ALLENTOWN, Pa. -

From California to New York, American health officials are seeing a resurgence of measles.

In Pennsylvania, a handful of people have been diagnosed, one right here in the Lehigh Valley.

Health officials say the cases involve people who are too young to be vaccinated or who weren't vaccinated at all as a child.

Some people perhaps mistakenly believing the myth that there is a link between vaccines and Autism.

"There's a variety of reasons why people decline vaccines but there is definite public health evidence of the fact that we limit the spread, we limit the transmission by how strong our immunization rates are," said Vicky Kistler, Director of Health for the Allentown Health Bureau.

Kistler says the local case involves an infant who went for a wellness check at Lehigh Valley Health Network's Children's Clinic.

The bureau and LVHN have been working to notify and protect people possibly exposed to the disease.

Kistler says it's unclear where the child was exposed, but with an active outbreak in New York, Pennsylvania is on high alert.

State health officials are closely monitoring the national outbreak database.

"Whenever there is a multi state anything or even a border state anything, usually that information is disseminated back and forth," said Kistler.

The Centers for Disease Control says that in 2000, measles was declared eliminated in the United States.

The CDC says the disease is brought into the country by people who travel and that being unvaccinated puts your health at risk, especially if you're pregnant.

If you have not been vaccinated, health officials say you should talk to your doctor.