Do you need a measles booster shot? What to know as a U.S. outbreak spreads

Dr. Céline Gounder, CBS News medical contributor and editor-at-large for public health at KFF Health News, said on "CBS Mornings" Monday the need for another dose depends on your age and vaccination history.

"There is a very specific group that does have to worry about their immunity from vaccination. People born after 1957 but vaccinated before 1968 — that group is unlikely to have robust immunity from infection," she said, because "at that point in time, they were using less effective vaccines."