Dr. Mike Smith (Host): Welcome to Pediatric Insights: Advances and Innovations with Children's Health, where we explore the latest in pediatric care and research. I'm your host, Dr. Mike Smith. And today, we are discussing the evolving measles outbreak in Texas.

Joining us for this insightful panel discussion are Dr. Carla Garcia Carreno, Medical Director of Infection Prevention and Control at Children's Medical Center Plano; and Dr. Jeffrey Kahn, Director of Pediatric Infectious Diseases at Children's Health and Professor at UT Southwestern. Hey, thank you both for joining me today.

Dr. Jeffrey Kahn: Thank you.

Dr. Carla Carreno: Thank you.

Host: So, Dr. Kahn, let's start with you. With the recent rise in measles outbreak, what key clinical signs should physicians be looking for, especially in these early stages?

Dr. Jeffrey Kahn: Well, I think one of the big challenges that we have nowadays is that many practitioners have actually never seen a case of measles, and that actually speaks to the effectiveness of the vaccine. But in the early stages of infection, this is typically 10 to 12 days after exposure. The symptoms are really nonspecific. It can look like the flu, fever, cough is quite prominent, conjunctivitis, or redness of the eyes, coryza, runny nose. These are the features that are typically early in the stages of presentation. And then, the rash begins. And with the rash, the fevers continue. And the rash usually starts on the top of the head, spreads down to the face and to the body and out to the extremities. So, these are clinical clues when it comes to evaluating a child with potential measles.

But I really want to emphasize that history is the most important feature here. And if you only had one question to ask a parent of a child who is presenting with possible measles, that question would be, "Has your child been immunized?" Because if they've been immunized and they've received the appropriate immunizations, then the likelihood of measles is very, very low. So, that's the essential question. And of course, now with the outbreak spreading in West Texas and we know that it's spread to New Mexico, Oklahoma, and now Kansas, whether there's been a known exposure to measles. So, these types of questions can be very helpful. We're trying to sort out whether the patient that you're evaluating is a potential measles case.

Host: Dr. Carreno, do you have anything you'd like to add?

Dr. Carla Carreno: I think Dr. Kahn covered everything I would like to say. For clinicians, one part of the clinical presentation that is also pathognomonic for measles is the Koplik spots that are some lesions inside the mouth and can be seen right at the end of that first phase of the respiratory illness before the rash appears. But otherwise, everything that Dr. Kahn said.

Host: So Dr. Carreno, sticking with you, you know, measles complications can be severe in some cases. What patient populations are at the highest risk for those more severe cases? And when should providers escalate care?

Dr. Carla Carreno: So, measles can have complications even in children or patients without any predisposing conditions for severe disease. And we know that about 20% of the cases, which is one in five, may need hospitalization. The complications that we can see in measles include otitis media in about 8% of the cases, and this can be complicated with hearing loss; pneumonia in about 5% of the cases; diarrhea in about 8% of the cases, which can lead to dehydration; and acute encephalitis, one in a thousand cases, that may result in permanent brain damage.

So usually, the causes of hospitalization are either neurologic or respiratory. Now, there is another complication, which is the blunting of the immune response, T-cell immune response after measles, and that poses to other infections. And a rare but fatal complication that can happen seven to 10 years after the acute infection is the subacute sclerosing panencephalitis.

Measles has a mortality of one to two per a thousand cases. So even though we may see these complications in patients with predisposing conditions, specifically those individuals that are immunocompromised, or the younger kids less than five years of age, or the pregnant women, we can see these complications in previously healthy kids.

Host: So Dr. Kahn, are there any recent updates or recommendations regarding the MMR vaccine that providers should be aware of? And how are current vaccination rates impacting the concept of herd immunity?

Dr. Jeffrey Kahn: So, I'll take those questions in reverse order. We know that to really drive down measles cases and to prevent spread in the community, we need about 95% of the population immunized. And that strategy has worked out very, very well for us in the United States. The last big outbreak of measles was in the late '80s, in 1990. And there were 52,000 cases of measles then, 27,000 cases in 1990 alone. And that experience prompted the second dose of vaccine. And the measles cases numbers reached a nadir in 2004 of 37 cases. So, we went from 27,000 cases in 1990 to 34 cases in 2004. Again, speaking to the power of the immunization strategies here.

At least right here in North Texas, we haven't changed our approach to measles immunization. In the middle of an outbreak, there may be recommendations to lower the first dose of measles vaccination to children six to 12 months of age. Although if children are immunized in that period, that doesn't count towards the two-dose series. So, there are things that we can adjust during an active outbreak, but as it stands right now in late March, we haven't seen any recommendations, at least here in North Texas, about changing immunization recommendations.

Host: Dr. Carreno, with the increase in parents-- at least some parents-- not vaccinating their children, and then now we're seeing the rise in cases here, measles cases, what would you say to a parent about vaccination, being in the position, you are knowing maybe some of their fears, their issues with it? What do you want to say to parents in North Texas?

Dr. Carla Carreno: Yeah. Well, addressing this vaccine hesitancy or misinformation can be challenged. As Dr. Kahn was saying. the strategy of the immunization of our community has worked very well, and this vaccine has been available since the 1960s. So, we need to remind these parents that there is extensive experience.

We've been using it for about 60 years, and it's a safe and effective tool to protect our kids and our population. So, we need to listen to the family's concerns rather than criticizing them. Listen to their questions. Discussing relevant medical literature that addresses how safe the vaccine is. Explaining all the experience with MMR and there's really no associated long-term sequela. There is no link or proven link with autism in multiple.

So, it's important to remind families all of that, those issues, those aspects, listening to them, showing them the medical literature, but also reminding them that the acute measles infection, it's way more severe. The patients may get complications as we were discussing. And it can be fatal.

The American Academy of Pediatrics and the U.S. Center for Disease Control or CDC, they have some toolkits and other strategies that we can use and we can implement in the patient room and discussing with these parents.

Host: Dr. Kahn, anything you want to add to Dr. Carreno's response there? Anything additional you might want to say to a parent?

Dr. Jeffrey Kahn: Well, Dr. Carreno is spot on. The only other thing I would mention is we're starting to see information or lessons, if you will, from the current outbreak that's in West Texas. So, the latest update here in late March is that there have been 400 cases, 41 of those children have been hospitalized. So, it's about 10% are hospitalized. We've already had one death due to measles. So, this is a clear indication that this is a potentially dangerous infection. And we have, as Dr. Carreno mentioned, six decades of experience with the vaccine. And the reason why parents and perhaps grandparents and maybe great-grandparents have never seen a case of measles, is because we've been immunizing and we've almost eliminated, or we got close to eliminating measles from the United States.

So, I think it's important to look at what's going on in West Texas as a lesson for what happens when we have a population of children who are unimmunized.

Host: So, Dr. Kahn, you had already mentioned, at least in early stages, that the way a child presents, it's kind of vague. It can look like many other viral illnesses. And you even also mentioned that there's a lot of physicians practicing now that have never seen cases of measles before. So what key takeaways can physicians apply to their practice to help prevent, diagnose, and manage cases more effectively?

Dr. Jeffrey Kahn: Well, again, I think the first thing is really a thorough history. And there's a particular cadence to the symptoms that appear during measles, and it's pretty consistent. So for example, we're obviously getting a lot of calls about kids with rashes and fevers. And sometimes it can be hard to discern whether this is a potential case of measles or not. But if there is no rash, of course, it could be at the early stages of measles, to ask the questions about exposure, immunizations, and a little bit more information about how long the fever's been going on, what are the associated symptoms.

Once the rash starts, then the questions shift a little bit, and that is that, you know, typically with measles we see fevers increasing during the phase of the rash. So if we have a child who presents with a rash that may look like measles but don't have a fever, it's highly unlikely that this is measles. And also if the rash tends to be vesicular, that's unlikely to be measles.

The other thing I should mention is, as part of the history-taking process is if the child has been immunized, when did they get their last vaccine? Because we know that the measles vaccine, which is an attenuated virus, can actually cause a a fever and a rash. So if the child had received the measles vaccine in the last 21 days, if you're seeing a child with a mild fever and a rash, it's more likely due to the vaccine rather than to wild type measles.

Host: Dr. Carreno, what protocols are used at Children's Health to care for these patients, and is there anything new or different that has been considered since this outbreak?

Dr. Carla Carreno: So as Dr. Kahn was saying, North Texas as of now is not part of the outbreak. So, the DFW area hasn't had any cases related to the outbreak. But we're still preparing, right? So as Dr. Kahn was mentioning, having a high index of suspicion is important. At Children's Health, we are taking all the necessary measures to care for our patients, keeping them safe and keeping their other patients and our staff also safe.

These measures will include prompt identification of potential cases, immediate isolation, if we have a negative pressure room to place the patient in the negative pressure room, or at least a room with closed doors. Giving that potential case a mask immediately upon identification of potential suspicion, and then prompt testing. So, we have to have the clinical evaluation, ask all those questions that Dr. Kahn was mentioning, the timeline, the possible exposures, the immunization, history. And then, we need to establish the patient can be safely monitored at home, or hospitalize the patient, depending on any complications that may be present.

Testing is important and the health department needs to be notified even if we're suspecting a case of measles, so they can do the follow up and the tracking and all the contact tracing. So, it's really important that pediatricians in the community and/or families know that if they have any suspicious for measles, they need to also call the referral center in advance. So, all of these strategies are implemented as feasible because this is one of the most, if not the most contagious illness that there is.

Host: So, you know, this is to both of you, is there anything else you'd like to add? And let's go ahead and start with Dr. Carreno.

Dr. Carla Carreno: Well, the best way that we have to, control measles and prevent measles is by the vaccination, as we were saying. There are no other strategies that will prevent or treat measles. And vitamin A is certainly not a measure that we need to use to prevent measles. So, the most effective way is the vaccination.

Host: Dr. Kahn? 

Dr. Jeffrey Kahn: To follow up on Dr. Carreno's comments, vitamin A has associated toxicities. It's a fat-soluble vitamin and it can accumulate in the liver. And we're already hearing reports from West Texas of children who are presenting with what looks like vitamin A toxicity. And it's important to note that, yes, vitamin A is an adjunct therapy to decrease the likelihood of severe disease due to measles. And it's typically two doses, one dose in two consecutive days.

So, to use vitamin A on a long-term basis, to perhaps think that you're gonna prevent measles, A, it's not going to prevent measles and, B, you may put puni your child at significant risk of vitamin A toxicity. And it just seems to me that maybe this is another indication how sideways things have gone that not only are we now reminding the medical community what measles looks like, we're also having to remind the medical community what vitamin A toxicity looks like.

Host: Dr. Kahn, Dr. Carreno, this was fantastic. Thank you so much for your time with us today and for coming on the show.

Dr. Jeffrey Kahn: Well, thank you.

Dr. Carla Carreno: Thank you for the opportunity.

Host: And thank you to our audience for listening to Pediatric Insights: Advances and Innovations with Children's Health, where we explore the latest in pediatric care and research. For more information, visit childrens.com. If you found this podcast helpful, please rate and review or share the episode and follow Children's Health on your social channels. Stay informed and stay healthy.