Health Secretary Jeremy Hunt said that the "myth" surround the MMR jab must be "slayed", after health officials reported that the number of measles cases had risen to 886.
Shamed doctor Andrew Wakefield was struck off the medical register for his discredited research which claimed to find a link between autism and the MMR vaccine.
Speaking to the Health Select Committee, Mr Hunt said: "We certainly must not think of this as something that is just happening in Wales.
"[There] is still that critical 11 to 15-year-old age group that may not have been vaccinated because they were toddlers at precisely the time when the MMR scare was so appallingly whipped up.
"I want to reassure you, we are taking this extremely seriously inside the Department of Health."