According to the Centers for Disease Control and Prevention, there have already been more than 700 measles cases in the United States so far this year – more than double the number of cases reported in all of 2024.
While there have not yet been any cases reported in Missouri, there are currently identified outbreaks in 25 states.
Nathan Koffarnus, the assistant bureau chief for Bureau of Communicable Disease at the Missouri Department of Health and Senior Services, spoke about the history of measles in the United States and what people need to know about how the disease spreads to keep themselves – and others safe.
Missouri Health Talks gathers Missourians’ stories of access to healthcare in their own words.
Nathan Koffarnus: Prior to 2000, really prior to the advent of modern vaccination, which the first vaccine was licensed in, I believe, 1963.
So, you know, prior to that, we'd have been talking about half a million cases a year would be pretty typical in the United States.
And then cases dropped really precipitously after the advent of vaccination, and the current vaccine is better than the initial one.
It's a two-dose series, and it's very effective, good track record. A single dose of measles vaccine will protect 93% of people that receive it. So, if 100 people get the shot, 93 of them would never be at risk for developing measles.
"This is one of the most transmissible viruses that we have."Nathan Koffarnus
You add that second dose in there that that number bumps up to 97.
So very, very effective shot, and that's why we've really been successful in eliminating it in the US, and why it doesn't spread very far historically, you know, once it does get introduced.
The real problem moving forward is that vaccination rates have been tumbling, and so I would hope a lot of listeners would be familiar with the concept of herd immunity. It got talked about a lot during COVID.
If you have more than 95% of a community or a group or the public as a whole vaccinated, it basically leaves so few people that are susceptible that while you might get a one-off case or two like we've had in the past, it just doesn't have anywhere to go. There aren't enough unvaccinated people out there that are still susceptible.
The problem is right now, our vaccination rates in Missouri have dropped down to about 90% so we're below that threshold.
First thing people need to know is that between when you get exposed – so, when you come into contact with the virus and when you actually get sick – ranges between seven to 14 days. So, one to two weeks out after exposure, when you first become ill.
And so, that gets really challenging, because you may not have any idea you were exposed. It can be really hard to trace back. It's a long, a long gap between exposure and illness.
This is also – people need to bear in mind, this is one of the most transmissible viruses that we have.
So, if an individual with measles were to walk into a room with 10 other people that that hadn't been vaccinated, had no immunity – natural or vaccination immunity – we would expect nine out of those 10 people to come down with measles.
So, it's extremely, extremely transmissible. It can live in the air for up to two hours.
So, you could have a situation where somebody was contagious in a classroom, you're not even in the classroom at the same time as them, but maybe a period or two later, you come into the same room, and you get exposed.
But as far as what illness looks like, it starts off very generically, you could expect a high fever, and then what we call the three C's.
Which are cough, coryza, a fancy word for runny nose and conjunctivitis, which is a fancy word for irritated eyes.
