Measles has been spreading across America, as the Centers for Disease Control and Prevention has reported more than 220 cases nationwide as of March 7.

The uptick in cases began with an outbreak in Texas, where there have been 223 cases identified since late January (as of March 11).

A new case was confirmed in a Howard County, Maryland, resident last week after the individual traveled internationally through Dulles International Airport in Washington, D.C.

U.S. MEASLES OUTBREAK: SEE THE STATES WHERE CASES HAVE BEEN REPORTED

Officials claimed that this case is not related to the Texas outbreak, warning travelers to be on the lookout for measles symptoms if they traveled through the airport around that same time.

Measles is highly contagious and is most threatening to unvaccinated individuals, Fox News’ senior medical analyst Dr. Marc Siegel previously told Fox News Digital.

“There is a 90% chance you will get it if you are unvaccinated and step into a room where someone with measles was two hours before,” he cautioned.

MARYLAND CONFIRMS FIRST MEASLES CASE IN TRAVELER AT MAJOR DC AIRPORT

When traveling in a confined space, such as an airplane, exposure becomes even more of a concern.

In an on-camera interview with Fox News Digital in New York City, Dr. John Whyte, WebMD chief medical officer and practicing physician, emphasized how measles is “one of the most contagious respiratory viruses.” (See the video at the top of this article.)

“The good news is, if you’re immunized, you’re unlikely to be affected.”

“Measles is much more contagious than COVID,” he said. “It’s a factor of several times more contagious.”

One infected person can impact about 10 to 15 other people, according to Whyte.

There are multiple ways to protect yourself from infection while traveling and flying, the doctor said, including being aware of your surroundings and wearing a mask in areas where cases have been detected.

The doctor also recommended “good handwashing” after touching surfaces, as well as keeping surfaces clean, since virus droplets can stick and spread when contact is made.

People who have been infected with measles often do not become symptomatic until four days after exposure, Whyte shared, so it may be difficult to track the origin of the infection.

FLORIDA ALERTS FIRST MEASLES CASE OF YEAR IN PUBLIC SCHOOL AS EXPERTS STRESS VACCINATION

Whyte mentioned that the measles, mumps and rubella (MMR) vaccine is “very effective,” although some people have chosen not to be vaccinated, which is “where we’re seeing those cases,” he said.

Since the MMR vaccine is most commonly administered to children, some adults might not remember if they received it and may be concerned about the strength of their immunity.

Whyte suggested receiving a measles titer, which is a blood test that measures antibody (immunity) levels against the disease.

This is especially important for people who are traveling to other countries, where exposure risk may be higher, the doctor added. For those lacking immunity, MMR vaccine boosters are available.

CLICK HERE TO SIGN UP FOR OUR HEALTH NEWSLETTER

“I’d say if you’re starting to see measles in your area, and you’re concerned about whether or not you have immunity, go to your doctor and get your titers checked,” he advised.

“Otherwise, practice all those good hygiene methods that we talked about. Wash your hands. Wear a mask. Be aware of your surroundings. Clean surfaces.”

For those who are feeling sick, Whyte encouraged staying home and abstaining from traveling to help keep others healthy.

Measles symptoms typically begin with coughing and sneezing, and then lead to a red rash on the face and body several days later.

For more Health articles, visit www.foxnews.com/health

“A lot of physicians [have] never seen measles,” Whyte noted. “So, you have to sometimes prompt your doctor if you think you might have been exposed.”

Measles can cause serious complications, the doctor warned, including brain swelling and pneumonia, particularly in older individuals.

“The good news is, if you’re immunized, you’re unlikely to be affected, even if you come into contact with someone who does have measles,” Whyte said. 

“That’s the whole beauty of immunization.”