HORTON (host): This week health workers also tracked a growing outbreak in New York…The CDC reported 60 new cases of measles in the city. Local officials are desperate to stop the spread.
LANTRY (host): This isn’t the first time New York has fought the virus. Maggie Green explains how we once came close to wiping out measles — and why we fell short.
GREEN: Signs printed on red, orange and yellow parchment hang on a wall in the Museum of the City of New York. They were printed about a hundred years ago, but in big bold letters, they feature names familiar to us today:
JACOBS Smallpox, diphtheria, scarlet fever, whooping cough, meningitis…
GREEN: And measles. Rebecca Jacobs co-curated the exhibit Germ City at the museum. She says these quarantine notices warned people to stay out of buildings where people had these infectious diseases. If someone tried to go into one of these spaces, the city would fine them $25. That’s about 650 today–
JACOBS And people would be forbidden under penalty of law to enter or leave the premises without special permit from the health officer.
GREEN: For hundreds of years, quarantining the sick was the only way public health officials could handle infectious diseases like the measles. Jacobs said some people were kept in their homes, some were sent to hospitals and others were sent to islands like Staten Island, and Hoffman and Swinburne Island nearby.
JACOBS And might’ve been very close to New York City, but it must’ve felt very far away.
GREEN 4: By the mid-twentieth century, measles in the U.S. was spreading like gangbusters. Stephen S. Morse is an epidemiologist at Columbia. And he says the number of cases grew every year.
MORSE Documented, 500,000 children had it at the same time. Probably, it was more like one to three million.
GREEN: But not every case was reported to doctors, because the measles was so common, and so contagious–10 times more contagious than the flu. Measles viruses can live for up to 2 hours on a contaminated surface, and the microbes are very good invading a susceptible person’s body through the air in a closed space. Morse says imagine if someone with measles were to walk into a room full of unvaccinated people.
MORSE Probably 90% at least probably all of them will catch measles with a few minutes of exposure.
GREEN It’s that fast.
MORSE It’s very catching.
GREEN: But here’s the thing about the measles. Once someone gets sick, they’ll never catch it again. In the 1930s, a researcher named A.W. Hedrich realized as more people in a community got the measles, they became immune. And fewer people in that area got sick. He called this “herd immunity.” Wan Yang studies how diseases move through populations at the Columbia School of Public Health. She says in order to stop a disease like the measles, not everyone needs to be immune. But you do need vaccines, and a magic number.
YANG With a 95 percent vaccination rate, the majority of them have been immune, so you no longer have continued transmission.
GREEN: Ninety-five percent is our magic number. Scientists realized in order to stop the spread of measles, 95 percent of people would have to be immune. And that became possible with the invention of the measles vaccine in 1963. Luther Terry was the surgeon general at the time.
TERRY (ARCHIVAL) As increasing numbers of children are vaccinated, we will be well on the way to eradicating a disease that down through the centuries has killed millions of children.
GREEN: As the number of vaccinated kids went up, the number of measles cases fell drastically every year until the U.S. reached that magic 95 percent number in 2000. The World Health Organization said measles had been eradicated from the United States. So why did the measles come back? Epidemiologist Yang says there are two reasons. First, as more people move into big cities, that five percent of unvaccinated people becomes a bigger number. Second, in a more crowded space, those people will start to interact more.
YANG And you also have these high population density that is favorable for the transmission of the virus.
GREEN: Like in New York. This year’s measles outbreak is the second highest number of cases nationwide since the disease was eradicated. But, unlike in the 1800s and early 1900s, quarantining infected people isn’t our only option. We have our magic 95 percent number, if public health officials can convince people to get vaccinated. Maggie Green, Columbia Radio News.