What travelers should know about measles and other vaccine-preventable diseases.

What travelers should know about measles and other vaccine-preventable diseases; with vaccination rates down, here’s how to protect yourself and your family. (Weston Wei/The New York Times)

By PERRI KLASS, M.D.

With misinformation and disinformation, vaccination rates for measles are worryingly down, and other serious — though vaccine-preventable — diseases are also showing up, among them, whooping cough, rotavirus, meningitis and serious cases of influenza. Doctors are also concerned about the reemergence of polio.

In the United States, there were more cases of measles last year than in any other year since the virus was declared eliminated in 2000, a status the country is now poised to lose. There have been outbreaks in South Carolina, Texas and Utah, but cases have also been reported in more than 30 states.

Measles is the most infectious virus known, so travel raises fears that it will spread. One of the most notorious U.S. outbreaks was travel related: a 2014 exposure at Disneyland.

Pertussis, or whooping cough, was never eliminated, but cases have been rising; it can be fatal in infants and young children. Additionally, doctors worry that unvaccinated people are vulnerable to other infections, such as meningococcal meningitis, which caused an outbreak this year in Britain. And in a population where children are not protected by the measles, mumps and rubella vaccine (MMR), pregnant women also have to worry about exposure to rubella, which can cause devastating damage to the fetus.

The good news is that these diseases can be prevented by vaccines. Making sure that your eligible family members are fully vaccinated before travel can help keep them safe.

Stay safe in airports, on airplanes and in crowded areas.

Measles not only spreads efficiently, but it also hangs in the air and remains infectious for a couple of hours. It also survives on surfaces, as does hepatitis A, rotavirus and influenza.

So you don’t have to be in the room or on the bus with the sick person. The most infectious period for measles begins before the rash appears. People who are coming down with the disease often have runny noses, and yes, there’s virus in the mucus, as well as in their breath, coughs and sneezes.

Those who are not yet completely vaccinated might consider masks — which also protect against other infections — in airports, airplanes and other crowded circumstances. Unvaccinated and immunocompromised people should consider avoiding crowds, especially indoors.

Good hand washing is also important when traveling and helps protect you against more than measles.

Consider your route and destination.

For domestic travel, many states other than Texas, South Carolina and Utah have reported cases. Last December, the New Jersey Department of Health sent out an alert about a measles exposure from a “non-N.J. measles case” at Newark Liberty International Airport. Internationally, measles continues to be a problem; the Centers for Disease Control and Prevention lists the top 10 countries for outbreaks, which include India and Mexico, but cases have been reported all over Europe (Spain and Britain have each recently lost their measles-elimination status). The CDC recommends that travelers be vaccinated before traveling.

The CDC also recommends “enhanced precautions” before travel to countries with circulating polio virus; the list includes Britain, Germany and Poland.

Be sure you’re immune.

Children should be up-to-date on vaccines recommended by the American Academy of Pediatrics; adults should check to see if they need pertussis boosters or adult polio boosters. The MMR vaccine cannot be given if you are pregnant, immunocompromised or have recently had certain other vaccines. It also cannot be given to infants under 6 months. Anyone else who needs a vaccine should get it at least two weeks before traveling.

Adults can find out whether they’re immune by getting a measles titer check (a blood test), though anyone born in the United States before 1957 is assumed to have had measles, and therefore developed immunity. From 1963-67 some children got a less effective vaccine; people born through 1989 may have gotten the right vaccine, but only a single dose. If you know you were vaccinated, but aren’t sure whether you had two doses, have your titer checked, or get an additional dose. If traveling to countries where the polio virus is circulating, children should be fully vaccinated, and adults who were vaccinated as children should consider a booster.

Consider early measles vaccination for children.

Initial doses of many vaccines are given in the first months of life, offering at least partial protection, but the first MMR dose is normally given at age 1. However, if you’re traveling with a child who is at least 6 months old, they can get the first dose early and then get another when they turn 1. (They will end up getting three doses since they still need two doses at and after age 1 to count as fully vaccinated.)

So, the ideal situation is to have received two doses before travel (two doses are 97% effective at preventing measles). But even those who only get a single dose should have significant protection against severe illness.

What to do if you’ve been exposed.

If you know you’ve been exposed to measles, pertussis, polio or meningitis while traveling, consult a doctor right away. In the case of measles, vaccines or immune globulin may be offered. For pertussis, you may be offered antibiotics. Warn the office before you come in, so they can take precautions. Similarly, if anyone gets sick after a trip, let your doctor know about your travels.

Is measles really a serious disease?

Yes, measles kills more than 100,000 people worldwide every year. There were previously healthy children who died of measles in the United States in 2025; many others have been hospitalized. It is a miserable disease, with high fevers and it can result in permanent neurological damage or lead to a delayed, and fatal, degenerative disease.

“We have been able to prevent measles for 60 years and yet we’re still having this conversation,” said Dr. Adam Ratner, a pediatric infectious disease physician in New York and the author of “Booster Shots: The Urgent Lessons of Measles and the Uncertain Future of Children’s Health.”