My measles shot was years ago. Am I still protected?

As the measles outbreaks spread, many people are growing concerned. New York City declared a public health emergency and mandated vaccinations in four ZIP codes where vaccination rates have been low. A Israeli flight attendant is in a coma from being infected with the highly contagious disease.

As a professor who teaches courses in immunology, microbiology and vaccine public policy, I research the fundamental processes of how our bodies respond to infections and vaccines to generate protective immunity. In my teaching, I work with students to develop an understanding of the complexity of these issues and encourage them to engage in the public discourse on these topics from balanced and informed perspective. Given all the attention around measles, here’s what people who believe they have been vaccinated should know.

I received my vaccines more than 30 years ago. Am I still protected?

Yes, according to the Centers for Disease Control and Prevention, the measles component of the MMR vaccine provides lifelong protection.The mumps and rubella portions are not as long-lived. One dose of the MMR vaccine protects against measles at 93 percent efficacy (that is, 93 percent of individuals will receive the protective benefit of the vaccine), two doses of the vaccine provides 96-97 percent efficacy. The Advisory Committee on Immunization Practices at the CDC began recommending two doses of the MMR vaccine in 1989 in response to a measles outbreak in children who had been vaccinated by only a single dose.

I’m not sure that I received two doses of the MMR. Do I need another shot?

Concerned individuals should contact their physician for recommendations on how best to proceed. The CDC recommends the following are considered “evidence of immunity” that would make vaccination considered unnecessary: written documentation of vaccination; one or more doses of a vaccine containing measles administered on or after the first birthday for preschool-age children and adults not at high risk; two doses of measles-containing vaccine for school-age children and adults at high risk, including college students, health care personnel, and international travelers; laboratory evidence of immunity; laboratory confirmation of measles; or birth before 1957. Surveys suggest that 95-98% of individuals born before 1957 were exposed to measles as children, giving them lifelong natural protection.

I don’t have my vaccination records, and I’m not sure I even received one dose. What should I do?

Talk to your provider; you may need a shot. The CDC recommends that all individuals born after 1957 receive a vaccine for the measles. Measles is not strictly a childhood disease and adults and teenagers should be up-to-date on their vaccination. If you do not know your vaccine status, best practices would suggest you speak with your physician about receiving the vaccine. The CDC has the following recommendation for adult vaccinations against the measles: “Adults who do not have evidence of immunity should get at least one dose of MMR vaccine.” Of particular emphasis are international travelers, health care professionals, women of childbearing age, close contacts of immunocompromised individuals, and people with human immunodeficiency virus (HIV).

Should some people not be vaccinated?

Yes. The CDC recommends that you tell your vaccine provider if the person getting the vaccine:

Other than being vaccinated, is there anything else I can do to stay safe?

Vaccination is the single best preventative strategy in avoiding the measles. As is the case for all contagious infections, proper hygiene practices, self-isolation while sick and avoiding contact with sick individuals are also useful practices in limiting the contraction and spread of disease.

Eyal Amiel is assistant professor of biomedicine and health sciences at the University of Vermont. This article first appeared on The Conversation.