An Israeli flight attendant who contracted measles has been comatose for over a week following a flight from New York City to Tel Aviv in late March. The 43-year-old woman reportedly developed encephalitis—swelling of the brain—a potentially deadly, severe complication of a virus that was once thought to be eradicated in North America, but is now experiencing a national resurgence.

"She's been in a deep coma for 10 days, and we're now just hoping for the best," Dr. Itamar Grotto, associate director general of Israel's Ministry of Health, told CNN. She has reportedly been placed on a respirator in an intensive care unit at Meir Medical Center, after checking herself into the hospital with a fever on March 31st.

An infected passenger likely exposed the woman to measles while she worked an El Al flight on March 26th. It's believed that she did actually get the vaccine as a child, but while vaccination is highly effective at preventing the virus (93 to 97 percent, depending on whether or not a patient gets one or two doses of the vaccine), there's still a small chance that even inoculated people will get sick anyway.

In 2000, health officials declared measles eliminated in the United States, thanks to the widespread introduction of a vaccine developed in 1968 and still used today. Yet measles persists in close-knit and insular communities—the Amish in Ohio, for example, Minnesota's Somali populations, and Eastern European enclaves in Washington state—that don't commonly vaccinate children. The current outbreak can be traced to Brooklyn's Orthodox Jewish communities, where anti-vaxxers have waged targeted misinformation campaigns: Between January 1st and April 11th, the Centers for Disease Control and Prevention confirmed 555 cases of the virus in 20 states, the diagnosis rate rising nearly 20 percent in the week after April 4th.

According to the Washington Post, a man responsible for spreading measles from NYC to other parts of the country seems to have been exposed to the virus in Israel, before traveling to Brooklyn in November. In March, he drove to Michigan on a fundraising trip, staying with members of Detroit's Orthodox community throughout his travels. He reportedly felt sick upon arrival, and saw a doctor, who misdiagnosed his symptoms—a cough and a fever—as bronchitis and prescribed antibiotics. The man then developed a rash, which the doctor initially chalked up to an allergic reaction before putting the pieces together and tipping off the health department.

Officials worked with the local Hatzalah members to track down patient zero, who reportedly believed himself to be immune to the disease because he'd had it before. Since arriving in Detroit, the man came into contact with hundreds of people in the Orthodox community—not only in their homes, but also at synagogues, yeshivas, kosher markets, and a pizza parlor. As a result, 39 people came down with the highly contagious virus.

Health officials in Brooklyn, Rockland County, and Westchester County have been working to counteract the spread of the disease. Rockland County declared a state of emergency in late March, banning unvaccinated people from public spaces including schools, houses of worship, shopping centers, and restaurants. (Parents of unvaccinated children subsequently sued.) Earlier this month, Mayor Bill de Blasio declared a public health emergency in NYC, compelling four zip codes in Brooklyn (11205 in Clinton Hill; 11206, which encompasses parts of East Williamsburg, Bushwick, and Bed Stuy; 11211 in Williamsburg; and 11249, which stretches from the Williamsburg/Greenpoint border down to the Brooklyn Navy Yard) to either vaccinate, or face fines.

This, too, prompted a lawsuit, but the city is moving forward (while also walking back an initial threat of jailing violators). On Monday, it shuttered a Williamsburg yeshiva that refused to furnish vaccination records for its students. The situation is serious: As of April 15th, the city health department had confirmed 329 measles cases, 44 of which cropped up in the last week. According to Health Department Commissioner Oxiris Barbot, at least two children at the yeshiva had measles.

"We don't take this measure lightly," Barbot said at a press conference. "We recognize that school closure can potentially present hardships for families and that's not our intent; but if a school is unable and unwilling we will definitely close them ... in this situation it's critical that schools play their part in excluding students who are unvaccinated."