A recent health alert from the Centers for Disease Control and Prevention (CDC) warns travelers to protect themselves against measles before heading out to visit other countries this summer.
A recent rise in cases of measles sparked the health advisory urging people to check that they've had two doses of the measles-mumps-rubella (MMR) vaccine at least two weeks before leaving on international trips, the CDC said.
Measles, an acute viral respiratory illness, is highly contagious — and 9 out of 10 unvaccinated people who come in close contact with just one person infected by measles can contract the disease.
"The important part [to know] about measles is that you are infectious before the rash hits and you could be infectious up to 60 feet away," Dr. Sharon Nachman, chief of the Pediatric Infectious Diseases division at Stony Brook Children's Hospital in Stony Brook, New York, told Fox News Digital.
The social distancing measures taken during the COVID-19 pandemic are not enough when it comes to avoiding exposure to measles, she also said.
With COVID, she said, "we talked about [a distance of] two arm lengths between people … Those are larger droplets. They fall down," she said.
With measles, she noted, "the aerosolized droplets are quite small, so they pass very far distances away. So you could be going to the opera, and somebody on the right side [of the theater] in one of those boxes is sick with measles — and you're sitting in the orchestra seats. You're going to get infected."
While the highly contagious disease can have short-term effects on people's health, said Nachman, measles contracted at a young age can have a long version of itself as well, much like the COVID-19 virus has its "long COVID" version.
"Measles has its own new or acute illnesses associated with it. Then it's got this kick afterward."
The long condition is called subacute sclerosing panencephalitis (SSPE), she told Fox News Digital in an interview.
SSPE is a progressive neurological disorder that affects the central nervous system in children and young adults. Patients can develop a severe brain infection from six to 10 years after having measles, she said.
This could lead to mental and physical deterioration, coma and even death, noted Nachman.
"It's a time bomb," she said. "Your brain can sort of fall apart. You get encephalopathy, and it's not fixable — and it's never seen with the vaccine. It's really all seen with the disease."
Nachman pointed out, "Measles has its own new or acute illnesses associated with it. Then it's got this kick afterward."
It is estimated that 1 in 500 to 1 in 1,000 children who had measles will develop SSPE, she said.
The number of reported cases of measles has increased to 16 during the first five months of 2023, compared with three cases in 2022 during the same period, said the CDC, as of June 8, 2023.
Measles can still be infectious in the air and on surfaces for up to two hours even after an infected person leaves an area.
Of the 16 reported cases, 14 of them were linked to international travel and most of those people were not vaccinated against measles, the CDC said.
With twice as many Americans estimated to travel internationally in 2023 compared to last year along with declined global vaccination rates during the COVID pandemic, there is concern about a spike in worldwide measles cases, the CDC report noted.
Measles is typically transmitted by an infected person through direct contact with infectious droplets or by airborne spread when an infected person breathes, coughs or sneezes.
Measles can still be infectious in the air and on surfaces for up to two hours even after an infected person leaves an area, according infectious disease experts.
A person can be contagious four days before developing a rash and four days afterward, the CDC report said.
The incubation period for measles typically ranges from seven to 12 days from exposure, experts told Fox News Digital.
Symptoms of measles include fever, cough, runny nose and conjunctivitis, which can last two to four days prior to developing a rash.
Those receiving two doses of the vaccine are likely to be 97% protected against the measles virus.
Complications from measles include pneumonia, inflammation of the brain (encephalitis) and death, according to the CDC report.
Those receiving two doses of the vaccine are likely to be 97% protected against the measles virus, compared to one shot, which provides 93% protection, according to the federal health agency report.
Experts suggested people check with their physicians to find out if they've had one or two vaccinations.
This can vary depending on the year of birth.
Those born in the U.S. before 1957, when measles was common in the U.S., are considered at low risk for measles, the CDC report said — but still, they should speak with their doctor to see if vaccination is recommended.
Suggested measles vaccination doses also varied prior to the mid-to-late '80s, health experts told Fox News Digital.
"Were you born before 1988? You only got one dose — you need a second dose. So that's sort of an easy, a no-brainer," said Dr. Nachman.
But for those born after 1985-88, we think they should have gotten two doses."
She stressed the importance of speaking with a doctor to go over the personal history of vaccinations and current medical status.
Teens and adults who have not been vaccinated against measles should get two doses spread about 28 days apart at least two weeks prior to international travel, said medical professionals.
In some cases, vaccination against measles may not be appropriate.
Those who are immunocompromised, have an underlying medical condition or are undergoing chemotherapy must discuss with a physician whether it's safe to get a measles vaccine, Nachman said.
"Are you on chemo? In which case, no — we don't want you to get another dose," she said.
"We also want you to think about [your destination] — is this a good place to go on a trip now? 'Maybe I shouldn't be going on that trip to that country. I should go someplace else.' So you know, it's not always an easy yes or no," Nachman said.
Currently, it is recommended that children get their first dose at 12 to 15 months of age, then the second dose at age 4, 5 or 6 years old.
The recent CDC report, however, suggested families of infants in the U.S. who are 6–11 months old and who will be traveling abroad should consider having their young ones receive an extra measles, mumps and rubella vaccine (MMR) shot.
Also, teens and adults who have not been vaccinated should get two doses spread about 28 days apart at least two weeks prior to traveling, the report said.
Certain individuals who are vulnerable to complications from measles include infants who are too young to get vaccinated, pregnant women, those with weakened immune systems (including diabetes, organ transplant, cancer and AIDS) or those taking certain medications including immunosuppressants, health experts told Fox News Digital.
Doctors also said anyone born between 1957 and 1985 who may not have had two doses of the vaccine may be at risk and should check with their physician.
Measles remains a common disease in Europe, the Middle East, Asia and Africa, according to the CDC.
Certain popular travel destinations like Israel, India, Thailand, Vietnam, Japan, Ukraine, and the Philippines have seen measles outbreaks in recent years, the CDC reported.
An estimated 128,000 measles deaths occurred globally in 2021, mostly among the unvaccinated or under-vaccinated children younger than five years old, the World Health Organization said.