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Measles outbreak sparks fear of resurgent diseases

March 16, 2014 at 8:00 AM EDT
Recent outbreaks of measles on both the East and West Coasts highlight a larger story about how infectious diseases that had all but disappeared in the U.S. are now reappearing. Why are some of these diseases showing back up? Hari Sreenivasan speaks with Stephen Morse, a professor of epidemiology at the Mailman School of Public Health at Columbia University, about the reasons for these outbreaks.

HARI SREENIVASAN: We want to turn now to another story that’s gotten a lot less attention this week — recent outbreaks of measles on both the East and West Coasts. It’s part of a larger story about how infectious diseases that had all but disappeared in the U.S. are now reappearing. For more, we’re joined by Stephen Morse, he’s a professor of epidemiology at the Mailman School of Public Health at Columbia University. So nearly 20 cases of measles in New York, but nationwide the number of measles cases according to the C.D.C. was up three times last year. So why is this happening?

STEPHEN MORSE: Well measles is vaccine preventable and so to a large extent it’s because of people who are not being immunized or are too young to be immunized. Normally we start recommending immunization at about one year. But for example we had an outbreak last summer in Brooklyn largely because the decision in those communities was to wait before immunizing the children and vaccinate them later, and so some of the younger children got infected.

Diphtheria strikes unprotected children Protect your child with toxoid--Toxoid prevents diptheria : Chicago Department of Health.

Find out more about diseases making a comeback

HARI SREENIVASAN: And so how much of this is related to people coming in from other parts of the world and then combining with those populations here that aren’t immunized?

STEPHEN MORSE: In most cases that’s what’s happening. There are a number of places in the Netherlands, for example, and the U.K. and elsewhere, where for various reasons there are communities, various religious communities for example, that refuse immunization. They just don’t want to be immunized, and occasionally a case will break out there in that population, someone will come over here and introduce it. And most of the population is immunized and protected but not everybody.

HARI SREENIVASAN: So what are some of the other infectious diseases that kind of keep you up at night? When I was looking this up that scarlet fever cases are up at a 24 year high in the U.K. I mean obviously in this global and connected world people are carrying infectious diseases along with their luggage as they travel to and from.

STEPHEN MORSE: Well the one that worries me the most is the one we don’t yet know about. Because you know all of these have popped up; scarlet fever has been with us a long time. My mother was hospitalized with it, 60 or 70 years ago and it was very common then. And we don’t understand why it waxes and wanes. And the streptococcus bacterium, of which it is a member, is with us all the time, strep throat for example, but some of the different forms seem to have their own variable patterns, we don’t know why. And then of course we have meningitis which is also bacterial, but an unusual type for which we do not have an effective vaccine yet in this country, although we’re going to be licensing that soon.

HARI SREENIVASAN: So I want to ask, how much of this is kind of our own success sort of leading to a certain type of complacency? You said your mother had scarlet fever, you had first hand knowledge of it, you knew what to be fearful of. Most of us have never seen polio or measles in our lifetime immediately.

STEPHEN MORSE: That’s absolutely true and I think for the diseases that are vaccine preventable, and more and more of them are. I had measles when I was a child and in fact a vaccine was developed a few years later, so it’s possible now to be immunized and not ever have to experience what so many of us went through earlier. But for the vaccine preventable diseases very often it’s just those people who are afraid to be immunized, afraid to have their children immunized for whatever reason and depending on their neighbors to protect them. measles is extremely transmissible so you really need a very high level of immunization to protect people. So the complacency there is the fact that we don’t see the threat quite the way we did 50 years ago or perhaps even 25 years ago. There are others that are in the environment, that in other species, occasionally get to human being through human activity such as land use changes, agriculture and then they spread through trade. SARS, the outbreak we had starting in China and Hong Kong and spreading throughout the world in 2003 is one example. Right now we have a related situation that has not spread as widely, the Middle East Respiratory Syndrome — MERS — which is similar to SARS, but has not yet been spreading throughout the world. But all of these are out there in nature and I think complacency has something to do with it, but also the actions that we ourselves may take without realizing their effects.

HARI SREENIVASAN: Alright Stephen Morse from Columbia University, thanks so much.