Transcript for CDC Telebriefing: Zika Virus Update – August 19

Press Briefing Transcript

Friday, August 19, 2016, at 2 P.M. EST

Please Note:This transcript is not edited and may contain errors.

OPERATOR:  Welcome and thank you for standing by.  All participants will be able to listen only until the question and answer portion of today’s conference.  To ask a question, please press star 1.  I would now like to turn your conference over to Michelle Bonds.  Miss, you may begin.

MICHELLE BONDS:  Thank you, Julie.  Thank you all for joining us today for the briefing on Zika in Florida.  Joining us today is Dr. Tom Frieden, director of the CDC.  I’ll now turn the call over to Dr. Frieden.

TOM FRIEDEN:  Thank you for joining us.  CDC is working with the state of Florida every day to monitor the spread of Zika in real time and give updated guidance to the public as we learn more.  On July 29th, we first reported local transmission of Zika in the United States.  Soon after, the Florida health department identified an area in the Wynwood neighborhood of Miami where Zika was being spread by mosquitos.

CDC has been working closely with Florida public health officials to investigate these cases, monitor for new cases, and control mosquitos there as completely as possible.  CDC and Florida have issued travel, testing, and other recommendations for people who traveled to or lived in the Wynwood area on or after June 15th, 2016.  That’s the earliest known date that one of the people there could have been infected with the Zika virus from local mosquitos.
Although the state of Florida with CDC’s assistance has mounted and continues to mount an aggressive response, the mosquitos are persistent and we won’t know for at least another couple of weeks if these aggressive control measures have worked.  In recent weeks the Florida health department has also identified and investigated at least four other independent instances of mosquito-borne Zika transmission in Miami-Dade County.  These are individual instances and do not represent spread throughout the area, but rather, are single cases.

Over the past 24 hours, however, a new area of active Zika transmission has been identified in a section of Miami Beach.  As a result, we now recommend the following.  Pregnant women should avoid travel to the designated area of Miami Beach, in addition to the designated area of Wynwood, because active local transmission of Zika has been confirmed.  Pregnant women and their partners living in or traveling to the designated areas should be aware of active Zika virus transmission and do everything they can to prevent mosquito bites.  Those who live in or have traveled to the designated area of Miami Beach since July 14th, 2016, should be aware of active Zika virus transmission and people who have a pregnant sex partner should consistently and correctly use condoms to prevent infection when they have sex.  Pregnant women and their sexual partners who are concerned about potential Zika virus exposure may also consider postponing nonessential travel to all parts of Miami-Dade County.

More broadly and not just with respect to Florida, all pregnant women anywhere in the US should be evaluated for possible Zika virus exposure during each prenatal care visit.  These evaluations should include an assessment of the symptoms of Zika virus disease such as fever, rash, arthralgia, and conjunctivitis, their travel history, and their potential partners’ exposure to Zika virus.  Women with Zika should wait at least 8 weeks after symptoms start before trying to get pregnant.  Men with Zika should wait at least 6 months after symptoms start before couples try to get pregnant.  And women and men without confirmed Zika who traveled to areas where Zika may be spreading should wait at least 8 weeks before trying to get pregnant.  Women and men who live in or frequently travel to areas where Zika is spreading, and this includes now the two confirmed zones in Miami-Dade County, and who don’t have signs and symptoms of Zika, should talk to their health care provider to inform their decisions about the timing of pregnancy.

There are undoubtedly more infections that we’re not aware of right now.  Most people, perhaps four out of five with Zika infection, don’t have any symptoms.  It can take up to 2 weeks for those who do have symptoms for those symptoms to appear after infection.  And investigations into local cases can take days to weeks.  It is not quick or easy to determine if cases are locally acquired and if they’re related.  Because of this, there may be a time lag between the spread of disease locally and the recognition of that spread.  That is one reason we would advise everyone living in or traveling to Miami-Dade County to be aware that Zika could be spreading there and to enhance their efforts to avoid mosquito bites.  And as indicated previously, pregnant women and their sexual partners who are concerned about Zika infection might consider postponing nonessential travel to Miami-Dade County.

We can’t predict how long this will continue, but we do know that it will be difficult to control.  Even for the small six-block area in the Wynwood neighborhood, it has been difficult to control the mosquitos that spread this disease.  State officials continue to quickly implement effective mosquito control programs and conduct enhanced case monitoring in these areas.

Zika spreads by the movement of people.  For example, by someone who goes to one area anywhere in the world where Zika is spreading and then travels to another and may be bitten by an Aedes Aegypti mosquito.  That infected mosquito after about a week can bite people within about 500 feet and potentially start a new cluster.

While clusters like this are anticipated, it’s not an indicator that Zika is spreading throughout an area such as the county of Miami-Dade.  We do understand that this is concerning, especially for pregnant women.  Decisions to update our recommendations and our guidance are made on a real time basis. Based on the information that we have we’ll continue to update the public with what we know when we know it so people can make the decisions they need to to protect their health.  We also remind pregnant women that Zika continues to spread in countries around Latin America and the Caribbean and that map is updated continuously on our website.

Avoiding mosquito bites is hard.  But we’re encouraged by the poll released today that found that many Floridians are taking steps to protect themselves.  This is particularly important for pregnant women.

The bottom line here is that there’s a new area of active transmission of Zika in Miami-Dade, in Miami Beach in Florida, and there have also been several other instances of Zika being spread by mosquitos which have been isolated and don’t appear to have continued.  It’s important that pregnant women in areas that do have Aedes Aegypti mosquito presence take steps to protect themselves against mosquito bites as well as the sexual transmission of Zika.  CDC continues to have an emergency response team working hand in hand with the excellent public health staff in Florida and continues to do what we can to support the staff and the state and the communities that are affected.

MICHELLE BONDS:  Thank you, Dr. Frieden.  Julie, we are ready for questions.  Also joining Dr. Frieden in answering the questions is Dr. John Jernigan.

OPERATOR:  Thank you.  If you would like to ask a question please press star 1 and you will be prompted to record your first and last name.  Please unmute your phone when recording your name and to withdraw your question press star 2.  Our first question comes from Betsy McKay, Wall Street Journal. Your line is now open.

BETSY MCKAY: Hi, thanks very much. Dr. Frieden, I wanted to ask, you said there have been other instances. How many other possible clusters are there or have there been at this point? And then secondly, have mosquitoes tested positive in Miami-Dade or any neighboring counties, positive for Zika?

TOM FRIEDEN:  So in response to your first question, there were initially two different investigations of individual cases. Both of those investigations included by the Florida health department included community surveys and did not identify any additional cases. There are two additional cases that appear to be isolated, where there does not appear to be ongoing or persistent transmission.

So we do expect that we will see occasional cases of local transmission. The way this worked in chikungunya and in dengue in Florida, were that for every nine or so one-off cases, where there was a single case of transmission that was locally mosquito borne, there was one cluster.  But the vast majority of the local transmissions hit a dead end after one or two people in one household.  And that’s what we would anticipate seeing here.  We’ve now seen two instances where there is documented spread, and those are the two areas where we are urging pregnant women not to travel to and where if there are pregnant women in that area, we’re asking them to do everything possible to prevent mosquito bites.  We are not aware of any mosquito pools that have tested positive in Miami-Dade or elsewhere for the Zika virus.  It’s quite difficult to find the mosquitos that specifically spread Zika, because the rate of infection seems to be fairly low, given the mosquito population size.

BETSY MCKAY: Okay.  Thank you.

TOM FRIEDEN:  Next question.

MICHELLE BONDS: Next question?

OPERATOR: Our next question comes from Maggie Fox with NBC News.  Your line is open.

MAGGIE FOX: Thanks.  I just wanted to clarify the dates.  I think in the written release CDC said anyone who’d been in this particular area of Miami Beach since July 14th should consider Zika.  I think Dr. Frieden, I heard you say June 15th. Can you just update what that date is and can you tell us was it one person who tested positive and was there at that date or how did you come up with it, please?  Thanks.

TOM FRIEDEN: So the way we do this, is we basically count back 2 weeks from the first patient for Wynwood, that’s June 15th.  For Miami Beach, that’s July 14th.  Okay?

MICHELLE BONDS: Next question, please?

TOM FRIEDEN: Next question, please.

OPERATOR: Yes.  Our next question from Julie Steenhuysen with Reuters.  Your line is open.

JULIE STEENHUYSEN: Yeah, hi.  Thanks for taking my call.  So, Dr. Frieden, in his announcements today Governor Scott was saying he requested an additional 1,000 Zika prevention kits, and he said he’s repeatedly called on the federal government for additional kits and has not received them.  What’s the delay on that, and also, he mentioned that he has asked for a detailed plan on how to work with FEMA.  Does there need to be a declaration of a state of emergency before, what is the trigger for working with FEMA?  Thanks.

TOM FRIEDEN: Thank you.  First off, when I was in Florida with Governor Scott on August 4th he asked us for 10,000 Zika prevention kits.  What we did was rapidly provide 10,000 products of DEET for use there.  The Zika prevention kits contain many products, not all of which are necessarily useful in that context. We also advised the state that we had sent them funds, and we’ve sent the state of Florida more than $35 million for Zika and other emergencies to respond and that includes to purchase the other the products they might want in a Zika prevention kitovernor Scott, today, asked us for 5,000 Zika antibody test kits.  We heard that response, that request in his press conference today, we’ve already arranged for them to begin shipping and they will arrive Tuesday so we’re able to meet their response for that. We’re also able to provide the kind of laboratory support that is needed.  We’ve provided expert advice.  The Florida public health labs are doing an excellent job of testing for Zika virus.  They’ve actually been at the forefront of some of the innovations in Zika virus testing, and we’ve been able to provide them with some technical input on that.  In terms of FEMA, I think that is something that would have to be addressed to the broader U.S. government for response.

MICHELLE BONDS: Next question, please.

OPERATOR:  Out next question comes from Pam Belluck with the New York Times.  Your line is open.

PAM BELLUCK: Hi, Dr. Frieden.  The way that you issued this advisory includes an advisory for pregnant women not to travel to the designated area but a sort of strong suggestion which you repeated a couple times that if anybody who’s pregnant or their partners are concerned, they might consider not going to Miami-Dade at all.  And that was done, if I’m correct, because Florida has to request the area that CDC is able to warn people to travel, not to travel to.  Right?  So Florida designated that area as the only area to be included in the travel advisory and then did CDC then say, well, we need to do more here so we’re going to include this language that says consider postponing non-essential travel?  To the whole Miami-Dade County?

TOM FRIEDEN: Florida is following the CDC recommendations for defining a risk area.  The area that includes a buffer zone of at least a mile around an area where there’s confirmed Zika transmission.  What we’re doing is stepping back and saying there have been now multiple instances of individual transmission.  It’s a large county.  More than 2 million people live there.  More than 20,000 pregnant women.  So there are obviously many different parts of it with different ecological components, but we will always err on the side of providing more information to the public so that people can make more informed decisions about what they want to do to protect themselves.  And that’s why we’ve highlighted that while we’re quite concerned about these two areas, where we know there has been spread of Zika through local mosquitoes, we’re mentioning the fact that throughout Miami-Dade County there is the possibility that there could be transmission that hasn’t yet been identified so that people are aware of that, and then women living there can take steps to protect themselves, as the state of Florida has encouraged them to do as well, and people who are considering traveling there can factor that into their decisions.

MICHELLE BONDS: Next question, please.

OPERATOR: Our next question comes from Daniel Chang with the Miami Herald.  Your line is open.

DANIEL CHANG: Hi.  Thank you for taking my call.  Dr. Frieden, I wanted to ask if there was a possibility that today’s zone in Miami Beach could have been announced sooner?  Perhaps even yesterday.  The governor announced that there were two new local cases that were mosquito borne, the health department announced that both of those cases were outside of the Wynwood area that had previously been identified and today we learned there are five people at least who have contracted the virus including three tourists, one from Texas, and one from Taiwan, who were both in the area in late July, early August.  I heard what you said earlier about how it’s complicated and it takes a long time to go from confirmed case to announcement, but it seems like they had at least two cases within that square-mile diameter that had been confirmed, and I’m just wondering could this have been announced sooner?

TOM FREIEDEN: These are very complex investigations.  They involve identifying individuals, confirming their diagnosis, interviewing them.  Seeing if they went to other places where there might have been spread of the virus.  Seeing if they may have had sexual exposure to Zika, and then when transmission is confirmed, figuring out what makes sense in terms of the exact boundaries to be drawn.  So I’m appreciative that the state has drawn those boundaries, and we reiterate them as these being the two areas with confirmed transmission in Miami-Dade where we really need to focus on both the mosquito control and the information and support to people living there to reduce their risk of mosquito bites.

MICHELLE BONDS:  Next question, please.

OPERATOR: Our next question comes from Eben Brown with Fox News.  Your line is open.

EBEN BROWN: Thank you very much.  Thanks, doc, for taking the call.  You know, when we’re talking about Miami Beach and we look at the map that the Florida Department of Health put out with the outline we’re talking specifically about South Beach.  It’s a lot higher of a population density, and a lot more transient population, due to the high amounts of tourism or people who either live in the South Beach area for a part of the year and then live outside this nation for the other part of the year.  How does this add to the public health challenge in terms of tracking and controlling and, you know, one of the warnings people were given about the Wynwood situation was, well, if you use bug repellent and cover up, you’ll be safer.  Asking people to cover up in South Beach seems like it’s a bit difficult.  I don’t mean to be funny about that, but it’s known for a lot of skin and skimpy bathing suits for both men and women.

TOM FRIEDEN: Yes, we don’t think our advice to wear a long-sleeved shirt and long pants is likely to be widely followed in some of these areas, and this is one of the things that makes control more complicated.  In addition, because of the high-rise buildings it’s not an area where aerial spraying can be applied.  So each of the areas where disease is spreading needs to be handled individually and differently, but intensively, to try to knock down the mosquito populations, and to control, and to protect the individuals who are there.  Covered skin is safer than uncovered, but uncovered skin with DEET on it is also safe.  So getting mosquito repellent widely used is important, but because of the large numbers of people there, we do anticipate that there may well be other travel-associated or locally-identified cases that we determine are present. As we look for individuals, we will undoubtedly find individuals who had infections without symptoms.  We generally find about four people without symptoms for every one with symptoms.  So we do anticipate that additional infections will be documented.  The question is going to be for the Wynwood area, do those infections continue after controlled measures were put into place?  And that’s what we’re looking at, at this point, monitoring for very intensively.  For the Miami Beach area, Florida state, the county, ourselves, are looking very carefully with the hotels and the community there with what can be done to maximally reduce the risk of Zika by controlling the mosquito population and protecting people through things like the use of mosquito repellent such as those containing DEET.

MICHELLE BONDS: Next question, please.

OPERATOR: Our next question comes from Brady Dennis with Washington Post.  Your line is open.

BRADY DENNIS: Hi, Dr. Frieden.  Thanks for the call.  I just wanted to try to confirm something about the transmissions in both of these areas.  It sounded as if, you know, given the information that we have of where people who are infected live, that most if not all of the people who have picked up Zika in the Wynwood area were Florida residents, even though they lived in nearby counties, some of them.  This one in Miami Beach certainly seems to involve some tourists.  Are you able to shed light on that, that whether there were tourists in any of the Wynwood cases?  And certainly sounds like there are this time in Miami Beach.

TOM FRIEDEN: Yes.  You know, Miami Beach obviously attracts many more international tourists, and tourists from around the U.S. and because it’s a very specific area where people go and stay and are only there, it’s fairly easy to pinpoint when somebody, a traveler, comes back and said, “I was only here and I have Zika.”  So the existence of Zika in travelers to that area and the recognition of the cluster through the diagnosis of travelers is the kind of thing that we do see, and anticipate with many different infectious disease processes, where when you see something unusual in a traveler, you can basically deduce where it came from.  So often it’s somewhat easier to rapidly come to determination of what’s happening through people who have left an area and are in areas that are not at risk for that disease from any other means, especially if they’ve had limited travel while they were there.

MICHELLE BONDS: Next question, please.

OPERATOR: Our next question comes from Rob Stein with National Public Radio. Your line is open.

ROB STEIN: Thanks for taking my question.  I’m curious what your thoughts are on whether it will be harder, easier, about the same to control this outbreak in this part of Miami as it was in Wynwood?  How this part of the city compares with Wynwood.  And, also, curious what, how would you compare this outbreak so far with what you’ve seen in the past with dengue and chikungunya.

TOM FRIEDEN: Well, first off, comparing the two areas, Miami Beach does have a series of characteristics that make it particularly challenging.  The inability to use aerial spraying there means that we’ll be restricted to ground-based technologies like backpack spraying.  The large number of people, and the high turnover of people means that there could be ongoing people who are exposed, and the amount of exposed skin also makes it harder to reduce the risk of infections there.  So we think this will be a challenging area, and this is one reason why we’re monitoring very intensively.  In the Wynwood area we have seen substantial but not complete knock downs in the mosquito populations, and we continue to monitor rigorously every day to see whether additional cases arise after intensive mosquito control was started.  In terms of comparing this with other diseases such as dengue and chikungunya one of the things that is constant now and before is that these are localized incidents.  They are not incidences where the disease spreads throughout an entire area.  They’re diseases that spread through mosquitoes that don’t fly more than 150 meters and they’re spread by people moving from place to place and then getting bitten by new mosquitos that then start another localized instance of this.  However, we did not have, that we know of, outbreaks of chikungunya or dengue in highly populated cities such as Miami-Dade County.  So that is a different characteristic and something that we’re working very closely with the state and county on now.

MICHELLE BONDS: Next question.

OPERATOR: Yes, the next question comes from Jennifer Kay, the Associated Press. Your line is open.

JENNIFER KAY Hi, Dr. Frieden.  Can you explain why you can’t use aerial spraying over Miami Beach?  And are you, do you now believe that the aerial spraying is less effective than you might have thought it was when you were visiting here in Miami a couple weeks ago?

TOM FRIEDEN: So we continue to be quite impressed by the effectiveness of the aerial spraying in Wynwood.  We’re seeing consistently more than 90 percent of mosquitoes in traps killed during each spray event, we’re seeing very substantial reductions in the number of mosquitoes there.  We’re just impressed by the resilience of this mosquito.  It’s a tough mosquito to kill.  In terms of why it can’t be used in Miami Beach, the aircraft that spray ultra-low volumes of the products fly very low on the order of 100 feet above the ground.  So they can’t really do that around high-rises.  In addition, aerial spraying with ultra-low volume can only be done when there’s not much wind so that it can be very directly targeted to where it’s needed.  And that’s something that may be very difficult to do in that kind of environment.

MICHELLE BONDS: Next question, please.

OPERATOR: Our next question comes from Robert King, Washington Examiner.  Your line is open.

ROBERT KING:  Hi, Dr. Frieden. Thanks for taking my call.  My first question is, has this outbreak exceeded the CDC’s initial expectations or projections?  I know that CDC officials previously said earlier this year that they expected limited outbreaks. Has the amount of cases that have happened in Florida over the past few weeks of local transmission, has that exceeded those estimates or anything, or is this in mind with what you expected?

TOM FRIEDEN: So far what we’re seeing is really what we anticipated.  That there would be multiple instances of transmission and some cases of clusters of transmission.  We’ve seen about two dozen infections, about 17 of them symptomatic in the Wynwood area.  That’s pretty much on the mark in terms of what we would anticipate.  We may see more here in Miami Beach simply because it’s a more populated area.

MICHELLE BONDS: Next question, please.

OPERATOR: Our next question comes from Lisa Schnirring with CIDRAP News.  Your line is open.

LISA SCHNIRRING Hi.  Thanks for being available to take questions today.  I just wanted to ask you a little bit more about the challenges with the mosquitoes.  I know there was some concern in Puerto Rico’s outbreak with mosquitoes that were resistant to some of the insecticides.  Do you have any worries about that so far with what you’re seeing there in the Miami area?  Thanks.

TOM FRIEDEN: We’re always concerned about the possibility of resistance.  The more than 90 percent knock down with the product being used, Naled, is encouraging.  In fact, the product has been so effective that it’s been difficult to collect mosquito eggs to do resistance testing.  So that will take some time to occur.  But we know that there is, as far as we know, no natural resistance to the BTIsarvacide being used.  The challenge with this mosquito is it can breed in a bottle cap full of water, it can hatch its eggs.  The eggs can last for more than a year.  They live indoors and outdoors, and eliminating standing water in a place where it rains every day, where there are bromeliad plants and many containers is just extraordinarily difficult.  This is truly the cockroach of mosquitoes and very difficult to get rid of.

MICHELLE BONDS: We have time for one more question.

OPERATOR: Our last question comes from Robert Lowes with MedScape Medical News.  Your line is open.

ROBERT LOWES: Yes.  Thanks for taking my call.  Dr. Frieden, what is your advice for women who are considering getting pregnant as far as travel to Miami-Dade County?  If they’re worried about potential exposure, should they also consider postponing non-essential travel?  In other words, the advice you have for pregnant women, do you also, should that be applied to women who are thinking about getting pregnant?

TOM FRIEDEN: This is something that women should discuss with their physician, and what we’ve said consistently for, certainly for areas such as Miami Beach and Wynwood area and areas around the world where Zika is spreading, is that there are a series of protocols that we recommend for the time to wait after returning, and that’s very much a decision that individuals have to make that will factor into play what they’re going for, how important that is to them, when they’re planning to become pregnant, and what their reproductive plan is.

So I want to thank everyone for participating in this briefing.  We appreciate your coverage of this.  It’s important that people understand the key priorities here, which are that pregnant women avoid travel to places where Zika is confirmed to be spreading that includes countries throughout the hemisphere map or our website as well as these two very specific areas within Miami-Dade County.  We’re also providing openly and transparently information on what’s going on as it happens so that people can make informed decisions about what they want to do about their travel. We’re also fully supportive of the excellent work that Florida is doing to identify and respond to these outbreaks, and to prevent further outbreaks and we’re supportive of them in that effort.  We’re also concerned about people living in these areas.  We know that’s very stressful and we want to make sure that women who are or may become pregnant do everything possible to prevent mosquito bites.  Thank you all very much.

MICHELLE BONDS: Thank you, Dr. Frieden, for joining us today as well as reporters.  For follow-up questions please call the press office, 404-639-3286 or send an e-mail to  Thank you for joining us.  This concludes our call.

OPERATOR: Thank you for your participation.  You may disconnect at this time.


Page last reviewed: July 30, 2016