CDC Telebriefing Transcript

Flu Season Begins; West Nile Virus Investigation Update

October 3, 2002

CDC MODERATOR: Thank you, Andrea.

Welcome, everyone. Thank you for being online. Today, we are going to talk about flu season as well as giving a West Nile virus investigation update. We would start the call by talking about flu and then talk about West Nile virus after we do the flu presentation and take questions about flu. Then we will do West Nile questions afterwards. A presentation's made there too.

On the line with us talking about flu will be Dr. Scott Harper. His name is spelled is S-c-o-t-t H-a-r-p-e-r. He is a CDC influenza expert in CDC's National Center for Infectious Diseases.

Talking about West Nile virus later in this call will be Dr. Lyle Petersen. Lyle, L-y-l-e, Petersen, P-e-t-e-r-s-e-n. He is CDC's West Nile virus expert and he will be joined by Dr. Matthew Boulton. He's a state epidemiologist from Michigan's Department of Community Health. Matthew is spelled M-a-t-t-h-e-w. Boulton spelled B as in boy o-u-l-t-o-n.

Again, we will start by talking about flu. I'd like to introduce Dr. Scott Harper.

DR. HARPER: Thanks. Just a couple of words about influenza. I think that a lot of people consider it that influenza's an especially severe cold but in fact it's a potentially life-threatening infection which kills about 20,000 Americans every year, and it hospitalizes over 100,000 Americans every year.

So it takes a heavy toll from both a mortality and a morbidity perspective, and it consistently taxes our health care system, especially in more severe seasons.

Despite that, a vaccine, as everybody knows, is available for influenza and recommendations regarding who should get it and when are put out annually by the Advisory Committee on Immunization Practices in the CDC.

And a couple of important points about the vaccine. It protects only against those viruses which cause influenza, not against organisms that cause things like the common cold, and a vaccine can't actually give somebody influenza, since it's made from killed viruses, despite what a lot of people think.

The vaccine's in ample supply this year. They're going to have about 94 million doses produced, which is the most that has ever been produced for the United States, and about 80 percent of that should be out by the end of October, in a much more timely fashion than what we've seen in the last couple of seasons.

Regarding timing of vaccination, practitioners should be giving vaccine to four groups primarily in October, and then everybody else in November and later.

And those four groups are, number one, those at high risk for sustaining complications from influenza such as the elderly and those with chronic heart and lung conditions.

Number two, health care workers. Number three, household members, the persons who are at high risk from flu-related complications. And then finally, number four, children who are under the age of nine and are getting vaccine for the first time since those kids need to get two doses.

In addition, while it's not an official recommendation yet, it's now encouraged that healthy infants, age six to 23 months should be vaccinated when feasible, because this population's at increased risk for influenza-related hospitalizations.

And with that, let's see if there are questions.

CDC MODERATOR: Thank you, Dr. Harper.

If you could identify yourself as well as what medium you're from, we would appreciate it. We will now take questions for Dr. Harper on flu.

AT&T MODERATOR: If there are questions or comments, please press one on your phone at this time. Again, if there are questions or comments, please press one on your phone at this time.

Anita Manning from USA Today, your line is open.

QUESTION: Hi, Dr. Harper, thanks for taking the call. Have you seen flu yet this season?

DR. HARPER: There has been, not unexpectedly, influenza reported across the country. This happens year-around, in fact, with sporadic cases being reported, and even some small outbreaks, and between May and September there have been a number of cases that have been reported in the United States.

QUESTION: Okay. Anything about that means? Is it a large number? Does it suggest that we might be "in for it" this year?

DR. HARPER: No; it doesn't. Every year we see the same sort of activity in the United States. There's been slightly increased reporting this year but that's probably due to the fact that people have been looking for it more this year.

CDC MODERATOR: Thank you, Dr. Harper. Next question, please.

AT&T MODERATOR: The next question comes from John Larman [ph] from Bloomberg News. Your line is open.

QUESTION: Thanks for taking my question. Do you expect to be able to use all that vaccine this year? Do you think that we'll use all--you said 90 million doses; right?

DR. HARPER: 94 million doses.

QUESTION: 94 million doses. Do you think that--in the past, has all the vaccine been used up every year it's been offered, and do you expect all that to be used?

DR. HARPER: That's a good question. In fact all the vaccine is not used every year and some is returned, and so I think the key take-home point from that is that education of practitioners and education of patients needs to continue to take place early in the season, so that folks get vaccine, because it is available in a very timely fashion this year.

CDC MODERATOR: Thank you, Dr. Harper. Can we have our next question, please.

AT&T MODERATOR: Helen Chickering from NBC News. Your line is open.

QUESTION: Thank you. A couple of questions. One, what strain will the flu vaccine cover? What strains? And any concerns about still what worries over West Nile virus as we enter flu season?

DR. HARPER: Addressing your first question, every year the influenza vaccine carries three strains of influenza against which it protects. This year those strains are an A Panama-like virus, an A New Caledonia-like virus, and B, Hong Kong-like virus, and we'll--I guess maybe you could elaborate a little bit more on your second question.

Are you asking about West Nile as related to influenza?

QUESTION: Because the symptoms are similar are you worried about people, you know, flooding their doctors' offices? I know that the mosquito season will die off as flu season kicks off, but there may be some overlap in warmer areas and are you still concerned about people worried they have West Nile and they may have the flu or just what the impact may be on emergency rooms and physician offices?

DR. HARPER: I think that's a really good point, and more so from sort of a generic or global point of view. Influenza seasons in this country, when they are more severe, have a tendency to really impact our health care infrastructure and emergency rooms, whether West Nile or any other things are circulating, these emergency rooms can really get overloaded and primary health care folks can really stay busy with cases of influenza, especially again in more severe seasons.

So I think the real question is one of influenza you know, as it relates to our ability to handle what could potentially be an increasing burden due to influenza, especially as the population is aging in this country.

QUESTION: I don't want to hog the time, but do you think the slight increase in people being diagnosed from May to September was due to people thinking maybe they had West Nile virus and getting diagnosed with the flu?

DR. HARPER: I think that that's less likely. For one thing, West Nile does not cause respiratory symptoms. Influenza, especially in younger people, can present with only a sort of a febrile illness, although much, much, much more commonly seen to have respiratory symptoms with it. So I really think that that's--the increase that was seen may be more of a reporting bias. In other words, the surveillance for influenza year round has more recently been ramped up, and you know, people are looking for it more now, and so this was not something that was alarming to anybody by any means.

In fact, this confirmed what we already suspected, and that's influenza viruses circulate year round. It's just that their impact is greater in the winter months.

CDC MODERATOR: Thank you. Our next question, please.

AT&T MODERATOR: Next question comes from Bill Scanlon from Rocky Mountain News. Your line is open.

QUESTION: Yes. Is there any mercury in the vaccine, and if it is, does that pose an increased risk to the infants that are going to be vaccinated for the first time?

DR. HARPER: Well, that's a two-part question. Number one, is there a thimerosal. I assume you're referring to thimerosal preservative in influenza vaccine. Yes, there is. This year one of the vaccine companies has made thimerosal-free influenza vaccine, and that will be available a bit later in the season for practitioners who choose to use it.

Your second question is one which I really can't address because the data on that are still, I think being collected and are out there. And that's a whole huge topic in itself, not just related to thimerosal in influenza vaccines, but thimerosal in any vaccines and whether or not it causes problems in childhood. And so that's something that I don't think I can comment on right now.

CDC MODERATOR: Thank you, Dr. Harper.

Next question, please.

AT&T MODERATOR: Next question comes from Jill Birken from the Minneapolis Star Tribune.

QUESTION: Can you tell me why there is so much vaccine available this year? Have you worked with manufacturers to ensure that this happened or are there other factors as well?

DR. HARPER: I think for one thing, that, you know, people over the last couple of years realized that the whole vaccine manufacturing and distribution system really was rather fragile, and that if problems occurred anywhere along the path from recommendation to getting vaccine into arm, it was a very vulnerable system.

And so I think that over the least year to two years there have been many discussions with vaccine manufacturers in multiple formats to try to correct those problems which occurred a couple of years ago especially. So it wasn't just CDC which was working with manufacturers, but FDA as well.

And I think that also production of vaccine, influenza vaccine at least, is not always based necessarily just on public health concerns, but it's also industry driven, and so there are supply and demand issues at work as well.

QUESTION: How many manufacturers do we have this year?

DR. HARPER: Sorry?

QUESTION: How many manufacturers are making the vaccine this year?

DR. HARPER: There are 3 manufacturers making vaccine for the United States.

CDC MODERATOR: Thank you, Dr. Harper.

Next question, please.

AT&T MODERATOR: Next question comes from the line of Maryn McKenna from the Atlanta Journal.

QUESTION: Thanks for doing this briefing. Actually, the Minneapolis reporter just asked my question.

CDC MODERATOR: Thank you. Next question, please.

AT&T MODERATOR: Next question comes from the line of John Pope from the Times Picayune. Please go ahead, sir.

QUESTION: Hi. I have two small questions. First of all, would you please go over the strains again that are in the vaccine. I didn't hear a B type.

DR. HARPER: Yes. The B type is a B Hong Kong--

QUESTION: Oh, it's B Hong Kong.

DR. HARPER: Yes.

QUESTION: And it's A Panama and A?

DR. HARPER: New Caledonia.

QUESTION: New Caledonia. Okay.

Second question. Is there going to be some kind of education program accompanying this to get more people out to get the vaccine? I'm asking because I was working in DeKalb County last year, and we tried to increase vaccine participation among older African-Americans in the county because there had been a significant disparity. And I was wondering if CDC was going to try to address that in getting--in persuading more people to get vaccinated?

DR. HARPER: Yes. CDC's National Immunization Program is hard at work, and has been in the past, and they continue to do so, not just for those sorts of disparities that you mentioned, but also in regard to the new encouragement that 6 to 23-month-old children get vaccinated. There's also educational pushes to have high risk people under the age of 65 vaccinated. That's been an area which has needed some work for the last few years.

So the answer to your question, to that question is yes, there are educational campaigns in process.

QUESTION: One follow up. Because there seems to be an ample supply of vaccine this year, there will not be the triaging that went on in previous years, where people were sort of being urged to go out in waves to get vaccinated?

DR. HARPER: It depends on what you mean by triaging. There is still a recommendation timeline that was put out by the ACIP and CDC back in April, and that would mainly focus on those 4 groups that I mentioned that should be vaccinated in October, and then everybody else vaccinated in November. So in fact, there is still a recommendation that higher risk groups get vaccine earlier than everyone else.

QUESTION: Thank you.

CDC MODERATOR: Thank you, Dr. Harper. We'll take 2 more questions for Dr. Harper. Then we're going to move to the second part of our program. So next question, please.

AT&T MODERATOR: Thank you. Jill Birken from the Minneapolis Star Tribune does have a follow up.

QUESTION: Thanks for taking another question from me. What was your rationale for deciding to recommend the vaccine or encourage the vaccine for children under 2 this year as opposed to previous years? Was there some new data that came to light that suggested these children are at high risk? Could you elaborate on your reasons?

DR. HARPER: Sure. There are some data which have emerged in the recent past, looking at rates of hospitalization specifically in that age group, and it looks like those kids, 6 to 23 months of age, are as at high a risk for being hospitalized secondary to influenza as people in high risk groups both under and over the age of 65. So that's the primary reason that that encouragement--again, not a recommendation, but encouragement, is in place.

CDC MODERATOR: Thank you. Please, final question for Dr. Harper.

AT&T MODERATOR: There are no more questions at this time, Mr. Robuck.

CDC MODERATOR: Okay. Dr. Harper is going to remain on this briefing. He also will be available to answer questions. Just call the CDC Press Office.

So, thank you, Dr. Harper.

I'd now like to talk--let Dr. Lyle Petersen make a short presentation. And again I remind you that Dr. Matthew Boulton from Michigan is also on this call.

And, Dr. Petersen?

DR. PETERSEN: Thank you, Von.

As of the 2nd of October the total number of West Nile virus cases reported to CDC reached 2,530 with 125 deaths. 32 states and Washington, D.C. have reported human cases of West Nile virus in 2002. The CDC, the Food and Drug Administration, the Health Resources and Services Administration, in collaboration with blood collection agencies in state and local health departments, continue to investigate West Nile virus infections in recipients of blood products and organ transplantation.

CDC has received reports from 10 states of 15 patients with confirmed West Nile virus infection, diagnosed after receiving blood products, within one month of illness onset. These 15 patients received blood products from 2 to 185 individual donors. It is likely that not all of the 15 patients were infected via blood products. All lived in the areas with active West Nile virus activity and thus may have been infected via mosquito bites.

To recap the investigation so far, West Nile virus transmission from blood products has been confirmed in 3 patients. In a Mississippi investigation West Nile virus was cultured from a blood product associated with a blood donor of one of these cases. In a Michigan investigation 2 patients tested positive for West Nile virus infection after receiving different blood products derived from a single blood donation, subsequently found to have evidence of West Nile virus.

I will now describe the investigation of one of these two Michigan blood recipients. The CDC and the Michigan Department of Community Health are continuing to investigate the West Nile virus infection in a woman who received a blood transfusion who later became ill from West Nile virus. She had been breast feeding, and her breast milk was shown to have evidence of West Nile virus genetic material. Attempts to culture West Nile virus from the breast milk are still underway. Her infant has remained healthy; however, a blood sample from the infant demonstrated IGM antibodies to the West Nile virus, indicating that the infant had been infected with the West Nile virus.

The infant is now the youngest person recorded with West Nile virus-specific IGM antibody since West Nile virus was first recognized in the United States in 1999.

During 1999 to 2001, no cases of West Nile virus illness in children under one year of age were reported to the CDC. In 2002, four children under the age of one year have been reported to CDC.

Because the health benefits of breast feeding are well-established and the risk for West Nile transmission through breast feeding is unknown, we do not suggest a change in breast feeding recommendations.

Women who are ill or experience difficulties, as always, may want to consult with their physician about breast feeding.

For more information on West Nile virus, the public may call the CDC hotline at 1-888-246-2675. I'll repeat that number. It's 1-888-246-2675. Thank you.

CDC MODERATOR: Thank you, Dr. Petersen. I remind listeners that, again, Dr. Boulton from Michigan is also on.

We will start with questions and answers at this point. The first question, please.

AT&T MODERATOR: Thank you. The first question comes from Miriam Falco from CNN.

QUESTION: Hi, Dr. Petersen. Regarding the transmission in this Michigan woman and her child, from the MMWR it didn't sound like you're saying a 100 sure that it was transmitted through the blood, milk, or are you? And do you have any idea why the child didn't get sick? Just cause he happened to be one of the 80 percent that don't? Or could it be that the infant was so young and the immune system, or the breast milk, or why do you think the child didn't get sick?

DR. PETERSEN: Okay. To answer your first question, as we've talked about in previous conversations or press telebriefings, one of the problems with all of these cases is that they're occurring in areas where West Nile virus transmission is ongoing due to mosquito bites.

So you cannot ascertain with a 100 percent certainty how a person became infected. In this case the infant had minimal exposure, outdoor exposure, and exposure to mosquitoes, so we think it is very likely that the child became infected via the breast milk, but we can't determine this with a 100 percent certainty.

As to your question of why the infant was not sick, one of the things that we know, as I said, West Nile virus is--or illness due to West Nile virus is highly related to age, with older age being a significant risk factor for developing severe complications of West Nile virus.

The fact that this child was very young suggests that the child may have been at less risk for developing severe complications.

QUESTION: Now if I may follow up. Last week, you knew, or I think you knew that there were antibodies, and then you were in a culture test. Have blood tests from the child led you to believe that the child [inaudible] was the antibodies from the mother that may have been passed through the breast milk?

DR. PETERSEN: IGM antibody is poorly absorbed through breast milk to the infant, and that's--if there was any IGM antibody that was passed from mother to infant, it would have been an extremely small amount. So the fact that child has demonstrable IGM antibody on a blood test indicates that the child was actually infected with West Nile virus.

CDC MODERATOR: Next question, please.

AT&T MODERATOR: The next question comes from Mark Kaufman from the Washington Post. Please go ahead.

QUESTION: Yes. I was interested in the four additional cases that you folks are looking at. Can you tell us anything more about them in terms of where the children are and what the status is of the testing?

DR. PETERSEN: We have had four infants under the age of one year who have been documented to have West Nile virus-related disease. Three of these persons have West Nile virus. Excuse me. All four of these people have West Nile virus, meningoencephalitis. [inaudible]. Excuse me.

In addition to our child here, there have been three others that have been reported. All of these have West Nile virus, meningoencephalitis. At least one of these children was not breast feeding. The others ones are under investigation.

DR. BOULTON: This is Dr. Boulton. I might mention that one of those additional children was in the State of Michigan, was a 9-month-old who did have meningoencephalitis but has completely recovered now.

DR. PETERSEN: Yeah. This is Lyle Petersen again. I did make a mistake. We have, in addition to this child who is asymptomatic, there are four infants with West Nile virus illness under the age of one. They're age two, three, nine and eleven months, and three of the infants we do not have information about their breast feeding status.

One of those we do have information about the breast feeding status and that child was not breast feeding.

QUESTION: And is there any way, if any of these children it turns out were breast fed--is there any way to determine whether or not they have gotten the virus through the breast milk at this stage?

DR. PETERSEN: There's no way to determine this with absolutely frequency--I mean with absolutely certainty. The one thing that we would do, if possible, is test the mother for IGM antibody. If the mother is IGM antibody negative, it indicates that the mother was never infected with the West Nile virus, and that would provide some data about potential transmission.

DR. BOULTON: This is Dr. Boulton. Just to enlarge on what Dr. Petersen was saying about West Nile virus activity, you may have noticed that Michigan has, as of yesterday, 370 human cases of West Nile virus and 24 deaths, so that places at the very high end of the spectrum for states with West Nile virus human cases.

CDC MODERATOR: Thank you, Dr. Boulton. Next question, please.

AT&T MODERATOR: The next question comes from Meagan Brooks from Reuters Health. Please go ahead.

QUESTION: Yeah; hi. The AP is reporting this morning about the woman who received a kidney transplant last month and died after testing positive for West Nile. Can you all comment on that at all?

DR. PETERSEN: This was the patient in Maryland? I've not seen the AP report, but I believe this was a report of a kidney recipient from Maryland. We do not have--the current status of that investigation, as I've said, we do not believe the infection was acquired through the kidney transplant itself but may have been acquired through the blood products given to that patient after the transplant.

We are working currently with the Maryland State Department of Health in investigating that case.

CDC MODERATOR: Thank you, Dr. Petersen. Next question, please.

AT&T MODERATOR: Anita Manning from USA Today, your line is open.

QUESTION: Hi. Dr. Petersen, I got lost there with the four or five children, and who was breast feeding and who wasn't.

DR. PETERSEN: Yeah. Excuse me. I think I confused you here. I was working late last night on this MMWR, so please excuse me. Right now, in 2002, there were four infants with West Nile virus illness that have been reported to CDC.

These are aged two, three, nine and eleven months. One of these infants we know for sure was no breast feeding. The status of the other three infants is being investigated.

During 1999 through 2001, there were no cases of infants under the age of one year reported to CDC. Is that clear?

QUESTION: Well, except that now we have a fifth child who we know was breast feeding and has West Nile--

DR. PETERSEN: Right but this child did not have West Nile virus illness.

QUESTION: Okay; didn't get ill. Gotcha. And other thing is, this is a small thing but--so that when we're reporting, we don't have to keep saying this infant, this baby, this infant. Can you just say if it's a male or female child?

DR. PETERSEN: This is a question for Dr. Boulton.

DR. BOULTON: Per the parents' request, we're not revealing the gender of the child.

QUESTION: Oh, okay; thank you.

CDC MODERATOR: Thank you, Dr. Boulton. Next question, please.

AT&T MODERATOR: The next question comes from Erica Newdalski [ph] from Baltimore Sun.

QUESTION: I'm also following up on the Maryland case.

CDC MODERATOR: Excuse me, Erica, we could barely hear you. Could you speak up, please.

QUESTION: I'm also following up on the Maryland case of the kidney recipient and that blood, the blood products I guess are now being traced.

Can you explain to me, if there's no screening test for donated blood, the way there is for HIV or hepatitis, what is the test that you go back and do if you suspect that blood products or donated blood may be carrying the virus?

DR. PETERSEN: Yeah, that's an excellent question. There's a couple of things we do. What happens when people donate blood is commonly there's a small amount of blood that is retained in case there's some need to test it in the future.

For example, if the person has a blood transfusion reaction, they can use that blood to help determine what's going on.

And so in many of these cases that we identify, some of the this retained blood is actually available to test retrospectively. And we test that blood using a polymerase chain reaction or PCR test to look for virus genetic material. So that's what we're doing in these cases.

Now, we also, in samples where we find that there is West Nile virus genetic material by PCR, we also try and find the donor again and test them for West Nile virus antibodies, and this helps confirm that in fact, as the PCR test indicates, that the donor was viremic at the time of donation.

QUESTION: Why can't you use a test like that to screen blood beforehand?

DR. PETERSEN: Well, this is what the Food and Drug Administration is currently dealing with, the manufacturers of--yeah, the manufacturers of test kits to develop. One of the problems right now is, is that the PCR testing is a laboratory test basically now. It's designed for research laboratories. And it's not applicable to mass screening situations right now.

But the FDA is actively working with the manufacturers to try and develop a test that could be used for mass blood donor screening.

QUESTION: Thank you.

CDC MODERATOR: Thank you, Dr. Petersen.

Next question, please.

AT&T MODERATOR: The next question comes from Bill Scanlon from the Rocky Mountain News.

QUESTION: Yes. What is the current recommendation for people who consider elective surgery, necessary surgery, et cetera, regarding the blood supply and West Nile?

DR. PETERSEN: Well, the current recommendation is, is that West Nile virus should be a consideration for elective surgery, and it may--a patient may want to consider delaying elective surgery because of a potential risk of West Nile virus infection from the blood transfusion.

But I would like to emphasize two points right now. One point is, is that the West Nile virus season is waning, and thus, blood transfusions that are collected or blood that is collected is likely to be safer and safer as we get later on in the season. The second thing is, is although we've identified these cases which seem very probable to have West Nile virus transmission through a blood transfusion, the risk is probably still very small.

And my overall advice was that West Nile virus should be a consideration in delaying elective surgery, although it's not a major consideration.

CDC MODERATOR: Thank you, Dr. Petersen.

Next question, please.

AT&T MODERATOR: Next question comes from Detra Henderson from Denver Post.

QUESTION: Thank you very much for doing this again. Is there any indication that West Nile is transmitted to the child from the mother through the birth canal?

DR. PETERSEN: We have no evidence that that's the case. We have not seen these kinds of cases before.

CDC MODERATOR: Thank you, Dr. Petersen.

Next question, please.

AT&T MODERATOR: Next question comes from Mark Hoffman from the Washington Post.

QUESTION: In the mother that you were talking about in the Michigan case, how do you know that she had not been bitten by a mosquito prior to giving birth? And on the four other youngsters, what is their current condition?

DR. PETERSEN: Let me answer the second question. I do not know the current condition of the four infants right now.

To answer your first condition, how do we know--I mean your first question, how do we know that the mother did not get bitten by a mosquito? We don't know that. Though what we do know is, is that the mother received a blood transfusion where the donor was shown to have evidence, retrospectively, shown to have evidence of West Nile virus in the blood at the time of donation, and this same donor is associated with another recipient who has developed West Nile virus infection.

So the overwhelming evidence suggests that the mother did in fact get infected via the blood transfusion, but as I mentioned earlier, we cannot rule out with 100 percent certainty that the mother did not get infected via mosquito bite.

CDC MODERATOR: Thank you, Dr. Petersen.

Next question, please.

AT&T MODERATOR: Next question comes from Maryn McKenna from Atlanta Journal.

QUESTION: Hi. Thanks so much for doing these briefings. A couple of questions. First, Dr. Petersen, could you just explain how you have been able to rule out that given that the infant in this breast feeding case that you're discussing today had a positive antibody test, but did not develop West Nile illness, have you been able to rule out the antibodies being passed to the infant prenatally? And then I have a follow up question.

DR. PETERSEN: We cannot totally rule this out, but what we have done is we've discussed with national experts who are much more familiar with breast feeding issues than myself, and the consensus of all of the national experts that we've consulted with is, is the amount of IGM antibody that could potentially be transmitted to the infant via the breast milk is very low, and thus would not be picked up on a serum test for West Nile virus antibody in the infant. That's--the overwhelming evidence is, is that the child was actually infected with the West Nile virus.

QUESTION: Okay, thanks. My second question is, give that as you say today breast milk is being considered the most likely source of infection, are you, you collectively, turning to any consideration of whether West Nile can be present in or be transmitted by any other body fluids?

DR. PETERSEN: We--other than blood, which we're showing through the blood transfusion related cases, we do not have any evidence that West Nile virus is transmitted by any other body fluid.

QUESTION: Thank you.

CDC MODERATOR: Thank you, Dr. Petersen.

Next question, please.

AT&T MODERATOR: [Inaudible] from Bloomberg News. Your line is open.

QUESTION: My question's been answered. Thanks.

CDC MODERATOR: Okay. Thank you.

Next question, please.

AT&T MODERATOR: If there are additional questions or comments, please press 1 on your phone at this time.

Anita Manning from USA Today has a follow up question.

QUESTION: Yes. My follow up question is have you looked in any other body fluids?

DR. PETERSEN: We have not looked in other body fluids.

QUESTION: Thank you. Are you going to?

[Laughter.]

DR. PETERSEN: You're being tough on me today.

QUESTION: I'm sorry.

DR. PETERSEN: We currently have no plans to look in other body fluids. What we know from the epidemiology of this virus, including the epidemic this year, is that 99.99 percent of the infections are spread by mosquito bites. We have no epidemiological evidence that the infections are spread by anything other than mosquito bites or blood transfusions or receipt of organs, and in this case we report today, potentially through breast milk as well, although all of these latter forms of transmissions appear to be very rare.

We have no evidence epidemiologically of any other forms of transmission at this time.

CDC MODERATOR: Thank you, Dr. Petersen.

Any other questions?

AT&T MODERATOR: Yes. We have a follow up from Miriam Falco from CNN.

QUESTION: Hi. Regarding the total number of blood donors that have blood product with West Nile virus in it, you said 2 to 185; is that right?

DR. PETERSEN: Correct. No. What we said was is that these people under investigation had received anywhere from 2 to 185 blood products.

QUESTION: Okay.

DR. PETERSEN: Which I think points to why these investigations are so difficult to do, because there's a tremendous number of donors involved.

QUESTION: And how successful has the FDA been in tracking down these people for these follow up tests that you mentioned earlier? Do you have any idea?

DR. PETERSEN: Well, the FDA is actually not tracking down the people. The blood collection agencies are tracking down these people, and they're generally very successful in doing so. We've had very good collaboration with the blood collection agencies, and the blood collection agencies actually are used to tracking down people for potential blood related infectious disease transmissions. So this is not an unusual thing for them to be doing, and they're quite good at it. And in general the blood donors are extremely cooperative.

CDC MODERATOR: Thank you, Dr. Petersen.

Any other questions?

AT&T MODERATOR: Yes. We have a question from Erica Nadowsky from the Baltimore Sun.

QUESTION: Why wasn't the mass screening test--or why hasn't it been developed sooner? Was West Nile just not a big enough public health threat, and what is the cost of developing that kind of test?

DR. PETERSEN: That's an excellent question. The potential risk of West Nile virus transmission through blood transfusion had been something that we had considered in previous years, and in fact, we had done some modeling, mathematical modeling which showed that it was in fact probably a rare event. And so this was a consideration.

But up until this year, West Nile virus has never been shown to be transmitted via blood transfusion, so there was no need, demonstrable need to screen the blood supply. We've made very significant progress in the last few years of developing tests like the TACman test, that have been used to detect the genetic material of the West Nile virus, that can be adapted to a blood donor screening situation if need be, and that's what's being done right now.

So to answer your question is, is that before this year there was no evidence that such a test was actually needed. It was only a theoretical risk/

QUESTION: Do you have any idea what the cost of developing, you know, to the point where you can screen, what that would cost?

DR. PETERSEN: I do not know the answer to that question, and that question is probably most appropriately answered by the Food and Drug Administration, or manufacturers who may be interested in developing such a test.

QUESTION: Thank you.

CDC MODERATOR: Thank you, Dr. Petersen.

We'll take a final question. Any other questions, please?

AT&T MODERATOR: Yes. Final question come from David Polson from Booth Newspaper.

QUESTION: Yes. I just wanted to clarify. Did the Michigan woman who got the blood transfusion, did she receive it after giving birth?

DR. BOULTON: This is Dr. Boulton. Yes, she did. She received it approximately 6 hours after she gave birth, and then she received a second transfusion, which is the transfusion that's been linked with West Nile infection, the following day. So she received 2 units of packed red blood cells.

CDC MODERATOR: Thank you, Dr. Boulton.

I'll just leave it open for final comments. Dr. Boulton, any final comments from you of things that were covered today?

DR. BOULTON: I just might note that I think one of the real challenges in a situation like this is that we have a specific individual case that we're developing new information on, and to take information from that and develop population level recommendation is a very challenging thing to do, particularly when these findings are new. We have not seen them previously. And I think that really warrants caution, and I think that more than anything, that's why we would continue to recommend that women breast feed given the well documented benefits of doing so.

CDC MODERATOR: Thank you, Dr. Boulton.

Dr. Petersen, any final comments?

DR. PETERSEN: Yes. I would like to emphasize again what Dr. Boulton has just mentioned, and our opinion here is, is that the benefits of breast feeding by far outweigh any potential risks of breast feeding, including the risk of West Nile virus transmission.

CDC MODERATOR: Thank you, Dr. Petersen.

Thank you, everyone, for being on the call again. Just a reminder, there will be a transcript up on the website later this afternoon. There will also be some other information in the news.

So thank you for being on the call. Thank you, Dr. Boulton. Thank you, Dr. Petersen. And thank you, Dr. Harper. Have a good afternoon.
[End of teleconference.]

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