ROCKLAND COUNTY, New York (WABC) -- The number of confirmed measles cases linked to international travelers returning to New York from Israel is up to 17, with 11 in Rockland County and six in Brooklyn.
Rockland health commissioner Dr. Patricia Schnabel Ruppert issued a letter to schools that were attended by students with confirmed cases, informing them that any unvaccinated students must remain home until at least November 3.
Officials said three schools are affected, but they declined to identify which three.
Students are considered protected against measles if they have received the Measles-Mumps-Rubella (MMR) vaccine. Unless otherwise indicated, two doses of MMR vaccine are required for a student to remain in school.
Any student who has not received their first dose of MMR vaccine cannot be allowed to attend school for 21 days after the last date of exposure, which at the time is October 12. This means that these students must remain at home until November 3. 2018, even if they receive their first dose of MMR vaccine during this period of time.
Students in kindergarten through 12th grade who have received one dose of MMR vaccine must also remain home until November 3, unless they receive their second dose. Those students may return at any time after receiving this second dose.
Students in prekindergarten with one dose of MMR are up to date for their age and do not have to remain home from school. However, it is recommended that they receive a second dose of MMR vaccine.
Rockland now has 11 total confirmed cases of measles from three different groups who traveled to Israel. Of those cases, two are secondary, meaning they originated from exposure occurring in Rockland. Meanwhile, six cases of measles were confirmed this month in the Orthodox Jewish community in Williamsburg, Brooklyn.
New York City officials say the initial case of measles was acquired by a child on a visit to Israel. The individuals with measles range in age from 11 months to 4 years, and five of the children were unvaccinated prior to exposure.
One child was hospitalized with pneumonia, while another child had an ear infection.
More cases increase the potential for further exposure, and health officials recommend that residents make sure they and their families are up-to-date on their measles vaccinations.
Israel is currently experiencing a high number of measles cases. In the most recent data compiled by the World Health Organization (WHO), 339 cases have been reported in Israel from March through August of 2018.
For those who believe they may have been exposed and have further questions, a toll-free hotline has been established: 1-888-364-4837. The hotline is available Monday through Friday from 9 a.m. to 5 p.m.
The first case of international travel was in late September, and two more cases due to separate international travelers in early October are leading to more potential cases of measles among non-immune residents.
RELATED: What to know about measles symptoms, vaccine and treatment
Symptoms include a fever, rash, cough, conjunctivitis or runny nose, and they could appear 10 to 12 days after exposure.
The virus can remain in the air or on surfaces for up to two hours.
To prevent the spread of illness, health officials are advising individuals who may have been exposed and who have symptoms consistent with measles to contact their health care provider, a local clinic, or a local emergency department before going for care.
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New York measles cases up to 17, unvaccinated students must stay home