Nassau County reports its first measles case since 2024

A case of measles has been reported in a child who resides in Nassau, the first confirmed infection in the county in just over two years, health officials said Monday.

The child, identified only as younger than age 5, was not vaccinated against the "highly contagious" airborne respiratory virus, the county Department of Health said in a news release.

State and Nassau health officials are "investigating the case and taking necessary proactive steps to prevent further spread of the illness," the release said.

The last confirmed measles case in Nassau was in March 2024, according to the county health department. Suffolk County reported its most recent measles case in March 2025, Newsday previously reported.

Measles spreads through the air from an infected person’s coughs and sneezes. It can also be contracted through a healthy person’s contact with a surface contaminated with an infected person’s nose or throat secretions, followed by touching their own face.

The virus causes coughing, fever, runny nose and watery eyes before it induces a rash. These symptoms can begin a week after exposure, but more often appear after 10 to 12 days. Those infected can spread it from four days before to four days after they develop a rash.

"Measles can cause serious illness, with complications that may include pneumonia, encephalitis, and often results in hospitalization and sometimes death," Nassau County Health Commissioner Dr. Irina Gelman said in a statement. "We strongly encourage residents to protect themselves and their families by making sure they are up to date on important, lifesaving immunizations."

Vaccination through two doses of the MMR vaccine is the "single best way to prevent measles," the health department said. While the vaccine is "very safe," side effects are possible, but are "usually mild and go away on their own," the release said.

Ten cases of measles have been reported statewide so far in 2026, according to the New York State Department of Health website. State health officials could not be immediately reached to confirm if that figure included the Nassau case.

The Centers for Disease Control and Prevention recommends children receive their first MMR dose between 12 and 15 months, and their second between ages 4 and 6. Childhood measles vaccination rates nationwide dropped below the 95% rate necessary to prevent outbreaks, according to The Associated Press.

In 2025, 82% of children between 24 and 35 months received their first MMR shot by age 2, Newsday previously reported. In Nassau. That figure was 82.6% in Suffolk.