count is 2,600 in 43 states and the District of Columbia.  The most recent onset is May 5th and there are three known fatalities here in the United States with 94 confirmed cases that required hospitalization so far as we know as of today.  Our hospitalizations and cases continue to occur in younger persons, the median age of cases is 15 years and 62 percent of the confirmed cases are under 18.  Of course, the WHO is updating their numbers and as of this morning, they're reporting 4,694 confirmed cases in 30 countries with the first confirmed case in China being reported. 

I want to put the confirmed and suspect case information into context.  As we've been saying, these actual numbers need to really be interpreted with caution.  They tell us for sure that this virus is circulating throughout the United States and it is likely that it's found in every state even though we don't have confirmations in every single state so far.  The numbers tell us that more people have become ill and more are likely to become ill, but we continue to see that most people who are becoming ill with this virus tend to recover in a way that's similar to what we see with seasonal flu: some fatalities, some hospitalizations, but the vast majority recovering from their illness.  Another note of caution is that many states did not report over the weekend and so we expect there to be a big jump in cases tomorrow.  That doesn't mean that there was a big jump in the onset of cases, but these are the cases that are getting officially reported or confirmed.  We do think the numbers we're telling you are underestimates of how many people are actually infected.

There's less need for the diagnostic testing as we've understood more and more about this virus, just as in seasonal influenza.  The vast majority of people don't actually get a laboratory confirmation.  So putting the numbers in context, the numbers that each state is confirming is affected by the number of people who go in for testing and the processes and policies that the states use in confirming those test results as well as the stability of what's really going in terms of disease trend.  On our website and going forward, we're going to be sharing with you a way to track the novel influenza A virus activity consistent with the way we track seasonal flu, using our FluView system.  This is available on our web site today, and it will show week by week what's going on.  As of the May 8th FluView, we did find that a number of people visiting their doctors or healthcare providers with influenza-like illness is higher than expected in the U.S. for this time of year.  You'll be able to see an increase or uptick in that statistic on the grass on the FluView.  We also have data that shows that seasonal influenza viruses are continuing to circulate in the U.S., but this novel H1N1 virus as well as the unsubtypable viruses now do account for a significant number of the viruses we're detecting.  It's about 40 percent of the past week's viruses that were this H1N1 virus, but we do see many strains that are other, regular seasonal flu viruses. 

I think there's a perception out there that we're winding down, that we're in a lull.  It's a time when we really need to guard against complacency as we move into a new normal.  We than this virus is present in our communities and it's actively circulating and we don't know what will happen come the fall.  New theories are being offered in many areas and it's going to be important for science to move forward and evaluate those theories and just remember that we're-- we really think it's important to remain vigilant for what this new virus will do in our population, in the southern hemisphere as well as in the U.S. this fall; and we're taking aggressive steps to have good information to inform policies moving forward. So, I'd like to take questions at this point. 

Dave Daigle: Thank you, Anne.  First question, please, operator. 

Operator: Our first question is from Maggie Fox of Reuters.  Your line is open.  You may go ahead. 

Maggie Fox: Hi, Dr. Schuchat, I know it's just come out, but have you seen the new report in Science from the WHO collaborating group looking at epidemiology and some of the genetics of the new H1N1? 

Anne Schuchat: Actually, I don't think I've actually seen the full report.  Is this - I think we're part of that report here at CDC.  Right?  Yeah.  I think my comment would be that the scientific community has been aggressively moving to understand this new virus and it's been a good collaboration across the WHO collaborating laboratories.  I haven't read the final paper, but I was aware it was going to be coming out. 

Dave Daigle: Thank you, Maggie.  Next question, please, operator. 

Operator: The next is from Elizabeth Weise, USA Today, your line is open. 

Elizabeth Weise: Hi. Thanks for taking my question.  I have two quick questions.  The first one is looking at that Science Express paper they seem to-- they are certainly leaving open a door that there may be a residual immunity among older people because of potential previous exposures to H1N1.

And my second question is- I was out of the flu bubble this weekend and actually talking to regular people again and what I kept hearing from people is “well, didn't they overreact, didn't they overreact”, and I'm wondering how different has the response to this outbreak been?  How much of this is because it's happening in real time or is that actually different from SARS or from Avian Influenza?  I'm trying to get a sense of how this outbreak has been different from previous ones and how that has changed the way that we've reacted. 

Anne Schuchat: The question of residual immunity is a very important one and one that we would love to nail down because it would mean that an important proportion of the population may not be at risk for this new virus.  We don't have definitive information but there are a number of studies that are trying to get at that, both laboratory studies and then epidemiological studies.  As you know, we do have reported cases as old as I think 81 years of age at this point.  So we know that or actually now it's up to 86 years of age in terms of our confirmed cases.  So we know that it's possible for laboratory confirmed disease to occur in seniors, but I think that issue has been an important one from the beginning. 

You know, the question of overreacting is legitimate.  What I would say is that some things have changed since the 2003 SARS epidemic and an important one out of the international health regulations.  With this global cooperation and the IHR, we are committed as a global community to report and share information promptly on public health events of international concern.  Here in the U.S. our government has invested quite a few resources in strengthening our preparedness for pandemic influenza and those resources helped us have stronger surveillance systems and new laboratory tests that helped us detect the problem in the U.S.  more rapidly than I think we would have otherwise.  So what I would say is that we don't want to have widespread international circulation of a new virus and find out about it months or years later.  By rapid detection, we can get a leg up on prevention through things like vaccine production, should that be necessary.  So I do think the global community is strengthened through the IHR and through the lessons learned from SARS and that here in the U.S. we're greatly strengthened from the investments in our preparedness enterprise. 

Dave Daigle: Thank you, Elizabeth.  Next question, please, operator. 

Operator: The next is from Mike Stobbe, the Associated Press.  Your line is open. 

Mike Stobbe: Hi, thanks for taking the call.  Doctor, first of all, earlier you said the confirmed and unsubtypable now account for about 40 percent of the past week's viruses.  When you said past week do you mean the week that just ended, the seven-day period, and then I have another one. 

Anne Schuchat: Yeah.  On the FluView, you'll see the influenza-like illness graphic and I believe it's the week of-- which week is that?  Sorry.  I think it's week 17 which is--which has the uptick. 

Mike Stobbe: Last week? 

Dave Daigle: Yea, Mike, I’ll follow up for you on that.

Anne Schuchat: I will check on which day. I thought it was the week of the 8th but on this graph I’m looking at, it doesn't say that.  So, we'll have to double check.  We don’t have- Basically, we're seeing an increase in the ILI illness in our sentinel providers and we don't have today's data yet but the data that's shared in the website does have this increase.  As I said, maybe I haven't said it today, there's a lag between the -- when a case occurs, when a person seeks medical care, when a laboratory test is carried out and when confirmatory information is collected.  So, our epidemic curves do have a lag.  It may look on some of our curves like cases are going down, but that primarily is because of this delay in between when illness occurs and when we know about it for sure.  We haven't seen a dropping off in cases here in the U.S. and I think that is something we're looking toward in the future. 

Dave Daigle: Mike, you had a second part? 

Mike Stobbe: Yes, sir, thanks.  The Science article that was referenced earlier, the authors estimated that between 6,000 and 32,000 infections has occurred in Mexico as of April 30th.  They tried to give a better feel for the actual impact going on in Mexico.  Do you have a good ballpark estimate?  You've been listing confirmed and probable.  But, how many infections do we really think are out there in the United States right now? 

Anne Schuchat: I think the cases that we're confirming are the tip of the iceberg here.  We have really focused in many of the states in confirming the more serious cases, making sure that cases sought medical attention who had more severe illness, trying to avoid really clogging up the outpatient clinics or the emergency rooms.  We know with seasonal influenza that there's a range between needing to stay home a few days because of high fever and muscle aches and cough to really severe illness requiring hospitalization.  So I believe that the numbers we're reporting are a minority of the actual infections that are occurring in the country, but the way that we're tracking this we will be able to look at increases and peak and decreases.  It's very important that we track the actual virus in a subset of patients and that's what our ILI net or sentinel providers will be doing, putting into context how much of what we're seeing is this new virus versus the seasonal flu strain.  That will be really important in the fall where seasonal flu is likely to be increasing.  Differentiating this new virus from the regular flu strains will be very important.  It's also something that will be a priority in the southern hemisphere to understand whether this new virus is taking hold or just fizzling out and whether the new virus is changing its characteristics, becoming resistant to the antiviral drugs or even changing it’s antigenic or immunologic properties, so that if a vaccine were directed against it, that would need to be adjusted. 

Dave Daigle: Thanks, Mike.  Next question, please, operator. 

Operator: The next is from Alan Miranda from Excelsior.  Your line is open. 

Alan Miranda: Hi, ma'am.  Thank you for taking my question, and I would like to follow up on that-- on that topic about the backlog.  You mentioned that these number of cases might just be the tip of the iceberg, but do you believe that there are also deaths that have not been reported up to this point? 

Anne Schuchat: You know, that's a good question.  Certainly many deaths occur without a specific diagnosis or a specific etiologic diagnosis.  With seasonal influenza we do believe that there are many deaths that are linked with influenza that present as cardiac problems or respiratory problems and one of our regular seasonal influenza tracking systems looks at pneumonia and influenza mortality.  We're looking at that week by week and we don't see an increase in that over the expected baseline.  That's one of the systems that we'll be tracking going forward that will help us know whether a new virus such as this one is having a substantial impact beyond what we're testing with the virologic study, so, for instance in the 1918 major pandemic, you will see a change in the pneumonia and influenza mortality surveillance above baseline and we're not seeing that change right now.  So there may be some deaths that have occurred attributed to this virus that never got a specific diagnosis, but I don't believe so far here in the U.S. we have so many of them that they are of public health concern. 

Dave Daigle: Thanks, Alan.  Next question, please, operator. 

Operator: The next is from Fred Mogul, WNYC.  Your line is open. 

Fred Mogul: Yes, hello, Dr. Schuchat.  It's sort of a perennial and general question and concern in a way, but perhaps highlighted by the recent outbreak of H1N1 which is to say doctors prescribing, you know, antibiotics much of the year and in this case, antivirals and big rushes reported on pharmacies for Tamiflu.  The CDC, obviously, has been issuing guidelines and for many, many years has been trying to discourage this kind of behavior among physicians.  I just wonder what you can say about past and current campaigns on that front. 

Anne Schuchat: You know, appropriate use of antibiotics and antiviral drugs is important.  We want the medicines that we have to work when we need them and overuse or abuse of these medicines can contribute to resistance developing in some of the microbes.  With the antiviral drugs that have been developed for influenza, the focus right now is on use and treatment and our guidance for this interim time, the H1N1 interim guidance focuses on treatment in persons who are presenting with severe illness or people with underlying medical conditions who might be at risk for a worst time with influenza, so, yes, we do think these are wonderful drugs to use appropriately, but the inappropriate use can contribute to resistance and to them not working when we really need them to. 

Dave Daigle: Thank you, Fred.  Next question, please, operator. 

Operator: The next is Betsy McKay, Wall Street Journal.  Your line is open. 

Betsy McKay: Thank you very much.  Dr. Schuchat, a couple of questions.  You mentioned that one of the things you're going to be watching for is whether this fizzles out.  You know, we've certainly seen viruses fizzle out in the past.  I’m wondering if you could talk a little bit about what that would mean?  If it fizzles out, does that mean- in the southern hemisphere, does that mean it is unlikely to emerge in the fall and so forth.  My second question was two congressmen—Georgia congressmen- who were both physicians said recently they don't believe an H1N1 vaccine would be a worthwhile expense for taxpayers.  I’m just wondering if you could comment on that.  Do you believe a vaccine would be worthwhile? 

Anne Schuchat: Thank you.  The issue of the southern hemisphere is very important, but it's also important to remember that influenza viruses are unpredictable and so while I think that finding trends in the southern hemisphere can decrease the uncertainty that we have about what will happen in the northern hemisphere in the fall, we will still be in a situation where some uncertainty persists, so I think the focus is on reducing uncertainty, but recognizing that influenza can be unpredictable. 

The issue of worthwhile investments going forward is a very important one at a time when our budget is constrained.  For several years we've been carrying out pandemic preparedness planning, looking at best case and worst case scenarios, understanding the economic impact as well as the health and social impact that a true pandemic could have.  It's clear that we have a novel virus circulating in the United States and in some other countries as well that we don't have general population immunity that can cause a range of illness from mild to severe, at this point similar to seasonal influenza.  The ultimate impact that that virus could have going forward is less easy to predict.  I think the ideas of investing in the initial steps in vaccine development, which need to be taken months in advance of actually getting a vaccine, are very prudent at this point as we do for any new influenza virus, and I think that the debate about the appropriateness in investments is one that will go forward.  

Dave Daigle: Thanks very much, Betsy.  Next question, please, operator. 

Operator:  The next is from Robert Bazell, NBC news.  Your line is open. 

Robert Bazell: Hi, thank you very much.  Maybe I missed something over the weekend, but you mentioned a third death.  Is that new information and if it is new information, can you tell us as much as you can?  What state, age, underlying medical condition and that sort of thing?  Thank you.

Anne Schuchat: There have been three deaths in the United States associated with this outbreak.  Two of them occurred in Texas and the third occurred in Washington State.  For details about the case in Washington State which was reported over the weekend, I would encourage you to contact the Washington State Health Department. 

Dave Daigle: Thanks, Bob.  Next question, please, operator. 

Operator: The next is from Megha Satynanbrayana from the Detroit Free Press.  Your line is open. 

Megha Satynanbrayana: Hi. I’m wondering if there is any thought on whether or not states should increase the number of sentinel sites that they use in the fall to account for maybe the extra work in tracking two groups of virus? 

Anne Schuchat: You know, the surveillance systems going forward are a focus of our attention.  One aspect that we're focusing on is increasing the viral testing that occurs in our sentinel provider sites.  We do have a very large number of sentinel sites that have been participating over the past few years and we've expanded the number of sentinels in the last few years, so based on the investments in the pandemic preparedness in recognition that we needed a good, geographic representation.  These are active discussions in conjunction with public health authorities in local and state areas, really honing in on what are the best ways to track this virus in the context of seasonal flu.  As you'll see on the FluView site, we have several different systems that provide complimentary information including clinical characteristics, frequency and onset in the community and then of course, the virologic circumstances. 

Dave Daigle: Thanks very much.  And, I am told that's our last question.  So we will send out both a media advisory and we'll e-mail folks via our distribution on the next update.  Thanks again. 




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