Press Briefing Transcripts

Update on measles outbreaks throughout the United States

August 21, 2008

MODERATOR: Good afternoon, and thank you all for holding. At this time, your lines have been placed on listen-only until we open up for questions and answers. Please be advised today′s conference is being recorded. If you do have any objections, you may disconnect at this time.

I would now like to turn the call over to Mr. Curtis Allen. Please go ahead, sir.

CURTIS ALLEN: Yes. Thank you for joining us today. I′m Curtis Allen; I′m in the office of media relations at CDC. Today we have two speakers: Dr. Anne Schuchat – that′s A-n-n-e S-c-h-u-c-h-a-t. Dr. Schuchat is the director of the National Center for Immunization and Respiratory Diseases at CDC. We also have Dr. Jane Seward – Jane J-a-n-e, Seward S-e-w-a-r-d. Dr. Seward is Deputy Director, Division of Viral Disease in the National Center for Immunization and Respiratory Diseases. Dr. Schuchat will open it up with a few remarks and then turn it over to Dr. Seward, who will give you a broader overview of today′s subject, which is measles outbreaks throughout the United States.

So with that, I will turn it over to Dr. Schuchat. Dr. Schuchat?

DR. ANNE SCHUCHAT: Thank you, Curtis. Hello. You know, I spoke with many of you a few months ago about the measles situation in the United States and our concern, and what I need to do today is reinforce that we really do have a concerning situation this year in the United States.

We have had more cases so far in the United States this year than in any year since 1996. CDC has received reports of 131 cases so far this year. And today′s MMWR is updating the national picture and giving some details about two recent outbreaks that occurred in the states of Washington and Illinois. Those outbreaks involved many children who were home-schooled and whose parents had philosophical or religious beliefs that influenced their decisions about vaccinating their children.

At the national level, I am concerned about our situation because this year is so different, and I want to make sure parents are aware of that. Every year the US experiences importations of measles from other countries, from travelers going abroad, and from people from other countries visiting us here. But what′s really different this year is that once the measles virus is imported here, we are seeing it spread to many more people. Most of that spread is in people under 20, in children. And some of those cases are in kids who were just too young to be immunized; they′re under 12 months. But many of the cases of measles we′re seeing this year are in children who are eligible for vaccination but who have not been immunized because of their parents′ decisions.

And my key messages to you today are to make sure that parents know that measles is still around and that it is a serious disease and that it can be prevented through vaccination. We′ve been really lucky to have low levels of measles and other vaccine-preventable diseases in the United States, but our children can still get measles; and they can still spread measles to other people, including those too young to be immunized or those who can′t be immunized for medical reasons. I really want to make sure parents have this information so that they can help keep their children healthy and safe.

I′d like to introduce Dr. Jane Seward, who′s going to give you more details on the US situation and who can answer the questions that you have.

DR. JANE SEWARD: Thank you, Anne. Just by way of introduction, measles is a highly contagious disease that can result in serious complications and death. As Dr. Schuchat mentioned, due to a very successful measles vaccination program, we interrupted endemic measles transmission or achieved measles elimination in the United States, and this was declared in 2000. However, despite huge achievements in global measles control and elimination around the world, there are still an estimated 20 million cases of measles that occur around the world. And so the United States remains at risk of implications of measles, and that situation is likely to continue into the future.

This year, from January the 1st through January the 31st, 2008, CDC has received 131 reports of concerned measles cases, the highest number of cases reported for the same period since 1996. Cases have been reported from 15 states and the District of Colombia. The 131 cases includes seven outbreaks, and these account for 81% of the cases. The largest outbreak with 30 cases has occurred in Illinois.

Of the 131 cases, 17 of them were importations; eight of these were foreign visitors to the United States who came down with measles during a visit; and nine of them were US residents who traveled abroad and acquired measles overseas. These implications came from a variety of countries, but the majority of them came from Europe, where there are large outbreaks of measles ongoing in Switzerland, Italy, and a number of other countries.

Over 90% of the 131-case patients were unvaccinated or had unknown vaccination status, and the rest, just a few – five – had received one dose and six had received two doses of MMR vaccine. Considering the 112 unvaccinated or unknown vaccination status cases, 16 of these were infants too young to be vaccinated. Those infants are usually protected through herd immunity in their communities, but they were exposed to measles in their communities and became infected. One case was in somebody born before 1957; the remaining cases, or 95 cases, were eligible for vaccination, and of those two-thirds of them, or 63, were unvaccinated due to their own or their parents′ philosophical or religious beliefs.

As Dr. Schuchat mentioned, the majority of the cases, 80% of the US resident cases, were less than 20 years of age, and a great majority of those were children whose parents chose not to have them vaccinated. Fifteen patients were hospitalized, including four children less than 15 months of age. Fortunately, we haven′t had any deaths this year.

I think the cases this year highlight that, although we′ve done an excellent job with our measles vaccination program in the United States, we do have an ongoing risk of implication of measles from around the world. That risk is highest in people that are unvaccinated. People that are unvaccinated can transmit measles to others, including infants who are too young to be vaccinated or people with medical reasons such as cancer who cannot be vaccinated. It′s important in this country to maintain our high levels of vaccination that′s been so successful in limiting measles to relatively low numbers over the last decade. And we′d like to remind parents that if children go back to school, whether or not they attend school in schools or a home school or whether they attend daycare, this is a good time to be considering their vaccination status for measles to protect them from acquiring this disease. Thank you.

CURTIS ALLEN: Okay. We′ll open it up for questions now.

MODERATOR: Thank you. At this time, if you would like to ask a question, please press star (*), one on your touchtone phone. Once again, star (*), one to ask a question.

Our first question comes from Mandy Gardner with Health Day. Please go ahead.

MANDY GARDNER: Thanks for taking my question. I′m seeing two numbers for the number of cases in Illinois. It said 32 I think in the press release, but Dr. Seward just said 30. I′m wondering –

DR. JANE SEWARD: I was talking about an outbreak that′s linked together. There are 30 cases in one outbreak in Illinois and two additional cases, separate cases that are not linked to those. One was somebody who returned from Switzerland and became a case, and there was another case far removed from that outbreak. So in total in Illinois there were 32; 30 of them were clustered into one large outbreak.

MANDY GARDNER: Thank you.

CURTIS ALLEN: Next question, please.

MODERATOR: Thank you. Our next question comes from Amy Burkholder, CBS News.

AMY BURKHOLDER: Yes, hi. Thank you. My first question is how young can kids get vaccinated because we′re seeing that 12 months is the youngest age, but then we also see six months for kids traveling?

DR. JANE SEWARD: Yes, that′s a great question. Under routine conditions, the age recommended for vaccination for measles is 12 to 15 months. But because of the risk of acquiring measles through international travel, it′s recommended that infants 6 to 11 months receive an early dose of measles or MMR vaccine to protect them during travel. When they return and after their 12-month or their first birthday, they should, in addition, receive two additional doses.

AMY BURKHOLDER: Oh, okay. I′m sorry; we had one follow-up question as well. Can you help us sort of clarify importation? Of the 131 cases, how many were here? How many came from abroad?

DR. JANE SEWARD: Seventeen came directly from abroad, and another 99 were associated with those importations.

So associated means they – you know, say an initial case from an outbreak, an outbreak in San Diego that we just described earlier in the year, a little boy returned from Switzerland, and then there were 11 additional cases from his case. So those outbreaks are all called importation associated because they occurred due to an importation. We had 15 cases that had an undetermined source of infection, but that′s not surprising. We consider they probably likely were linked to an importation that wasn′t reported or that in fact didn′t occur in the country.

AMY BURKHOLDER: Thank you.

CURTIS ALLEN: Next question, please.

MODERATOR: Thank you. Our next question comes from Daniel Denune, WebMD.

DANIEL DENUNE: Thank you. I have two questions; one is a very quick one: What is the current vaccination coverage rate for the measles vaccine? And the other one is more complicated: Can you go into more detail about what are these religious and philosophical beliefs, specifically those that you investigated in Washington and Illinois? Thank you.

DR. JANE SEWARD: Well, taking your first question first, we′ll be announcing our coverage levels for 2007 in a couple of weeks. But in children 19 to 35 months, 92% of children had an MMR vaccine in 2006. And in school-aged children, due to – you know, partly due to our school requirements I think, we′ve always had very, very high coverage of MMR vaccine with at least one dose, coverage levels being 95% or greater throughout the country.

Your second question, we have not in the course of this outbreak so far done a detailed investigation around the philosophical or religious beliefs. We′re aware that these people are choosing not to vaccinate because of those beliefs. In San Diego, where an outbreak occurred earlier this year, they are conducting a more detailed investigation to understand parents′ beliefs concerning this vaccine.

CURTIS ALLEN: Follow-up, Dan?

DANIEL DENUNE: Just one last question: Why do we – this is somewhat unrelated, but why do we need to have such a high coverage rate? You′re saying that it does remain tame, blocking the endemic coverage. We′re talking about more than 90% in first dose and more than 95% in second dose. Why so high and can you illustrate that perhaps with what′s going on in the UK?

DR. JANE SEWARD: Yes, very good question. Just to clarify, the 95% was with at least one dose. It′s not a 95% two-dose coverage estimate for us. Measles is highly infectious. It′s one of the most infectious diseases that we have. And so if ten people or, you know, a hundred people are in a room that haven′t had measles and a case of measles comes in and starts coughing and they′re infectious, 90 to 95 of the people in that room will come down with measles. So because of its highly infectious nature, we need very high levels of population immunity, 95% approximately, to interrupt transmission.

In the United Kingdom, just a couple of months ago in June the Health Protection Agency there declared that measles had reestablished endemic transmission in their country, and that is in the phase of coverage levels of 80 to 85%. In Italy, where there is a large outbreak of measles going on in the country – they′ve had more than 2,000 cases in the last 12 months, and a number of those cases have been imported into the United States – their national coverage level with one dose of MMR vaccine is reported at 88%. In Israel, where they report national coverage levels of about 93% or higher, they are still experiencing an outbreak of more than a thousand cases in a population that objects to vaccination. So I think this highlights that even with extremely highly vaccine coverage levels as high as we have in the United States, we could have sizeable pockets of people similar to what′s occurring in Israel that may result in much larger outbreaks of measles than we are having now. And as our coverage levels fall, we are in danger of having much larger outbreaks and transmission.

DANIEL DENUNE: Thank you very much.

CURTIS ALLEN: Next question, please.

MODERATOR: Thank you. Our next question comes from Fred Pastor, Miami Herald. Please go ahead.

FRED PASTOR: Hello. I wonder if you could tell me whether the vaccination rate is dropping in the US and, if so, if it is because of the fear of vaccines in autism.

DR. JANE SEWARD: That′s a very good question. To our knowledge – and, again, we will be releasing our latest coverage estimates in children 19 to 35 months for 2007 in a couple of weeks. But from our data from last year, there isn′t any indication that coverage is dropping, but I would remind you one of the reasons we′re concerned is that, you know, coverage levels in children 19 to 35 months in 2006 really reflects practices of immunization of several years before that. So we may well be having some drops in coverage, but we may not be able to measure that for a couple of years. We don′t know, but we′re concerned.

FRED PASTOR: I see. Thank you.

CURTIS ALLEN: Thank you. Next question, please. Next question, please.

MODERATOR: Our next question comes from Mary Ingle, the Los Angeles Times. Please go ahead.

MARY INGLE: Thank you. I was wondering whether it has achieved – measles has achieved endemic transmission in any other countries besides the UK that has returned to endemic transmission. And also whether there has been any deaths in any of the European countries that have been seeing outbreaks.

DR. JANE SEWARD: Yes. Well, I would say measles is endemic in Switzerland at the moment and likely endemic in Italy as well because those outbreaks have been going on for more than a year. A number of countries in Europe have not achieved elimination of measles. Of countries that have achieved and are now endemic again, I think the United Kingdom is one of the two that I know about. Two deaths have been reported in Europe, one in Italy and one in the United Kingdom this year. Both those children happened to be immuno-compromised children, meaning they couldn′t be protected directly through vaccination, but they would have been protected had there been high immunity in their population through high vaccine coverage. Europe has had in the last, you know, three or four years have had additional measles deaths. So I think some of those have been in healthy children.

Encephalitis, which occurs at a rate of one to three cases in every thousand measles cases, that occurs – that can occur at any time. I mean, you can never tell with any one measles case which is going to be the unlucky one that has a very severe complication like encephalitis. And so, fortunately, we haven′t seen any cases of encephalitis this year so far, but we could. We′re seeing a number of cases of pneumonia, one of the other serious complications of measles. And Europe, many European countries have reported a number of encephalitis cases this year.

CURTIS ALLEN: Next question, please.

MODERATOR: Thank you. Our next question comes from Gardner Harris, the New York Times. Please go ahead.

GARDNER HARRIS: Hi. Could you just – I understand that there is also some sort of neurological problem that can result from a measles infection many years down the line. Can you talk about that? And can you also talk to us about the risks that non-vaccinated children pose to other children? Is the vaccine, you know, 100% effective? Do these parents who choose not to vaccinate their children endanger the children who do get vaccinated? Thanks.

DR. JANE SEWARD: Certainly. You′re correct, measles can lead to infections, can cause sclerosing subacute panencephalitis years after a measles infection, 10, 15 years after infection, a very, very serious illness that can occur. And we started seeing those cases in the past; a number of those cases occurred in the decade following the resurgence of measles that we saw from 1989 to 1991. Your second question about the risk that unvaccinated persons pose to their communities, that′s absolutely correct. Communities that have a number of unvaccinated or a sizeable number of unvaccinated people are at risk as well of developing measles. And that includes – that′s because of their chance of coming into contact with one of their neighbors or friends who may have measles. And that includes children who are less – you know, too young to be vaccinated, people who are vaccinated. And that′s why we have had some cases in vaccinated children this year, and people with medical contraindications.

GARDNER HARRIS: How many children this year among vaccinated, those who have already been vaccinated?

DR. JANE SEWARD: Eleven cases this year were vaccinated; five had received one dose and six had received two doses of MMR vaccine. I think the other way of looking at those data is that measles vaccine, one dose of measles vaccine, provides 95% protection. And so for every hundred people exposed to measles, only five of them will develop it and 95 will be protected. For two doses of measles vaccine, it′s 99% effective. And so for the six cases we saw in two-dose vaccinated people, there have probably been about 600 people exposed that did not become cases.

GARDNER HARRIS: Thanks so much.

CURTIS ALLEN: Our next question, please.

MODERATOR: Thank you. Our next question comes from Mike Stobbe, the Associated Press.

MIKE STOBBE: Hi. Thanks for taking the call. Doctor, did you say of those 15 hospitalized cases what specifically they were hospitalized with?

DR. JANE SEWARD: No, I didn′t. We know that some had just very high fever and dehydration. We know some had pneumonia. But more details on that we don′t have available at this time.

MIKE STOBBE: Thank you.

DR. JANE SEWARD: Our next question?

MODERATOR: We have no further questions.

CURTIS ALLEN: If there are no further questions, thank you for joining us today. If you have additional questions, you can call the press office here at CDC, 404-639-3286. There will also be on the website a transcript of this briefing at www.CDC.gov/media. And that should be posted within a couple of hours. Thank you very much for joining us.

MODERATOR: Thank you. And this does conclude today′s conference call. We thank you for your participation.

END

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U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES