If you were born in the United States in or after 1957, you were probably vaccinated against measles. But there’s no harm in getting a booster dose of the vaccine if you’re not sure of your immunity status.
Whether you need to be vaccinated, and how urgently, depends on several factors-including your immunization history, your likelihood of coming into contact with an infected person, and whether you could transmit measles to someone at high risk of complications from it (such as a person with a compromised immune system) if you were to become infected.
As a general rule, measles vaccination is most important for young children, among whom the virus can spread especially rapidly (via crowded kindergarten or preschool classrooms), and who may have infant siblings at home who are too young to be vaccinated. They should receive two doses of the MMR (measles-mumps-rubella) vaccine, with the first given around age 1 and the second before starting kindergarten.
But amid the current measles outbreak, many adults are understandably wondering whether they should get a booster vaccine, especially if they were born in or after 1957. (Adults born before 1957 are presumed to be immune to the measles.)
The Centers for Disease Control and Prevention (CDC) says that you should be vaccinated (or revaccinated) if you can’t provide evidence of immunity to measles, defined as at least one of the following:
- Written documentation that you received, on or after your first birthday, at least one dose of live measles vaccine (which became available in 1968), if you’re at normal risk. If you’re in a high-risk group, you need two documented doses of the live vaccine, given at least 28 days apart. High-risk individuals include healthcare workers, college students, people traveling internationally, and people living in a community with a current measles outbreak.
- A laboratory-confirmed case of measles
- Laboratory evidence of immunity (via a blood test for measles antibodies)
- Birth year before 1957
If you don’t have evidence of immunity, you should either have a blood test for measles antibodies or simply get vaccinated. Of course, the second option is more efficient and poses less of a burden on the healthcare system, since you’ll need only one visit to a doctor rather than potentially two. There’s no downside to getting an extra dose of measles vaccine, and there’s currently no shortage of the vaccine in the United States. On the other hand, if you prefer not to get immunized unless you know for sure that you need it, you can first get the blood test and get a booster only if the results-which typically come back within a few days-show that you’re not immune.
Individuals with a life-threatening allergy to a vaccine ingredient shouldn’t receive the measles vaccine. People with compromised immunity are high risk for complications if they get the vaccine. Pregnant women should not get the vaccine because of theoretical risks to the fetus.
Instead, those who aren’t vaccinated must depend on herd immunity for protection. Herd immunity occurs when enough people get vaccinated, thereby providing a degree of protection for those who can’t be vaccinated since they’re less likely to come in contact with an infected person.
You can read the CDC’s full vaccine recommendations and get up-to-date information on the measles outbreak at cdc.gov/measles.