This is how long it takes for the measles vaccine to work, SC health officials say

It generally takes 10 to 14 days after the first dose of the MMR vaccine to become immune to measles, South Carolina Department of Public Health officials said.

The Centers for Disease Control recommends two doses, 28 days apart.

The vaccine has been so effective, it is credited with eradicating the disease in the United States. The recent outbreak in South Carolina and other states is putting the United States at risk of losing its elimination status.

The Centers for Disease Control says besides being vaccinated you can know if you are immune by having a laboratory test, which can show if you had measles at some point in your life. Also, if you were born before 1957, it is presumed you had the disease and are immune.

Two doses at age 12 months or older ensures lifetime protection. You do not need a booster dose.

The CDC says one dose is sufficient for most adults born during or after 1957 except for those who are at higher risk of coming into contact with people who have the virus, including college students, healthcare and public health providers.

If you don’t know whether you are immune, it does not hurt to get another vaccine.

This story was originally published February 16, 2026 at 5:30 AM.