Can US Measles Outbreaks Be Stopped?

The US is experiencing its worst year for measles in over three decades, with more than 1,300 cases in 40 states as of July 16. Cases were almost as high in 2019, putting the country’s measles elimination status at risk. Six years ago, health officials were able to stop the spread. But amid growing public backlash against vaccines, many of the tactics used then may not work now.

Measles elimination means there has been no continuous transmission in a country for longer than 12 months. That almost happened in the 2019 outbreak, which largely affected Orthodox Jewish populations in New York City and some surrounding counties. In fall 2018, US travelers returning from Israel tested positive for measles. The disease quickly spread throughout close-knit communities, especially among children, due to low vaccination rates. While the statewide measles vaccination rate for school-age children was 98 percent the previous school year, vaccination coverage in schools in the outbreak area was only 77 percent. Because measles is highly contagious, a 95 percent vaccination rate is needed to protect a community from the disease.

As a result, the majority of measles cases occurred in individuals 18 and under, nearly 86 percent of whom were known to be unvaccinated. Some of those people developed severe complications, including pneumonia, and nearly 8 percent were hospitalized.

The current surge is being fueled by an outbreak that started in an undervaccinated Mennonite community in West Texas. Cases have since spread to other Texas counties, New Mexico, and Oklahoma. Two children in Texas with no underlying conditions and one adult in New Mexico have died this year as a result of measles. All were unvaccinated.

“There are definitely parallels. What we saw in New York was very much the result of years and years of spread of misinformation and disinformation around the safety of vaccines,” says Neil Vora, executive director of Preventing Pandemics at the Source Coalition and previously a medical epidemiologist at the Centers for Disease Control and Prevention who helped respond to the 2019 outbreak.

Cases eventually burned out in New York after a months-long effort that included both traditional public health approaches and policy changes at the local and state level.

“You need to take the first case seriously, because it's like kindling. You never know when that fire is just going to break out,” says Oxiris Barbot, the current president and CEO of the United Hospital Fund, who served as New York City’s health commissioner from 2018 to 2020.

As the disease spread, Barbot realized the city health department would need to go to the source of transmission, largely the Orthodox Jewish schools in affected neighborhoods. Working with school administrators, they reviewed vaccination records to identify unvaccinated or under-vaccinated children. Following an exposure, those children were prohibited from attending school and childcare for 21 days, the incubation period for measles. Similar measures were taken in some counties outside the city.

“It took a lot of staff time, a lot of leg work,” Barbot says. In one school, a contagious child led to more than 25 infections in other students and further spread outside the school. She says the health department was “heavily involved” in making sure schools were abiding by the quarantine measures.”

Health officials also worked to combat misinformation. A Jewish anti-vaccine group called Parents Teaching and Advocating for Children’s Health, or PEACH, distributed a 40-page anti-vaccination booklet titled “The Vaccine Safety Handbook” that contained conspiracy theories and inaccurate information, including the debunked claim that vaccines cause autism. In response, the city health department mailed booklets that provided accurate and religiously relevant information about vaccines to thousands of households in affected neighborhoods and launched a campaign to combat vaccine myths.

“We were consistently delivering the same message that was backed by science and that gave our community partners the legitimacy with which to engage their family, their friends, and their neighbors in countering the myths and disinformation that was being shared,” Barbot says.

When those efforts weren’t enough on their own, New York City used its public health authority to increase vaccination rates. In April 2019, about six months after the first cases appeared, Mayor Bill de Blasio declared a state of emergency, requiring individuals living, working, or going to school in affected zip codes to be vaccinated against measles. Those who didn’t comply could be fined. In Rockland County, unvaccinated people under the age of 18 were banned from public places for 30 days.

That summer, the New York legislature also changed statewide vaccination requirements to remove religious exemptions, which were previously allowed. The change applied to public, private, and religious schools.

As a result of the efforts in New York, tens of thousands of vaccine doses were administered. In one affected Brooklyn neighborhood, the percentage of children who received at least one dose of MMR vaccine increased from less than 80 percent to 91 percent between October 2018 and September 2019. A modeling study by a researcher at Columbia University found that without these measures, numbers of infections and hospitalizations could have been 10 times higher.

Those efforts won’t necessarily map neatly onto the current measles outbreak. Vaccine requirements would likely face pushback in conservative states like Texas, especially since mistrust around vaccines has risen since the Covid-19 pandemic. (In fact, in May, Texas lawmakers passed a bill to make it easier for parents to seek vaccine exemptions for their children. That law goes into effect September 1.) “Different approaches are going to have to be tailored for the unique needs of those specific areas. It's not a one-size-fits all approach,” Vora says.

In Texas, the Department of State Health Services carried out a comprehensive paid media campaign that included online, broadcast, billboard, and on-site ads in businesses in two phases from March to June to encourage measles vaccination. The department was especially focused on areas where measles was spreading and areas at greater risk of an outbreak. This was in addition to the department’s usual vaccination campaigns, a spokesperson tells WIRED via email.

Zach Holbrooks, executive director for the South Plains Public Health District in Texas, which covers Gaines, Yoakum, Terry, and Dawson counties, says his department had mobile vaccine and testing clinics operating in all four counties from February until May, when cases started to decline. Gaines County, which has reported more than half of the cases in Texas, is no longer an active outbreak county as of July 8.

“Anytime we saw cases popping up where they hadn't been before, we would get with our state partners and deploy resources to those areas,” Holbrooks says. “All we can do is supply opportunities for people to get screened or vaccinated. It's really up to them to take advantage of those services.” In Gaines County, 313 people were vaccinated as part of those efforts, although Holbrooks says he was hoping to see more.

His district tried to get the word out about vaccination with a mobile billboard truck that drove around the region. They also worked with the state and the CDC to translate vaccine communication into German to target the Mennonite community.

“The messaging was out there,” Holbrooks says. But he thinks lingering mistrust from the Covid-19 pandemic has led to more people rejecting vaccines and public health guidance. “Sometimes attitudes and feelings about vaccines are pretty hardwired in people, and it's hard to overcome the negative beliefs that they have.”

It’s also been challenging to get people to comply with the 21-day quarantine rule. He received reports of kids with measles being out in public with their parents. “A lot of people didn't take it seriously,” he says of the quarantine period.

Another hurdle is that many people are traveling for summer vacations, which can easily spread disease and make it harder to trace the chains of transmission.

There are signs, however, that disease spread may be slowing down. The number of new measles cases has been declining in recent weeks, according to the CDC. Still, with pockets of low vaccination across the country, transmission could continue throughout the rest of the year, and future outbreaks are likely. Building back trust in vaccines and public health will take time.

Barbot says consistent messaging at the federal, state, and local levels is one step in that direction. While current US Health and Human Services secretary Robert F. Kennedy Jr. has tepidly endorsed the measles vaccine, he has also made the false claim that protection from the vaccine wanes quickly and has promoted vitamin A as a treatment for measles. While vitamin A is often given to children with nutritional deficiencies who get measles, it doesn’t kill the virus.

“It’s not too late,” Barbot says. “With an all-out effort we can avoid losing that [elimination] status.”