From the NYT:
The Ukraine connection
The infections have not been confined to a particular ethnic group. The country is at war with pro-Russian separatists on its eastern border, distrust in government is high, and rumors about vaccines are rife — one of which began when a 17-year-old died of unrelated causes after getting a shot.
The Ukrainian government also rejected cheaper Indian and Korean vaccines in favor of European ones, but they cost more than the government could afford, Dr. Larson said.
But the real problem appears to have begun at Rosh Hashana.
Last year, Rosh Hashana fell in early September. Later that month, measles cases exploded in Israel, rising to a peak of 949 in October. The cause? Numerous pilgrims came back from Ukraine with the virus, experts believe.
New York’s outbreak began in October; the first patient was a child in the Bensonhurst section of Brooklyn who had visited Israel. At the same time, a measles outbreak began among Orthodox Jews in London.