Is It Possible To Catch Measles If You’ve Been Vaccinated?

According to the Centers for Disease Control and Prevention (CDC), the number of measles cases in the United States is on the rise, with more than 550 cases reported this year. The CDC says this is the second highest number of measles cases reported in any year since 2000. And many of the cases have occurred as part of an ongoing measles outbreak in several U.S. cities, generally affecting people who were unvaccinated.

But the questions remain whether or not you can catch the disease in spite of vaccination? Although it is possible to catch measles after being vaccinated, it is not often the case.

According to the CDC, the two doses of the measles, mumps and rubella vaccine (MMR) are given as part of the standard U.S. childhood vaccination schedule. This helps a large percentage of children being covered against MMR- with approximately 97% effective at preventing measles. This means that about 3% of children who have received the two doses of the measles vaccine could still get measles if they are exposed to the virus. Moreover, some people may be at a marginally greater risk of contracting measles because they received only one dose of the MMR vaccine.

The CDC says that though the measles vaccine was developed and available since 1963, it was not until 1989 that health officials recommended children receiving two doses of the vaccine.

Dr. Amesh Adalja is a senior scholar at The Johns Hopkins Center for Health Security in Baltimore. He says this could mean that there are many people in their adulthood, who only received one dose back in the day. Dr. Adalja says although one dose of MMR is still more than 90% effective at preventing measles, it’s not quite as good as two doses. He says it would be a wise choice for adults who received only one dose of MMR as a child to consider getting a second dose.

Furthermore, The CDC suggests that people who received the measles vaccine in the 1960s may need to be revaccinated. This is due to the fact that between 1963 and 1967, some people received a form of the measles vaccine known as the “inactivated” vaccine, which was not effective People who received this form of the vaccine, or were vaccinated before 1968 and don’t know what vaccine type they got, should be revaccinated with the current form of the vaccine with “live virus”.

Another question people may have is whether the vaccine’s protection wanes over time. Dr. Adalja says that usually people who’ve received both doses of MMR vaccination are considered protected for their lifetime, but there may be some fading that happens with age, and they may need a booster shot to help with the vanishing effects of the vaccination.

One way to check your level of protection against measles is to get a blood test that measures antibody levels against the measles virus. However, this is not a routine test performed on general patients and is more often used for health care workers who are at a higher risk of being exposed to measles.