Seven Months of Measles: The 2018–2019 Outbreaks in New York and New Jersey

New York State's schools reported a measles vaccination rate of 98% in 2017–2018. In the schools of the area where measles broke out that autumn, documented coverage was 77%. That gap is the story of the outbreak.

How it arrived

On October 1, 2018, the Rockland County Department of Health told the New York State Department of Health about an unvaccinated teenager back from travel with measles. Over the next 17 days the county learned of six more unvaccinated travelers with the disease. On October 24, Ocean County told the New Jersey Department of Health of a case in an international traveler whose rash had begun on October 17. The travelers had recently been in Israel, where an outbreak of about 3,150 cases was under way.

The cases were mostly in members of orthodox Jewish communities.

Measles cases by date of rash onset: New York (242, excluding New York City) and New Jersey (33). CDC.

Two outbreaks, side by side

The youngest New York case was a baby who tested positive at birth, born to a mother who had measles during pregnancy. New Jersey's community had a second outbreak in March 2019, with no identified connection to the first.

What the health departments did

Schools. Rockland and neighboring Orange County kept unvaccinated students out of school for 21 days after an exposure. In parts of Rockland with cases, that was widened to every nonimmune student at schools whose measles immunity rate — two valid doses of MMR vaccine, or blood-test proof — was under 95%. Ocean County also used the 21-day exclusion, and some private schools there kept unvaccinated students out for the whole outbreak.

Vaccine. Rockland County gave 19,661 MMR doses between October 1 and April 30, and held about 20 community vaccination events open to all ages; Orange County held two. New Jersey helped deliver more than 12,500 outbreak-response MMR doses to Ocean County providers.

Information. New York's state and county health departments and private providers held nine informational events and sent measles-prevention materials to 45,000 homes. A culturally appropriate, detailed vaccine education book went to 15,000 homes and providers in Rockland County and 10,000 in Orange County. Rabbinical leaders supported vaccination, and community groups advocated for it.

Why it lasted

The New York outbreak became the largest in the state outside New York City since 1992 and, at seven months, the longest documented outbreak in the United States since endemic measles was eliminated in 2000. Low community vaccination let measles spread widely once unvaccinated travelers brought it in.

The authors' conclusions: step up education about the risks of undervaccination where rates are low; clinicians and health departments should know about the many outbreaks under way worldwide, and travelers should have evidence of measles immunity; and every U.S. community should keep age-appropriate coverage with two MMR doses at 95% or higher to maintain herd immunity.

Sources

Based on McDonald R, Ruppert PS, Souto M, et al., "Notes from the Field: Measles Outbreaks from Imported Cases in Orthodox Jewish Communities — New York and New Jersey, 2018–2019," MMWR Morbidity and Mortality Weekly Report volume 68, number 19, Centers for Disease Control and Prevention; a work of the United States government in the public domain. The imported copy was cut short; the missing text is from the report's full text in PubMed Central (PMC6522080).