David Sugerman, MD, MPH
All measles cases in the United States originate from international travel. Your patients are at risk for measles infection if they have not been fully vaccinated. The best way to protect them from this serious disease — and prevent potential measles outbreaks in the US — is vaccination before travel.
In addition, if you see patients coming to the US from measles-endemic countries such as Afghanistan, Somalia, or the Democratic Republic of Congo, assess their vaccination history and offer recommended vaccines, including MMR for measles, mumps, and rubella, and IPV for polio.
In 2020, because of COVID-19 pandemic restrictions, the number of overall well-baby visits fell, causing a delay in routine childhood immunizations, as confirmed by a notable decrease in provider vaccine ordering and administration, which has likely resulted in lower childhood immunization coverage in 2020 and may continue to affect routine vaccination rates in 2021.
Measles remains a common disease in many parts of the world, including Europe, the Middle East, Asia, and Africa. Each year, an estimated 140,000 people die from measles. Many countries, including the US, have experienced measles outbreaks in recent years, including popular travel destinations like Israel, Thailand, Vietnam, Japan, Ukraine, the Philippines, and more.
Let’s tackle common questions clinicians ask about measles vaccination and travel.
Do measles outbreaks still happen in the United States?
Measles continues to be brought into the United States by travelers, mostly unvaccinated US residents who were infected while in other countries. In 2019, the CDC recorded the largest number of measles cases in the US, with over 1200 reported cases. This included two large, closely connected outbreaks in New York City and New York State that accounted for 75% of all cases. That same year, four European countries (Albania, Czech Republic, Greece, and the United Kingdom) lost their measles elimination status.
Low community vaccination coverage due to low vaccine confidence, high population density, the closed social nature of the affected communities, and repeated introduction of measles from unvaccinated international travelers contributed to the “perfect storm” in the 2019 outbreaks in the US.
Isn’t measles eliminated in this country?
Yes, for now, but measles can be just a plane ride away. The New York City and New York State outbreaks in 2019 lasted almost a year and threatened the US measles elimination status, which is based on the absence of endemic measles transmission in a defined geographical area (eg, region or country) for ≥ 12 months in the presence of a well-performing surveillance system.
Since 2000, the annual number of people reported to have measles ranged from a low of 37 people in 2004 to a high of 1282 cases in 2019. Between 2001 and 2019, most of the US measles importations came from India, the Philippines, China, the United Kingdom, Japan, and the Ukraine.
Doesn’t the US have a high MMR vaccination coverage?
While historically the mumps-measles-rubella (MMR) child vaccination coverage is relatively high (an estimated 91.3% of children 19-35 months old who were surveyed in 2019 received > 1 MMR dose, according to the 2019 National Immunization Survey-Child), pockets of unvaccinated people still exist in some communities, creating considerable measles susceptibility at local levels.
Some recent drops in coverage may be attributed to a delay in routine childhood immunizations because of pandemic restrictions, but ongoing misinformation and disinformation about vaccines erode confidence in vaccination and can make our efforts to catch up on childhood vaccination more difficult in some communities. Because vaccines are so effective, many vaccine-preventable diseases, including measles, no longer seem like a threat, and some parents may not realize just how dangerous these diseases can be. Easy access to conflicting and inaccurate information about vaccines may cause parents to avoid vaccination or use an alternative vaccine schedule not recommended by ACIP/CDC; these delays can mean that children are not fully protected.
Healthcare providers like you remain the most trusted source of information about vaccines, and a recommendation from a clinician is the strongest predictor of vaccine acceptance. To help you navigate conversations about vaccines with parents, you can use CDC’s resources for clinicians.
What about babies who are going to be traveling internationally?
As international and domestic travel returns to pre-pandemic levels, many families with children born during the pandemic who were unable to visit relatives may now be traveling internationally for the first time. Those traveling to their native country or to a resort or vacation destination may not perceive it as risky or unsafe travel. The routine recommendation for the MMR vaccine starts at age 12 months. However, infants can get the vaccine as early as 6 months old if they are traveling outside of the United States. Many people may not be aware of the alternative vaccination schedules recommended when traveling abroad, so it’s often up to you, the clinicians, as well as your staff, to ask parents with small children if they may be traveling.
Should I recommend the measles vaccine for certain destinations?
It is critical for all international travelers to be protected against measles, regardless of their destination. You can take this opportunity to remind the whole family of the importance of being up-to-date on all vaccinations before travel.
Before traveling internationally, people should plan to be fully vaccinated at least 2 weeks before departure. If the trip is less than 2 weeks away and they are not protected against measles, they should still get a dose of MMR vaccine. Two doses of MMR vaccine provide 97% protection against measles; one dose provides 93% protection. Infants can get an early dose of MMR at 6-11 months, followed by another dose at 12-15 months, and a final dose at 4-6 years.
Children over 12 months old who have not received any MMR vaccine should get their first dose immediately and second dose 28 days after the first. Teens and adults with no evidence of immunity should get the first dose immediately and the second dose 28 days after the first. ACIP always recommends using the minimal 1-month interval if travel is impending.
(Note: Acceptable presumptive evidence of immunity against measles includes at least one of the following: written documentation of adequate vaccination, laboratory evidence of immunity, laboratory confirmation of measles, or birth in the United States before 1957.) CDC does not recommend measles vaccine for infants younger than 6 months of age.
To find up-to-date information about the measles vaccination travel schedule, you can visit the CDC webpage about measles vaccination for travelers. You can also help your patients assess whether they need measles vaccine with this online tool . For information about outbreaks and other travel notices, visit cdc.gov/travel/notices.
What if my patient was exposed to measles?
People exposed to measles who cannot readily show that they have evidence of immunity against measles should be offered post-exposure prophylaxis (PEP). To potentially provide protection or modify the clinical course of disease among susceptible persons, administer MMR vaccine within 72 hours of initial measles exposure, or immunoglobulin (IG) within 6 days of exposure. Do not administer MMR vaccine and IG simultaneously, as this practice invalidates the vaccine.