In response to the current measles outbreak, public health officials and the media have struggled to understand who anti-vaccination parents are. Where do they live? (Orange County.) What types of schools do they choose? (Private, sometimes charter, and especially Waldorf.) Do they vote Democrat or Republican? (Both.) What kind of kale do they eat? (Organic.)
From several studies published in the past decade, a picture is emerging: Unvaccinated children today tend to be well-off, white, and live in suburban areas. Intriguingly, that demographic profile couldn't be more different from that of the last big U.S. measles outbreak, from 1989 to 1991. Then, low vaccination rates were an issue of poverty and low access to health care. Now it's a matter of choice.
The epidemic in 1991 was eventually squashed thanks to massive efforts by federal and state health authorities to increase vaccine access to the poor. The solution to today's outbreak won't be as straightforward, experts say.
"My concern from a public health perspective is that this is maybe a little bit of a harder group to target than in 1991," Melissa Stockwell, assistant professor of pediatrics, population, and family health at Columbia University Medical Center, told BuzzFeed News. "When it was an issue of access to health care, we knew we could get in, we could offer vaccinations, and we could get kids vaccinated. It wasn't that the parents were against it."
When the measles vaccine debuted, in 1963, there was an immediate disparity between who got immunized and who didn't, according to Elena Conis, professor of medical history at Emory University and author of Vaccine Nation. "Immunization promotion campaigns encouraged middle-class families in particular to vaccinate their children for their own sake," Conis told BuzzFeed News by email. Soon measles was a disease of poor minorities living in the inner city.
Over the next few decades, the vaccination gap between rich and poor only widened.
The 1989–1991 outbreak caused, all told, more than 55,000 cases of measles, at least 11,000 hospitalizations, and 166 deaths. Most of those infected were unvaccinated black and Latino children under the age of 5. They lived in inner city areas, concentrated in Los Angeles, Houston, Chicago, New York City, and Philadelphia. As the California Department of Health Services determined after the outbreak, "This was an epidemic among unimmunized, economically disadvantaged minority infants and young children."
In the aftermath of the 1991 epidemic, the culprit was clear: Poor people needed better access to vaccines. In 1993, Congress approved the federal Vaccines for Children program, which paid for vaccines to children whose parents couldn't afford them. Measles vaccine coverage has been at or above 90% ever since. And largely because of this measure, public health experts say, by 2000, measles was declared eliminated in the U.S.
"[The program] played a major role in realizing that we had gaps in our immunization system, and access was one of the biggest issues," Saad Omer, professor of global health, epidemiology, and pediatrics at Emory University, told BuzzFeed News. "We have made huge, huge progress in making vaccines accessible to underprivileged populations."
But that approach won't work against the current measles outbreak. After a notorious research paper published in 1998 showed a (now disproven) link between the measles, mumps, and rubella vaccine and autism, some parents began opting out of immunizing their kids.
In recent outbreaks, so-called "zero-dose" children — children who do not receive any vaccines at all — "tend to belong to relatively larger families with a college-educated mother who is suburban," Omer said. "Refusals [to vaccinate] have tended to be of a higher socioeconomic status."
Likewise, low vaccination rates in California child-care centers have clustered around private schools in some of the state's wealthiest areas: Los Angeles and Orange counties, San Francisco, and San Diego. One child care center in Los Angeles — the Manhattan Beach Nursery School — had a measles vaccination rate as low as 36%. In contrast, federally funded Head Start programs, which serve low-income areas, have the highest vaccination rates, at roughly 96%.
Rich and middle-class kids are probably also the ones getting sick. The data hasn't come in yet for the current measles outbreak, but according to CDC data from last year's spike — which eventually spread to 644 cases across 27 states — over 85% of those who got sick and were unvaccinated had declined vaccines because of religious or philosophical reasons. Only 6% were unvaccinated due to "missed opportunities," or not coming in contact with a doctor who could advise them to vaccinate.
With today's outbreak hinging on the choices of parents, some experts say that it's time to limit those choices.
"If states were to have a more rigorous exemption process," Stockwell said, "my opinion is that we would have fewer children who are at risk."