This post has been updated.

Surgeon General Vivek H. Murthy urged parents Wednesday to vaccinate their children against the measles, saying that while he understood concerns some may have, the immunizations have been proven safe and effective.

"The most important message I have is to please, please, please get your child vaccinated," Murthy said in a brief interview.

"I recognize that some of the concerns parents have about vaccinations come from a place of wanting to do the best to protect their children," he added. But "I believe that on this topic, the science is very clear."

Murthy's remarks add the voice of the government's top public health official to the debate over vaccinations that has erupted in the wake of a measles outbreak that began in December in Disneyland theme parks in Southern California. As of Monday, there were 102 confirmed cases of the highly contagious disease in 14 states. That pace would surpass last year's total of 644 cases. Measles was declared eliminated in the United States in 2000, but has bounced back.

Officials from the Centers for Disease Control and Prevention have attributed the spread to communities, some in California, where larger than average groups of people decline to have their children vaccinated for personal reasons or because they mistrust the vaccine. A discredited 1998 study suggested that the measles vaccine could cause autism, but belief in that idea persists.

President Obama has urged parents to immunize children. But Republican Sen. Rand Paul (R-Ky.), a likely presidential candidate, said Monday he believes most vaccines should be voluntary and, on the same day, New Jersey Gov. Chris Christie called for "some measure of choice" on whether injections that protect children against measles and other disease should be required.

Update: On Wednesday, likely GOP presidential candidate Jeb Bush said that "parents ought to make sure their children are vaccinated."

Murthy noted that physicians have a small amount of flexibility in the vaccine schedule for parents who find it difficult to see children receive multiple injections at one visit. But the government's recommended immunization schedule, and the vaccines themselves have been repeatedly studied and determined safe and optimally effective, he said.

Measles is highly contagious, so pockets of unvaccinated people, children too young to be inoculated and people who cannot be immunized because of other health problems are vulnerable to the virus, which is best known by a rash of red dots on the skin. Most people recover, but complications can include pneumonia, deafness, brain swelling and, in rare cases, death.

Like Ebola, measles entered the United States from other parts of the world where much larger outbreaks have been raging. But in this case, Murthy said, "we have a vaccine that is proven safe and effective. We can protect ourselves [and] protect those around us."

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