Telebriefing Transcript: CDC Update on Outbreak of Yellow Fever in Brazil, Vaccination Recommendations

Press Briefing Transcript

Friday, March 16, 2018

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

OPERATOR: welcome and thank you for standing by. at this time all guests will remain in listen only mode for the duration of today’s conference of at the end of the presentation we’ll open up question and answer session and today’s conference is being recorded. If you have any objections, you may disconnect at this time. I will now like to turn the conference over to Benjamin Haynes, Thank you sir, you may begin.

BENJAMIN HAYNES: Thank you Karen and thank you all for joining us on the current outbreak of yellow fever in Brazil and the release of a new CDC Morbidity and Mortality Weekly report which describes 10 cases of Yellow Fever in unvaccinated travelers to Brazil in the first months of 2018. We are joined by Dr. Martin Cetron Director of CDC’s Division of Global Migration and Quarantine coauthor of the report. He along with lead author Dr. David Hamer principle investigator of GeoSentinel and lead author of the report and Dr. Lyle Petersen, Director of CDC’s Division of Vector-Borne Diseases will address questions after the briefing. I will now turn the call over to Dr. Cetron.

MARTY CETRON: Good afternoon and thank you, Benjamin. Thanks to all of you who are joining us for the teleconference. We’re here to talk about the yellow fever outbreak in Brazil which is an important public health issue and one that has the potential to affect Yellow fever virus Is found in tropical and sub tropical areas in South America and Africa the virus is transmitted to people by the bite of an infected mosquito. In the last two years Brazil’s yellow fever outbreak has expanded significantly moving closer to popular tourist destinations near the coast and in major urban areas like Rio de Janeiro and San Paulo. We have also had recent reports of yellow fever cases and deaths in travelers . In light of this expanding outbreak we’ve updated advice to travelers , should not go to yellow fever hot spots in Brazil unless they’re vaccinated. Health officials in Brazil recently confirmed more than 920 cases of Yellow fever including more than 300 deaths, during this outbreak that began late 2016. Cooler temperatures resulted in declining cases during 2017 winter season. Transition began again with the warmer weather that came last late fall and wintertime resulting in a second wave of the outbreak that is ongoing now. The MMWR that was released here this morning describes yellow fever cases in travelers to Brazil including those reported to Geosentinel, this is a global surveillance system for travel related illness among international travelers and migrants. In just the first few months of 2018, at least ten unvaccinated travelers from Europe and South America contracted Yellow fever in Brazil and other possible cases are under investigation. Eight of these travelers were infected on the island in Isla Grande In Rio de Janeiro state and all four reported deaths were in travelers who had visited Rio Grande. Highly unusual and suggests that Isla Grande is a exceptionally hot spot for yellow fever virus transmission. All cases identified by Geosentinal and other authorities reported to date have occurred in unvaccinated travelers .Vaccine is the best way to prevent yellow fever. We recommend that unvaccinated travelers in all unaffected areas of Brazil get vaccinated at least ten days before their trip. For the most up-to-date information about the outbreak in Brazil, please see our travel notice which can be found at The travel notice includes a map of the affected areas as well as information about yellow fever and our comprehensive advice for travelers including actions for mosquito bites. There’s also information there on the website about where travelers can get yellow fever. Right now the one U.S. license yellow fever vaccine yfvax is out of stock. An alternative stammerill which is comparable in effectiveness is available instead. The challenge as some you have may not is that only a limited number of clinics in the United States have Stamaril approximately 250 across the country, which is reduced from the 45 clinics. for many travelers  a clinic with stammerill will be in a reasonable distance but some may need to drive significant distances to reach one of these authorized clinic with the vaccine. Appointments may be limited because of high demand. We know this has been and will continue to about he inn inconvenient and frustrating for travelers. We have created an easy to use map detailed list on the website showing which clinics in each state have Stamaril. In light of the expanding outbreak in Brazil, we encourage travelers to take the extra time and extra steps necessary to get vaccinated before the trip.

Before we get to questions I want to reemphasize people who have never been vaccinated against yellow fever should not travel to areas of Brazil affected by the outbreak particularly Isla Grande the hot spot of e la grande. We appreciate your role in sharing this information with our travelers and with your readers. We now look forward to answering any questions that you have and to repeat, we are joined on the line by Dr. Lyle Petersen of CDC’s Division of Vector Borne Diseases and Dr David Hammer the principle investigator for geosentinel and lead author of the report, who is the first author of this report.

BENJAMIN HAYNES:  Thank you. Karen, we are now ready for questions.

OPERATOR: Thank you. At this time if you would like to ask a question please press star and one and record your first and last name clearly when prompted. Again please press star and one if you like to ask a question at this time. Please be reminded you will be allowed one question and one follow up.

Our first question comes from Mike Stobbe with the Associated Press, sir, your line is open.

MIKE STOBBE: hi. Thank you for taking my call. Can I ask first of all how many U.S travelers go to Brazil each year? How many people do we think might need these shots. And my follow up is if you could say a little more about the history of the travel notice. how is this changing? Shots previously recommended but now you are saying they are not only recommended but do not go to these areas if you haven’t had the vaccination.

MARTY CETRON:  Thanks. I will take the latter part first and say clearly two things are going on. the e pigilotic in Brazil this outbreak is expanding significantly over the last two years and that expansion has moved both south and east and now encompasses areas that were previously not recommended for vaccine. So to give a rough feel, the population at risk prior to this outbreak living in yellow fever transmission areas in Brazil was approximately 5 million. that number is probably more than 30 million now with this new expansion. This new expansion has also got close to the urban settings in big states and coastal areas that are visited by a lot of tourists. So the expansion has actually meant that the vaccine recommendations that we’ve had in our notices, if you look at them over time, has been expanding to encompass the dynamic change this outbreak is representing, the increase in risk. Also with the number of travel-related cases and deaths the intensity of transmission with regard to traveler’s risk is somewhat unprecedented. In that regard we’re strengthening the message and want people to be aware of new areas of risk and strengthening the hesitation someone may have because of the challenge of getting vaccines. We don’t want them to hesitate and think i will go without it, can’t hurt, my friends have gone and nothing happened. It is highly unusual for geosentinal to see these clusters of cases in fact, last 20 years haven’t had any reported this way. So we’re strengthening both the advice “be protected or don’t go” and know that the change has increased in terms of risk. So that’s your second question. First question was about volume. In 2017, 2.2 million passenger journeys occurred from Brazil to the U.S. most of these occur during December and January. And 75% of these travelers arrive at five airports in the U.S. which are Miami, JFK, Orlando, Atlanta and Houston. a large percent, over 70% of those incoming travelers  are Brazilian nationals coming here to visit or returning here to visit family and relatives. So the rough break down of that is about 30%. The to Brazil is also about 2.2 million. the break down in proportion of who goes there versus who is coming in at any one point in time may vary a little bit in terms of citizenship. The point is the same. This is a highly connected place in the world to the United States where several million-travel journeys are happening every year. and there are peak travel time frequently corresponding with peak transmission times of this outbreak.

BENJAMIN HAYNES: Next question please.

OPERATOR: thank you. our next question from Maggie Fox of the NBC news. Your line is open.

MAGGIE FOX thanks i have one question and a follow up. can you talk about yellow fever in context to Zika you learned a lot about how people carry back to the rest of the world and trying to follow up on Zika and we know yellow fever is transmitted the same way. can you help us explain to people how this relates to what we know about Zika transmissions. and can I please follow up.

MARTY CETRON: sure, Maggie. I will start and turn it over to really. Let make one point about the current yellow fever outbreak. Right now this still what we call an epi-zootic which is the outbreak in Brazil is largely being spread by non-aedes mosquitos. Sort of the forested cylcle of yellow fever is spread by different mosquito species — and what’s being reported out of Brazil to date largely suggests an expansion of the epizootic. The concern, obviously, and the reason why there’s massive vaccine campaign in Brazil to immunize the urban population is to prevent the introduction yellow fever into the urban mosquito population. The Zika virus was being spread by the aedes mosquito and we’re much more receptive in certain part of our country because we have Aedes Aegypti mosquitoes. This is still a farest related outbreak. There’s listens to Zika that may apply. There’s clear distinctions. Both are Zoonotic viruses and vector born viruses. The benefit we have with yellow fever is we have an available vaccine and race is to protect people who could be exposed. We didn’t have that tool for Zika and that’s a very important distinction. Let me turn it over to Lyle to add any other comments on this.

LYLE PETERSEN: Thank you Dr. Cetron. Maybe I can provide a little shorter answer. There’s basically two kind of mosquitos that spread the yellow fever virus. One is forest-dwelling mosquitos so people go where the virus is circulating in the forest and its usually spread between non-human primates like monkeys and these forest-dwelling mosquitos and when people come into those environments they could get exposed. That’s what happening often this Isla Grande it is a forest reserve people go and can get infected. also could be spread by the Aedes Aegypti mosquito this is the same mosquito that spreads Zika virus as well as Chikungunya virus and a couple of others. it is an urban mosquito. it lives around people in cities. So it could spread the virus from person to mosquito to another person. That’s what we fear could potentially happen. Although, in the continental U.S. the last kind of this urban transmission happened well over a hundred years ago. We’re not too worried about yellow fever being transmitted in the United States because we don’t have these forest-dwelling mosquitos for one thing, and the other thing is that we learn from Zika that even though many travelers came in with Zika virus infection there were very limited transmission in the continental United States. Even though Aedes Aegypti mosquitos were found commonly in the United States. There’s potential for yellow fever virus to be introduced into the southern United States spread in but we don’t think it will happen if it did it would be very limited in scope.

BENJAMIN HAYNES: Maggie, you had a follow up question.

MAGGIE FOX: there has been reports that in current rumors about the vaccine are spreading on what’s up and other social media down there. Do you all know anything about that?

MARTY CETRON:  We probably reading the same reports that you have. and I think to get more insight into the specifics and what’s being done locally in that setting, would be best to contact folks on the ground in Brazil. I think our source of information is the same thing you’ve been reading.

BENJAMIN HAYNES: Next question.

OPERATOR: thank you. Our next question comes from Jason Beaubin of NPR your line is open.

JASON BEAUBIN: Hey, thanks for doing this. I have two questions. If you are just going to Rio or just going to San Paulo those states are on your list of recommended areas, but if you are just going for business, going into the urban area, how much risk do you really have?

MARTY CETRON:  We can’t quantify the risk other than to say it is markedly increased over what it has been. and the data, the dynamic nature of the outbreak and ability to know precisely where the virus is at any point in time is pretty limited. to give you a feel of proximity, monkeys were dieing off in the parks areas on the outskirts of the San Paulo city. There were primate deaths in the san Paulo zoo. so it wouldn’t be very hard to walk to an area where there’s this forest-related transmission. And I would not want to the take a trip down there now without the protection of a vaccine since we have a vaccine. it’s just a risk that I wouldn’t take. and you know, i think that’s kind of what we’re trying to say. There is certain amount of unpredictability in that had has moved quite close and at the time somebody goes situation could be different both better or worse. So we can’t give a block by block granular level of the risk scenario but it is markedly increase over what it’s been traditionally.

JASON BEAUBIN: And my second question – Obviously Brazil has been aggressively attempting to protect people over the years. what’s your sense what’s going on with this outbreak that it continues to be apparently expanding.

MARTY CETRON: I don’t think we understand all of the factors behind the reemergence of Yellow Fever in  Brazil. Historically the activity back to 1942 before you saw urban outbreaks of Yellow Fever. We think these emergence as a holy triad of infectious disease factors around the pathogen. factors around the host including vulnerability or susceptibility to infection. and factors much more less understood have to do with the milieu of the circumstance. The ecologic factors, cultural factors, behavior, mobility, forestation. Isla Grande, as Dr. Petersen pointed out, is a  sortof a forested island that has become an attractive tourist destination. So changes in mobility and travel patterns where People are coming into contact with greater contact with forested areas is a fact yoorp. factors. There’s all sorts of potential intersections why it has expanded the way it does. I don’t think we fully understand it. They bear more research and you’re right there’s been an aggressive campaign in the last few years with this reemergence to urgently immunize 23 million people, the target populations in these new transmission areas. so it’s a race against the virus to get the population protected by immunity and we need to learn more about why this is happening.

BENJAMIN HAYNES Next question from Donald McNeil of the New York Times your line is open.

DONALD MCNEIL: thank you. besides this press conference what is the  CDC doing to spread the word on this? I’m asking because while this press conference is going on i’m looking at one travel adventure site and trip advisor and lonely planet and not seeing anything about yellow fever on any of these sites. it’s all go visit beautiful Isla Grande there’s nothing saying you might die. is CDC going do more than hold this press conference and how do you know it will work.

MARTY CETRON: Yeah so we are actively doing more. this is one of many steps. we have a media campaign and partner outreach and we understand where the populations are living in the U.S. we are doing large communication very targeted outreach campaign. we’re also trying to get a better understanding of the vaccine coverage rate of travelers  to Brazil and coming in from Brazil. That activity will be ongoing this month. And we’re trying to knit together with geosentinal and other surveillance networks to have a better understanding of risk. Also members of Lyle’s team, and I’ll Let Dr. Peersen speak to this, have been consulting with Brazilian authorities about their vaccine campaign and other type of things. there’s a lot going on more than just this press conference but donald, your point is well taken, one of the reasons for doing this, like you I have a sense there’s a disconnect between what people understand about the new yellow fever epidemic in Brazil, the degree to which we’re connected to Brazil, and the intersection of the yfx stock out in the I share your concerns. and we’re going to continue to push hard on this issue.

DONALD MCNEIL:  Are you reaching out to the travel agencies and the others who are encouraging people to have fun down there rather than expect somebody to be on a  CDC website looking it up.

MARTY CETRON:  yes we’re doing direct outreach to the travel industry partners, booking partners, airline partners, et cetera. clearly it’s not enough right. These ten case that’s reported with south America and European travelers  are sort of a cold wake up call that we don’t want to see this happen to  we also n want to make sure physicians that are seeing the large incoming population of Brazilian visitors,et cetera, if they get a fever after spending time in these risk areas need to be thinking about yellow fever which is not necessarily first and foremost on the mind of U.S.physicians, even infectious disease specialists.

We want people to get diagnosed early, properly treated with the kind of supportive therapy that are available. there’s a lot of provider physician outreach too. We started the outreach about the shortage more than a year ago and we’re behind the efforts to get it importation of stamerill into the United States or wouldn’t be a totally absence of vaccine in the U.S.while their plants are shut down.

BENJAMIN HAYNES: Next question please.

OPERATOR: thank you. Our next question comes from lynne Petersen of trends and medicine. ma’am, your line is open.

LYNNE PETERSEN: So what are you doing to improve the supply of the vaccine?

MARTY CETRON: So as I mentioned, when it was apparent, some of you may know that for two years leading up to the stock out the vaccine had been rationed somewhat by the manufacturer. YF manufacturer. we were aware of those issues as they shared them. manufacturer. when they first indicated there would be a stock out no more in production until a new plant was built and coming online to do that we worked with the dod, with the FDA, with Sanofi and others to make sure there would be a continuous supply of yellow fever vaccine in the you may know Sanofi makes Stamaril made in france. with authorization with the fda we worked with them to bring in the vaccine in the U.S.the clinics chosen were chosen based on calculations of how many IMV clinics they could support and then we helped design a system that made sure that the largest areas where travelers  were coming from would be served. That the availability stamerill people wouldn’t have to drive places to get access to the vaccine and we’d continue to monitor the vaccine to see the up tick. they indicate that there’s plenty of stamerill available to continue to bring into the meet whatever demand that we would have. What you see is also globally what other countries have done in settings of global shortages of Yellow Fever vaccine around massive urban outbreaks like the one in Angola which required  use of a global stockpile.there had been studies that documented the effectiveness of fractional dosing. that is to divide the full dose into partitions and you can stretch it and get five doses out of one.  CDC particularly folks in Dr. Petersen’s group have studied the effectiveness and duration of that immunity in providing protection. Theres a recent paper in the New England Journal that highlighted that you could also fractionate existing Yellow Fever vaccine supplies and still get protective coverage just some of the efforts being done. More planning is ongoing in this space.

BENJAMIN HAYNES: We have time for one last question.

OPERATOR: Thank you. Next question is form Naseem Miller from Orlando Sentinel your line is now open.

NASEEM MILLER : Thanks for taking my question. I was wondering, with Orlando we’re expected to have 500,000 visitors coming through the airport this year. And also have these theme parks. Just for the readers what is the level of worry as far as the Yellow Fever coming back here or potentially spreading? And number two – You addressed this a little bit – How well prepared do you think our Emergency room doctors are for expectations – – is there easy way to diagnose.

MARTY CETRON:  I think to highlight what Dr. Petersen said and i will turn it back to him to speak to the diagnosists and so on. we think that the circumstances are really different. the environment is different in the U.S. we’re not expecting that there would be large widespread out breaks of yellow fever across the U.S. even in areas that have Aedes Aegypti. Even looking at Zika and that pattern what it looked like. That doesn’t mean to say we won’t have imported cases, we could. doesn’t mean to say there might not be small area where’s local transmission could occur through Aedes mosquitos that is a possibility. but we do not anticipate there will be large scale outbreaks like the ones you are seeing in Brazil which have, you know, a much higher chronologic suitability as the same big outbreaks. I think the emergency room doctors, Orlando has second highest it volume of travelers  from Brazil 400,000 in 2017 is you are well aware of this issue and we do think that continuing to educate providers to make a diagnose, report cases, and support the people who are sick is going to be key. I will let Dr. Petersen talk about some of the diagnosistic capabilities that exist at the local level.

LYLE PETERSEN yeah, thanks Dr. Cetron. we actually do have very good diagnosistics for yellow fever. they’re available through CDC here in my division. and so, what any physician that sees a patient with possible yellow fever can contact their local health department who can then collect the specimens and transfer to CDC for diagnosistics. we have good diagnosticdiagnostics. we have good diagnostic in the united states. We have the Aedes Aegypti mosquito here and throughout southern Florida so there’s small be possibility if the transmission if the case is reported. However there’s low risk. risk. We learned with Zika, thousands of people came to the United States with Zika virus which is carried by the same mosquito – The aedes aegypti mosquito and only saw very limited transmission down in parts of southern Texas and in the Miami area. So, we will be on the lookout for any cases that appear. We are encouraging physicians with clinically compatible cases to test for it. We are ready and available to test those specimens.

MARTY CETRON: Okay. let me just close this out by kind of giving you the bottom line again. There is an expanding number of hot spots in Brazil where yellow fever virus is being transmitted. These are a-typical areas in large states that have not previously seen this amount of viral activity in decades. Including a specific hot spot on Isla Grande where these travel related cases are reported and they have caused fatal illness in those settings. Bottom line is, CDC does not recommend people travel to these hot spots in Brazil without the protective benefit of Yellow Fever vaccine. It may be harder to get but it’s worth the extra effort and make sure you’re vaccinated before you go.

BENJAMIN HAYNES: thank you doctors for joining us today. in addition to today’s mmwr release  CDC traveler website has launched a new yellow fever web page with latest updates and information and resources for travelers  and physicians including a clinic locator tool to find the nearest vaccine clinic can call 404-639-3286 or e-mail Thank you for joining us.

OPERATOR: Thank you, this concludes today’s conference you may disconnect at this time.


Page last reviewed: March 20, 2018