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Q&A: Measles And Vaccinations

Dr. Edwin P. Ewing, Jr. / CDC

Dr. Edwin P. Ewing, Jr. / CDC

NOTE - The article was edited 2/5/15 to change the answer in the second question to 400 kids die per day worldwide from measles.

Public health officials say a recent outbreak of measles, linked to Disneyland in Southern California, is serving as a wake-up call to many parents to vaccinate their kids. But there are are still many questions out there about the disease and how immunizations work.

Capital Public Radio spoke with Dr. Dean Blumberg, an associate professor at UC Davis and Chief of the Pediatric Infectious Diseases division, to answer some of these questions.

*Note: Some of the questions and answers have been edited for clarity.



Q: Just how contagious is measles?

A: Measles is transmitted a couple of different ways, one is that you cough or sneeze and it forms a droplet. We’re familiar with that -- from getting the cold or the flu. The droplet forms and if you’re close to that person, you breathe it in or somehow it lands on you and you get infected.

Measles can be transmitted in other ways. It can be aerosolized. So the cough or sneeze can lead to smaller particles. It’s so small that it circulates in the air, it takes an hour or two for gravity to have it land into a surface. Someone who’s infectious can walk into a room, cough or sneeze, leave the room. An hour or two later, somebody else can walk into the room, [the particles] are still in the air and that person can breathe it in and they can get infected.

I would say it’s one of the most contagious diseases known to mankind.


Q: How dangerous is measles?

A: Most people think of measles as being a fever and a rash and some older people might remember having that as a child and they might think of it as a rite of passage. But I’ve seen the complicated cases and measles can be a real killer. Before we vaccinated against measles in this country, we had 500 deaths every year. We would have 1,000 people who would’ve complications from measles, like encephalitis, inflammation of the brain, that would result in brain damage. And even now, 400 kids die every day from measles worldwide. So it’s a really dangerous disease and it can be a real killer. It really should be avoided.


Q: Even people who were vaccinated, some might still get it? Why does that happen?

A: The measles vaccine works about 95 percent of the time. You get one dose, you get about 95 percent immunity. You get two doses then that other 5 percent has 95 percent chance of becoming immune. So two doses is about 99 percent effective in terms of preventing measles. 99 percent sounds really high, but it’s still not 100 percent and if you expose enough vaccinated people, you’re going to get 1 percent of them getting measles. Measles is so highly contagious that before there was vaccination, for every case of measles, nine-out-of-ten people exposed would end up getting measles. It’s that contagious.


Q: For those who’ve gotten the vaccine, do they need a booster?

A: The only way to tell for sure if you’re immune is by getting a blood test. I had one, because I’m a health care provider, and health care providers are deemed to be at higher risk of measles. I don’t have my vaccination records, although I’m pretty certain my parents made sure I got all of my vaccines. But since I don’t have my records, I don’t have documentation of two doses of measles vaccine. I had a blood test, which showed I’m immune. If I’m an adult, who is not particularly at high risk, I would feel comfortable with one dose. If I’m an adult that is at higher risk, for example in the healthcare field or traveling internationally, then I would want two doses, and kids, of course, should get two doses.


Q: There are parents who’ve initially vaccinated their kids with the initial dose at 12 to 18 months of age. The second dose isn’t recommended until 4 to 6 years old. Because of the recent outbreak, should parents go ahead and get the second dose before the recommended timeline?

A: No, not unless there’s something else going on such as international travel, where there’s increased risk of exposure, I think I’d wait until 4 to 6 years of age.


Q: Who are the people who can’t get shots for medical reason?

A: Children who have weakened immune systems, either the vaccines won’t work on them or they may have extra side effects. Some can’t get vaccinated because they’re too young. Children less than a year of age, don’t respond very well to measles vaccines, that’s why it’s given at 12 to 15 months. Those children are very vulnerable and really need to rely on the people around them to be protected so that they don’t get exposed.




Q: You mentioned that this year is the first time in 35 years that the rate of personal belief exemptions (PBE) went down?

A: Years ago the immunization branch of the California Department of Public Health shared with me some slides and the slides go back to 1979. They showed personal belief exemptions (PBE) and personal medical exemptions (PME) -- those are true contraindications to vaccination.

I didn’t mean to say that it went a straight up line, but generally, it had been going up almost every year. Not every single year, once in awhile, it went down by 0.1 percent or something like that. But almost every year had been an increase over the past 35 years. So, it went from 3.15 percent to 2.54 percent PBE. To me that seemed very significant, it wasn’t just a little blip, that’s a 20 percent decrease.


Q: Is this decline attributable to the law that was recently passed? The law requires that parents speak with a health care provider and have that health care provider sign a form in order to get a personal belief exemption for vaccines.

A: It’s a very similar approach that was used in Washington state. In Washington state, the first year they had a similar law in effect, they saw a 25 percent decrease, so it does seem consistent with their experience.


Q: Is California unique in allowing exemptions?

A: Many states allow PBEs, many states allow religious exemptions. Some states don’t, some states only allow medical exemptions. California is one of 14 states that allow the PBEs.


Q: How does California compare to other states in terms of the percentage of people who claim exemptions?

A: There’s been several studies that have looked at the process for which parents claim exemptions for their child and then the overall immunization rates. And these studies are very consistent, states where it’s easier for parents to opt out of immunizations, have higher rates of exemptions. The ones that have more strict or harder processes to follow for the parents, those states have higher immunization rates.


Q: Did California’s PBE policy pave the way for outbreak?

A: Well, I’m not exactly sure what role PBEs have played. What I can say is that, in the last outbreak of pertussis, the 2010 outbreak, scientists researched how PBEs affected pertussis rate. They found that when you get clusters of PBEs, you get clusters of pertussis, so it did seem like a direct correlation. I can’t say how that’s working out with measles, but I would suspect the same is true. The issue with the PBEs isn’t just the overall rate of 2 to 2.5 percent of people opting out, that’s an average. But if you look at the rates by county, it clusters and when you look within counties, within communities such as schools, you can get very high rates of PBEs.

For measles, you need somewhere between 93 to 94 percent overall immunity to prevent an outbreak, to prevent further transmission. You can imagine a school with 10 percent or 20 percent PBEs that really creates the conditions for which you can get continuing transmission of measles.

In general, private schools have higher rates of PBEs. The last data from the California Department of Health shows that the overall rate of PBEs was 2.54 percent for the state. It’s 2.3 percent for public schools, 5.3 percent for private schools. It’s more than twice as high in private schools.

Almost all of the outbreaks that have occurred in California over the last five years or so have been related to PBEs in some way. And about 80 to 85 percent of those whose vaccination status is known, and have gotten measles in california, are unvaccinated either because they’re too young to be vaccinated or they’ve chosen not to be vaccinated. I think that’s pretty clear that there is a relationship. In the current outbreak, of the 34 whose vaccination status is known, 28 are unvaccinated. So that does seem related.


Q: Should we rethink our policies for PBEs?

A: It’s a really difficult question to answer. On the one hand, I really want everyone vaccinated. And I’m confident that’s the right decision. I want 100 percent of people vaccinated. On the other hand, I don’t want to be forcing people to do something they’re uncomfortable with, people need to be comfortable with that, so that’s the difficulty


Q: Talk about the Immunization Information Clinic at UC Davis. (Parents can go to the clinic to get their exemption forms signed?)

A: In California, we’ve had increasing rates of PBEs, almost every year they’ve been going up, and we felt a lot of that was out of convenience. California is one of the easiest states for parents to get a PBE. They just had to sign a form. Washington state passed a law that changed that process, they had a similar process to California. But they changed it so that instead of the parent signing it themselves, they have to go to a health care provider, and then the health care provider would educate them about the vaccines, and vaccine-preventable diseases. The health care provider would sign off as well as the parent. And they saw a 25 percent reduction in PBEs the first year that went into effect. So I was all for that in California, we also passed a similar law. During the hearings that led up to that in the legislature, many parents objected to this law saying that it was unfair to them. They said they would not be able to find somebody, a health care provider to sign off on the form. I didn’t think that would be a problem, but in response to that, I said if the law passed, we’ll set up a clinic. Specifically to sign the form.


Q: Is that a situation parents encountering? Where they would have difficulty finding a provider who would sign the form?

A: Many healthcare providers are frustrated with parents who don’t vaccinate their children because it takes a lot of time for them to talk with them and they feel that vaccination, immunization is really one of the backbones of preventative care and making sure that children are healthy. And if the parents don’t agree with them about vaccinating their children, they feel that there’s a very wide philosophical difference in terms of care and they feel it’s not a good fit for their practice. So some pediatricians and family practitioners really don’t want to see those kinds of patients, they don’t feel comfortable with those kinds of patients for various reasons. Some parents know this and say they can’t find somebody who will take care of their child.


Q: How does your clinic strike that balance?

A: I’m all for parental rights. Parents, obviously, should do what they feel is right for their child. And many parents have researched the issue and they’ve decided that they don’t want to vaccinate their child for various reasons, they use sources that I don’t think are very good, and their conclusion I don’t agree with, but I respect their right to make that decision. And I really respect them for spending so much time researching it because they care for their child. So if they can’t find somebody to sign the form, they usually Google it and they find that we’ve got this clinic and they can come into the clinic. We basically agree to disagree and I sign the form. It’s not confrontational at all, if they don’t want to get their child vaccinated or want to postpone it, then I sign the form, it’s not a big deal.


Q: What do you tell people who are anti-vaccine?

A: The style of the conversation can vary depending on what the parent wants. For example, there might be a parent who comes in saying I’ve researched it, I’m against it, here’s the following three reasons I’m against it. You can sense, they’re not really open, they’ve made the decision. That’s a very brief conversation, I’m not gonna try to argue with them or change their mind.

And then there’s the parent on the other end of the spectrum, who might come in and say I’ve got some concerns. They say, I’m not sure what to do, I’ve heard from some friends, or my in-laws that I should do this or do that and I’m not quite sure. And we go through for every thing that they’re worried about in relation to vaccines.

So, for example, if they’re worried about autism. Years ago, a British doctor claimed that the MMR vaccine was associated with autism, I can talk about that specific study that he came out with, I can talk about how that study has been retracted that he’s been discredited, he’s actually been disbarred from practicing medicine. Because of the concern related to that, millions of children were studied in several other well-done studies. There is no scientific evidence that vaccines are associated with autism. And if they’ve got other issues, related to why the vaccine schedule is the way it is, or additives with vaccines, I’m happy to talk to them about those issues too.


Q: Have you successfully changed minds?

A: Very few. I think most of the people who come to our clinic are frustrated that they couldn’t get someone else to sign the form and they’ve already made up their mind. But we’ve had a couple of parents who’ve come in and after I’ve talked to them, they remained undecided and I told them if they changed their mind, just come back.


Q: What is the current rate of exemptions in CA?

A: Over the last 35 years, the PBEs in California, has just risen, almost every single year. Every once in awhile, there’s a year that it goes slightly down, but it’s gone from less than a half percent to over 3 percent. It’s gone up over six times in the last 35 years. And that’s why this bill was passed, to try and address that issue. And it just went into effect last year, and for this school year, the 2014 to 2015 school year, I’m really pleased that it actually went down. So it went from 3.15 percent down to 2.54 percent, well it seems related to the timing of the law so i would attribute it to that.




Q: What was your first thought when you heard about people getting measles at Disneyland?

A: I was really worried about that because Disneyland, you’re going to get international visitors there, and most of the outbreaks we’ve had in California have been related to international visitors recently. Measles is more prevalent in countries that have a lower vaccination rate than in the U.S. Most of cases in California were related to importations from the Philippines, we’ve also had cases related to importation from Japan, and Europe because some countries like France and Switzerland, have a relatively low immunization rates from measles. So you get a visitor from one of these international areas, they come to Disneyland and then you get people who might get infected and then they go home and then it goes everywhere.


Q: Many young doctors haven’t seen measles. What are doctors doing in terms of training?

A: Many are trying to educate physicians and other health providers to be on the alert for measles. We’re telling healthcare providers, if they see a patient with a fever and a rash, think measles. It doesn’t have to be measles, there are several different things that can cause rashes, but at least have that on your radar. And then if there’s any question, call someone with more experience, who have seen measles. During my fellowship training in Los Angeles that was during the 1989 to 1991 outbreak of measles, I saw a lot of measles cases. Several of us who are older and more experienced know measles because we’ve seen it before. But the younger generation of healthcare providers, we just say if you’re not sure, give us a call.


Q: What should schools be doing, particularly where there are cases reported?

A: I think this measles outbreak is kind of a wake-up call that parents should know the immunization rates at the schools their children are going to. If they have high PBEs in those schools, I would like parents to be the ones to take the lead on this. I can’t go in and tell people what to do, I’d be happy to, but I don’t have as much credibility as another parent. If you get parental peer pressure to talk to other parents, to make sure that they get their kids vaccinated, that creates a safer environment for their child. Even if their child is up-to-date on their vaccinations, they’re not 100 percent protected and so having those around them vaccinated helps protect their child too.

Q: Has there recently been an uptick in patients getting vaccines/boosters because of the recent outbreak?

A: I’ve heard anecdotally that this has been a wake up call for some parents who may have been lackadaisical about getting their kids immunized, or may have been on the fence, and just not worried about it. Some parents have come to me and said I don’t want to vaccinate my kids now, they’re too young, I’m worried about it, I’ll wait until they’re older and maybe traveling.  Because they probably won’t get exposed to anything unless they travel. [The recent outbreak] just proves that’s not true. You don’t have to travel to get these diseases, and so it’s important to get immunized on time.


There have also been questions about the vaccinations in the 1960s. Those who received vaccinations from 1963 through 1967 received killed measles vaccines that were not effective.

Here’s what the CDC has to say about people who received the vaccines in the 1960s and prior to 1957:

Do people who received MMR (Mumps, Measles, Rubella) in the 1960s need to have their dose repeated?

Not necessarily. People who have documentation of receiving LIVE measles vaccine in the 1960s do not need to be revaccinated. People who were vaccinated prior to 1968 with either inactivated (killed) measles vaccine or measles vaccine of unknown type should be revaccinated with at least one dose of live attenuated measles vaccine. This recommendation is intended to protect those who may have received killed measles vaccine, which was available in 1963-1967 and was not effective.

Why are people born before 1957 exempt from receiving MMR vaccine?

People born before 1957 lived through several years of epidemic measles before the first measles vaccine was licensed. As a result, these people are very likely to have had the measles disease. Surveys suggest that 95% to 98% of those born before 1957 are immune to measles. Note: The "1957 rule" applies only to measles and mumps—it does NOT apply to rubella.


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