State health officials Monday said a case of measles has been confirmed in an unvaccinated Oahu resident upon his return from traveling internationally.

The state Department of Health said it has already identified those with known exposure to the patient and is working to prevent the spread of the disease. It is also asking health care providers to be on alert for possible cases.

DOH declined to disclose the age of the person, including whether he is a minor, saying it is still an active investigation. He is in isolation, however, and recovering.

Measles, a vaccine- preventable disease, is very contagious and is caused by a virus that spreads through the air when an infected person coughs or sneezes, officials said.

At the same time, mumps, measles and rubella vaccination rates have dropped among children globally and nationally since pre-pandemic years, according to DOH.

“The pandemic caused setbacks for childhood immunization programs worldwide,” said state Epidemiologist Dr. Sarah Kemble in a news release. “As a result, we are seeing increases in outbreaks globally, and sometimes outbreaks in the United States as well. We are very fortunate to have a safe and highly effective vaccine against measles. This is a reminder to check your child’s immunization status and make sure they are up-to-date on all recommended shots.”

Symptoms usually start with a high fever, cough, runny nose and red, watery eyes, according to the Centers for Disease Control and Prevention.

Two to three days after symptoms begin, there may be tiny white spots inside the mouth. Three to five days after symptoms begin, a rash breaks out, with tiny red spots that usually begin on the face and spread downward to the rest of the body.

Infected people can spread measles from four days before through four days after a rash appears.

Ron Balajadia, DOH immunization branch chief, said officials are working with the person’s medical provider, airline and other places visited to ensure those potentially exposed have been informed and know the symptoms to watch out for.

In the past five years, including this year, there have been seven cases of measles reported to DOH, Balajadia said. There were four in 2019 and two in 2020 but none in 2021 or 2022.

The last major outbreak was in 2014, with 15 cases detected on Oahu, Maui and Kauai, he said.

Measles is not endemic in Hawaii, he said, and the majority of cases are either brought here by someone visiting or by a person who traveled, got infected abroad and then returned to the state.

Most Hawaii schoolchildren get the MMR vaccines required for entry to public schools.

MMR vaccines are part of routine childhood vaccines, with the first dose usually given at the one-year well-child visit, and the second dose at 4 to 6 years of age.

But officials recently expressed concerns that following global and national trends, the percentage of Hawaii children who are not vaccinated for mumps and measles or the full roster of shots required for school has jumped since the arrival of COVID-19 due a growing number seeking religious and medical exemptions.

Measles can cause serious health complications, especially in children under 5 and in infants under 1 who are too young to be vaccinated against measles.

According to CDC, 1 out of every 20 children with measles get pneumonia; 1 out of 1,000 develop encephalitis, or swelling of the brain; and nearly 1 to 3 out of 1,000 children who become infected with measles will die from respiratory and neurological complications.

“All eligible keiki should be vaccinated against measles,” DOH Director Dr. Kenneth Fink said in a statement. “Prevention is easy. Don’t miss an opportunity to protect your child against this serious disease.”

More information about measles is available at cdc.gov/measles.