Connecticut is dealing with its first measles case since 2021.

State Department of Health officials said a Fairfield County child, who is under the age of 10 and not vaccinated, contracted the virus while traveling internationally, adding the child started showing symptoms several days after returning.

What to know about measles

The Centers for Disease Control and Prevention says measles is very contagious and can spread quickly through the air when an infected person coughs or sneezes. It says 9 out of 10 unvaccinated people who come into contact with infected person will get the virus. Symptoms include cough, runny nose, fever, watery eyes, and rash.

At the time the rash appears, a person's fever may spike to more than 104 degrees Fahrenheit, officials say.

Measles can cause serious health complications, especially in children younger than 5. Hospitalization occurs in 1 in 5 unvaccinated people in the U.S. who contract the virus.

Two doses of the MMR vaccine provide the best protection against measles, the CDC says. Connecticut health officials say more than 98% of students have received the MMR vaccine by the time they reach kindergarten, the highest rate of any state in the nation.

"The single best way to protect your children and yourself from measles is to be vaccinated," said DPH Commissioner Dr. Manisha Juthani. "One dose of measles vaccine is about 93% effective, while two doses are about 97% effective. We must ensure we continue to protect those who matter most -- children and other vulnerable people -- from vaccine preventable illnesses through on-time vaccination."

New York City data shows 93% of children ages 24-35 months have received at least one dose of the MMR vaccine by their second birthday, adding 97% of the city's kindergartners are vaccinated.

Measles cases nationally

The CDC says there have been more than 1,900 confirmed cases nationally this year, the most since health officials declared the virus eliminated in the U.S. in 2000. There have also been three deaths, as of Dec. 9.

Texas has had by far the most cases with 803, followed by South Carolina with 123.

There have been 21 confirmed cases in New York this year, including 15 in New York City. New Jersey has had 11 confirmed cases.