Press Briefing Transcripts

CDC Telebriefing on Investigation of Human Cases of H1N1 Flu

May 12, 2009, 12:30 p.m. ET

• Audio recording (MPEG)

Operator: Welcome, and thank you all for standing by.  At this time, I would like to remind parties in your lines are in a listen-only mode until the question-and-answer session, at which time, press star one to ask a question.  Today’s call is being recorded.  If you have any objections, you may disconnect at this time.  I'll now turn the meeting over to Tom Skinner, you may begin.

Tom Skinner: Thank you for joining us for the update of an investigation into a novel strain of H1N1.  With us today is Dr. Anne Schuchat.  That is spelled A-N-N-E.  Last name is S-C-H-U-C-H-A-T.  She is the Interim Deputy Director for Science and Public Health program here at CDC.  She's going to be providing some opening comments and then we'll turn it over to reporters for Q&A.  So, Dr. Schuchat? 

Anne Schuchat: Great.  Good afternoon, everyone.  What I want to do is give you a quick situation update; talk little bit in more detail about a clinical group of patients, and then make some closing comments about where I think we are in this investigation. 

So, as of today, there are about 3,600 probable and confirmed cases in 46 states and the District of Columbia.  We have 3,002 confirmed cases in 44 states and D.C., with the most recent onset May 5th.  As you know, there have been three reported fatalities confirmed to be due to the H1N1 virus.  We have 116 hospitalizations that are being investigated at this point.  Most of those have been confirmed to be due to the H1N1 virus.  Our median age remains low at 15 years with a range, though, of 1 month of age up to 86 years.  Almost two-thirds of our confirmed cases are under 18.  Around the world, the case counts are continuing to increase.  There's a total of 5,251 confirmed cases according to the World Health Organization, and those are occurring in 30 countries with Canada being and the United Kingdom having the largest number of confirmed cases after the U.S. and Mexico. 

In terms of our U.S. situation, you know we've had a active response with more than 100 field staff deployed to help with investigations in this country and Mexico.  We've deployed the test kits to the states, and I'm happy to report that as of today, 29 of the states are now doing their own confirmatory testing for the novel H1N1 strain.  We've sent the lab kits to a number of countries around the world, and testing is a critical part of understanding the situation around the world.  As we continue to investigate, we learn more and we want to share information as we get it. 

I wanted to say a few words today about this novel H1N1 influenza virus and pregnancy.  As many of you know, pregnant women are at higher risk of complications of influenza, whether it's the seasonal influenza or pandemics of the past.  We are also seeing some severe complications among pregnant women in this year's novel H1N1 virus problem, and I really want to make you aware of that, because I think it's something that can have important clinical benefit.  We have about 20 cases under investigation right now where the H1N1 virus has been found in association with pregnancy.  We're continuing to understand the illness in these patients, and a few of the patients have had severe complications.  As I think many of you know there was one fatality in a pregnant woman.  Influenza can cause worse complications in pregnancy than in people who are not pregnant.  Important complications include pneumonia and dehydration as well as complications for the newborn, like premature labor.  We think it's very important when doctors are caring for pregnant women who they suspect may have influenza, that they issue prompt treatment with antiviral medicines.  Sometimes, physicians are reluctant to treat pregnant women with medicines, and sometimes pregnant women are reluctant to take medicines because, of course, they are sometimes risky during pregnancy.  The experts who have looked into this situation really strongly say that the benefits of using antiviral drugs to treat influenza in a pregnant woman outweigh the theoretical concerns about the drugs.  We think that either of the two medicines that this virus is susceptible to it be used for this condition.  So, while we don't have lots and lots of experience yet with this H1N1 virus in pregnancy, it's important to know, to look back on what we do know about seasonal influenza and pregnancy.  We strongly recommend pregnant women receive the seasonal flu vaccine to protect them from complications of influenza during pregnancy.  And for this novel H1N1 virus, we really want to get the word out about the likely benefits of prompt antiviral treatment in pregnancy when you're suspecting influenza.  We are going to be issuing an MMWR report with some clinical and some data about the pregnancy cases that we've been investigating, and I think I would look for that to come out fairly soon with a little bit more detail than what I've shared. 

Yesterday at the media briefing, a few of you had questions about a recent article that came out in "Science Express."  I think it came out two minutes before the press conference yesterday, so I wasn't fully prepared, but I wanted to make a couple comments about this.  It's an article by Christoph Frasier and colleagues called "Pandemic Potential of a Strain of Influenza: H1N1 Early Findings."  This was a modeling analysis looking at data from Mexico in collaboration with investigators there.  And I think it's very important that the infectious disease modeling community is aggressively responding to this novel virus and trying to share lessons learned in real time.  It's important to say that uncertainty remains, that we're learning more about transmissibility and attack rates.  In the article, the authors concluded that the virus characteristics in Mexico were not of the severity or transmissibility that we had seen in the 1918 pandemic, but they compared it with something of a magnitude of the 1957 pandemic.  It's important to say that we may see changes as this virus is present in different countries, depending on the health care resources of the countries and the types of interventions that are carried out as well as potential changes that the virus goes through, as influenza viruses can mutate and evolve in the course of their spread.  So, I think this was an important report, and I applaud the authors for taking on this topic, and we hope that the international community will continue to collaborate to learn as much as we can about this new virus and how it behaves in large populations. 

I also want to comment about seasonal influenza.  We have been mentioning, and on our website, you see that we have cases of the regular seasonal flu strains, the seasonal A-H1N1, the seasonal A- H3N2 (Editor’s note – this is a correction), and the seasonal B viruses.  They are continuing to circulate now at a time when this novel H1N1 virus is also circulating.  One thing you can see from our flu view on the website is that there is an uptick of these other viruses in addition to the H1N1 virus.  We don't think that there was a decrease in seasonal flu and then an increase in seasonal flu.  We think that pattern suggests that more people with influenza-like symptoms are being tested and more of those viruses are being studied so that our efforts to respond to this outbreak have led to recognition of more seasonal influenza.  It's important to say that a large proportion of the strains currently being tested are due to this novel H1N1 virus, but there are other strains circulating.  So, that's an important occurrence.  It maybe foreshadows what we have to face next fall, when seasonal strains of influenza are likely to circulate, and we may see this H1N1 strain come back, perhaps, in worse or milder form. 

The last comment is just to continue to say that vaccine development efforts have been of interest.  This is the time when we are growing up isolates to potentially identify a candidate virus that would be handed off to manufacturers to work on manufacturing or development stages.  CDC has sent five isolates to several different institutions around the world where candidate vaccines, viruses could be developed.  And there are active discussions being carried out across the U.S. government, including with manufacturers, to understand next steps and potential vaccine development and manufacturing.  So, in closing my prepared remarks, I just want to say that I think we are transitioning to the long view now.  We have a focus on the southern hemisphere, where illness may be on the upswing soon, and where we hope to learn as much as possible to help them respond and also to learn for what might be the case here in the northern hemisphere next year.  We're also preparing for the fall, including exploration of vaccine development and manufacturing discussions.  We're also trying to learn as much as we can from the experience of the past few weeks so that we can be better prepared going forward.  So, with that, I'd like to answer questions that you might have. 

Tom Skinner: First question, Rose? 

Operator: Our first question is from Elizabeth Weise, USA Today.  Your line is open.

Elizabeth Weise: Hi, thank you for taking my question.  I wanted to go back to your focus on pregnant women and the specific problems they face.  You said you have about 20.  Do you have any sense of percentages, about what percentage of pregnant women might be at risk for this?  Is pregnancy in and of itself the main, underlying condition, or is it pregnant women who also have other underlying conditions as well? 

Anne Schuchat: Pregnancy is a well-documented risk factor for complications of influenza.  It's not that we think pregnant women get influenza, seasonal flu, for instance, more than other people, but we think when they suffer an infection with influenza, they can have a worse time.  For instance, they may develop pneumonia, they may develop dehydration, and their metabolic system may not be able to handle the infection as well.  So, there are a number of reasons that pregnant women can have a worse time, including some complications, such as preterm labor and complications for the newborn.  So, this is a group that we include among our populations at higher risk for influenza complications, and that's why for the past several years we've been strongly recommending women who are pregnant receive the influenza vaccine, to protect them and to have a better outcome of their pregnancy. 

Elizabeth Weise: Follow-up question.  Is there then the sense that this H1N1 novel influenza is any worse or better than seasonal flu when it comes to pregnant women, or is it just you're trying to reiterate to women that they shouldn't be afraid to take antivirals and to see a doctor if they get it? 

Anne Schuchat: You know, I think that the H1N1 virus that we're dealing with is novel, and so, we don't think pregnant women have ever seen this before or would be protected from it from years past.  Many years with seasonal flu strains circulating, a lot of pregnant women may have some immunity to the strands that are circulating.  We still think vaccination's a good idea for pregnant women, but I think because of this -- because this H1N1 virus is targeting younger people and because it's totally new and because we know that pregnancy is a risk factor for worse complications, we really want to focus our attention on it and make sure that pregnant women and their health care providers have this concern in mind.  Next question? 

Operator: The next is from Jennifer Corbett, Dow Jones.  Your lone is open.

Jennifer Corbett: Yeah, hi.  I have two questions.  The one -- do you recommend for seasonal flu that women, pregnant women, take antivirals or is this specific to the H1N1?  And then the other question I had is at the top you mentioned that there's been a death of a pregnant woman.  Was that one of the women in Texas?  Was she the one in Texas? 

Anne Schuchat: That's right about the fatality we do think that when influenza occurs in pregnancy, it should be treated with antivirals.  The message today, the time of year we're at right now, the majority of what we're seeing that is influenza-like illness, or half of what we're seeing is this H1N1 strain, so it's in this circumstance that we're really trying to remind people that treatment of influenza-like illness in pregnancy is appropriate.  We don't know as much as we would like to know about the H1N1 virus that we're seeing.  And certainly, every day we're learning little bit more.  As we've accumulated some experience with this illness, we are trying to share clinical, interim clinical recommendations.  So, I think that things could change as we get further along in the investigation, but so far, of course, one of our three fatalities was a very sad story in a woman who was pregnant.  Next question, please? 

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

Mike Stobbe: Hi, thanks for taking the call.  Doctor, that "Science" article had an estimate about when the virus might have first appeared.  Can you tell us, you know, as this has been going on, what's science telling you at this point about when it first appeared?  Did it first appear in a pig?  Who infected who?  Do you have any update on that?  And I have a second question. 

Anne Schuchat: Yeah, the paper in "Science" talked about beginning -- there's a virus emerging in the middle of February, and I think the working hypotheses for much of the influenza community right now is that this strain was circulating in pigs somewhere, and eventually, you know, reassorted and was able to infect humans easier, the people got it and then it became easily transmitted between people.  That's a working hypothesis, but of course, the scientific community and CDC included is very open to other hypotheses.  We don't have new information about the specific origins.  We think that's an important investigation that the scientific and public health community is taking on, but so, the clinical illness -- that paper suggested mid-February, and we don't have reason to believe that humans were having a large problem with this before that.  But of course, you know, investigations are active in a number of places. 

Mike Stobbe: Okay.  My second question -- we've begun to see announcements from companies about the availability of commercial tests for this novel virus coming online.  Can you assess those for me?  Are those good tests?  Are they solid?  Are they starting to contribute to the case counts? 

Anne Schuchat: I won't -- I don't have the information to be able to answer the question.  I'm sorry.  I think that it's -- you know, we have disseminated information on sequence and the primers and probes that can be used to identify this virus.  We've also distributed agents and test kits for the public health laboratory network to be able to recognize this.  It's very possible for manufacturers, biotech companies, to make kits that would work similarly to the ones the CDC has distributed.  There's usually a validation process that goes forward, and I'm not -- I don't know whether there's any systemic evaluation of the commercially produced kits that -- I don't know if CDC's involved in any of that.  So, sorry about that.

Tom Skinner: Next question, Rose.

Operator: The next is from Michael Smith, Med Page Today.  Your line is open.

Michael Smith: Dr. Schuchat, you talked about antivirals in connection with pregnant women.  On the Hubra press conference earlier today, they said that antivirals are being aggressively used in Europe, where they're mainly employee cases, and were being reserved really largely for serious cases in the U.S. and Mexico.  Can you comment on how antivirals are being used in the U.S.? 

Anne Schuchat: Yes, that's right.  The circumstances in the U.S. are very different from the circumstances in a number of European countries.  We have this virus in every -- pretty much, almost every state in the country, and suspected it's likely already to the states that haven't confirmed it yet.  We don't have a situation where we can contain the virus's geographic distribution, and our focus is on reducing illness and death and mitigating the impact that this virus has as well as focusing our efforts on areas where they can have the most impact.  So, the priority here is for antiviral drugs for treatment of influenza, where we think the treatment will make a difference, and that's for people with severe illness presentation or for people who have underlying medical conditions or pregnancy, where the complications of an influenza infection might be worse than in other people.  So, our focus for antiviral drugs is primarily on treatment.  And we are aware that there are some other countries where there's a lot of preventive use of antiviral drugs around the traveler, around the first case that they've seen.  That circumstance is not likely to have a benefit here in the United States based on the transmission patterns we're seeing and the stage of the outbreak that was present by the time we recognized this virus.  Did you have a follow-up question, or --

Michael Smith: No, that's good.  Thank you. 

Anne Schuchat: Okay.  Is there another question? 

Operator: The next is from Emma Hitt, Medscape, your line is open.

Emma Hitt: Yes, hi, thank you for taking my question.  You talk about the novel H1N1 virus coming back during the fall.  Is that a certainty?  And will it definitely pick up back in the fall?  And also, do you expect the H1N1 virus to be more robust during the summer months than the seasonal flu strain? 

Anne Schuchat: We wish that we knew what was going to happen in the fall.  Influenza is usually seasonal, and usually, there is very limited circulation in the northern hemisphere during our summer months.  But there is increased circulation in the southern hemisphere during that same time period.  We don't know whether the novel H1N1 virus will circulate in the U.S. next fall, and if it circulates, whether it will be more severe, of similar severity or less severe than now.  We think that if we have good information coming from the southern hemisphere and we see a lot of disease or severe disease associated with this virus, that that would increase the likelihood that we would continue to see problems in the fall.  But we, unfortunately, cannot predict.  The other thing is that these viruses continue to change.  Because we have seasonal influenza strains, including an H1N1 strain that is resistant to oseltamivir and zinamivir.  But because we have an H1N1 strain that's circulating that's resistant and we have this novel H1N1 strain, we also don't know whether there might be a reassortment between the human seasonal flu strain and the novel strain.  So, there's a lot of unknowns, a lot of uncertainties and a real priority to have good laboratory surveillance and monitoring of the circumstances in the southern hemisphere and the ongoing occurrence here in the U.S.  Next question? 
Operator: The next is from Allen Miranda.  Your line is open. 

Alan Miranda: Hi.  Well, I would like to follow up on what you just said.  You said also at the beginning that there are also other kinds of viruses circulating.  And I was about to ask you, if this virus could reassort with any other kind, any other strain, Avian flu, for instance. 

Anne Schuchat: Unfortunately, reassortment happens. And this means that the viruses that we're seeing can exchange genetic material with other viruses that are circulating.  This can happen in humans, in pigs, in birds.  And so, we do always have a risk that the viruses will exchange genetic material and get worse, or hopefully, get better, if they do that.  So, we do think that the simultaneous occurrence in the world right now of this novel H1N1 strain that appears to be very transmissible and very virulent H5N1 (Editor’s note – this is a correction) strains that are endemic in animals in certain countries of the world in the avian population and the seasonal H1N1 strain that is oseltamivir resistant is an unusual circumstance.  Certainly, our efforts to control seasonal influenza with our annual immunization campaign will be important, and of course, there are discussions going on about vaccine development and potentially manufacturing and even use, eventually, of an H1N1 virus vaccine.  Those are important discussions, as well as the ongoing efforts to try to control the Avian H5N1 problem in birds in some of the world.  Next question?

Operator: I'm showing no questions at this time. 

Tom Skinner: Okay.  Rose, thank you, and thank you all for joining us for this update.  Please stay tuned and continue to go to www.cdc.gov for updated information, and we'll keep you apprised as developments warrant.  Thank you. 

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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES